Cement is a binding agent that undergoes hydration when mixed with water. There are various types of cement including ordinary Portland cement (OPC), rapid hardening cement, and sulphate resisting cement. Cement provides early strength through C3S and later strength through C2S. Heat is generated during cement hydration through an exothermic reaction. Proper storing, grading of aggregates, minimizing segregation, and adding admixtures can improve the properties of concrete.
This document discusses several special concreting techniques:
- Pumped concrete is concrete that can be pushed through a pipeline and must have a design that prevents blockages.
- Shortcrete or gunite is a mortar or fine concrete pneumatically projected at high velocity, used for thin sections with less formwork.
- Underwater concrete requires special mixes placed via bagging, buckets, tremie pipes, or grouted aggregates to prevent water intrusion.
- Other techniques include pre-packed concrete placed underwater and special considerations for hot/cold weather concreting. Proper mix design and placement methods are essential for successful implementation of special concreting applications.
The document discusses the gel/space ratio in concrete and its relationship to concrete strength. It states that the gel/space ratio governs the porosity of concrete, with a higher ratio resulting in lower porosity and higher strength. The gel/space ratio is affected by the water/cement ratio, as a higher water/cement ratio decreases the gel/space ratio by increasing porosity. Power's experiment showed the strength of concrete has a specific relationship to the gel/space ratio that can be calculated.
This document provides information on concrete mix design, including objectives, basic considerations, and the IS (Indian Standards) method for mix design. The objectives of mix design are to achieve the desired workability, strength, durability, and cost. Basic considerations include cost, specifications, workability, strength, durability, and aggregate grading. The IS method is then described in steps, including selecting target strength, water-cement ratio, air content, water and sand contents, cement content, and aggregate contents. An example application of the IS method is also provided.
Rigid pavements are concrete slabs that distribute vehicle loads through beam action. They have high flexural strength and small deflections compared to flexible pavements. The presentation discusses the types of rigid pavements including jointed plain concrete, jointed reinforced concrete, and continuously reinforced concrete pavements. It also covers the design factors for rigid pavements such as traffic loading, subgrade strength, environmental conditions, and material properties. Rigid pavements are designed to last 30 years with minimal maintenance required over the design life.
Cracks in concrete and its remedial measures kamariya keyur
Cracks in concrete can be caused by various factors like plastic shrinkage, drying shrinkage, thermal variations, chemical reactions, errors in design and construction practices, structural overloads, foundation movement, and vegetation. The document classifies cracks as structural or non-structural and describes different types of cracks that can occur before or after concrete hardening. It provides details on the causes and prevention measures for different types of cracks like plastic shrinkage, drying shrinkage, crazing, thermal cracks, cracks due to chemical reactions, and those arising from poor construction practices. The summary focuses on the key information around classification, types, causes and remedies of cracks in concrete structures.
Curing concrete is important to allow the cement hydration process to continue and develop strength over time. Proper curing ensures concrete reaches its designed strength and durability by controlling moisture loss. Common curing methods include water curing through ponding, sprinkling or wet coverings; membrane curing using plastic sheeting or curing compounds; and steam curing to accelerate strength gain. Curing should continue for at least 7 days for normal concrete and 14 days if blended cements are used. Inadequate curing can lead to reduced strength, increased permeability and poor durability.
This document discusses concrete construction in extreme hot and cold weather conditions in India. It addresses the challenges of hot weather concreting such as increased water demand, accelerated slump loss, and increased risk of plastic shrinkage cracking. Recommendations for hot weather concreting include cooling the concrete, reducing placement time, and prompt curing. Cold weather concreting risks include reduced strength if water freezes within concrete. Recommendations include protecting concrete from freezing, using accelerants, and maintaining minimum curing temperatures. Proper planning, materials, and protection methods can help produce quality concrete despite temperature extremes.
This document discusses several special concreting techniques:
- Pumped concrete is concrete that can be pushed through a pipeline and must have a design that prevents blockages.
- Shortcrete or gunite is a mortar or fine concrete pneumatically projected at high velocity, used for thin sections with less formwork.
- Underwater concrete requires special mixes placed via bagging, buckets, tremie pipes, or grouted aggregates to prevent water intrusion.
- Other techniques include pre-packed concrete placed underwater and special considerations for hot/cold weather concreting. Proper mix design and placement methods are essential for successful implementation of special concreting applications.
The document discusses the gel/space ratio in concrete and its relationship to concrete strength. It states that the gel/space ratio governs the porosity of concrete, with a higher ratio resulting in lower porosity and higher strength. The gel/space ratio is affected by the water/cement ratio, as a higher water/cement ratio decreases the gel/space ratio by increasing porosity. Power's experiment showed the strength of concrete has a specific relationship to the gel/space ratio that can be calculated.
This document provides information on concrete mix design, including objectives, basic considerations, and the IS (Indian Standards) method for mix design. The objectives of mix design are to achieve the desired workability, strength, durability, and cost. Basic considerations include cost, specifications, workability, strength, durability, and aggregate grading. The IS method is then described in steps, including selecting target strength, water-cement ratio, air content, water and sand contents, cement content, and aggregate contents. An example application of the IS method is also provided.
Rigid pavements are concrete slabs that distribute vehicle loads through beam action. They have high flexural strength and small deflections compared to flexible pavements. The presentation discusses the types of rigid pavements including jointed plain concrete, jointed reinforced concrete, and continuously reinforced concrete pavements. It also covers the design factors for rigid pavements such as traffic loading, subgrade strength, environmental conditions, and material properties. Rigid pavements are designed to last 30 years with minimal maintenance required over the design life.
Cracks in concrete and its remedial measures kamariya keyur
Cracks in concrete can be caused by various factors like plastic shrinkage, drying shrinkage, thermal variations, chemical reactions, errors in design and construction practices, structural overloads, foundation movement, and vegetation. The document classifies cracks as structural or non-structural and describes different types of cracks that can occur before or after concrete hardening. It provides details on the causes and prevention measures for different types of cracks like plastic shrinkage, drying shrinkage, crazing, thermal cracks, cracks due to chemical reactions, and those arising from poor construction practices. The summary focuses on the key information around classification, types, causes and remedies of cracks in concrete structures.
Curing concrete is important to allow the cement hydration process to continue and develop strength over time. Proper curing ensures concrete reaches its designed strength and durability by controlling moisture loss. Common curing methods include water curing through ponding, sprinkling or wet coverings; membrane curing using plastic sheeting or curing compounds; and steam curing to accelerate strength gain. Curing should continue for at least 7 days for normal concrete and 14 days if blended cements are used. Inadequate curing can lead to reduced strength, increased permeability and poor durability.
This document discusses concrete construction in extreme hot and cold weather conditions in India. It addresses the challenges of hot weather concreting such as increased water demand, accelerated slump loss, and increased risk of plastic shrinkage cracking. Recommendations for hot weather concreting include cooling the concrete, reducing placement time, and prompt curing. Cold weather concreting risks include reduced strength if water freezes within concrete. Recommendations include protecting concrete from freezing, using accelerants, and maintaining minimum curing temperatures. Proper planning, materials, and protection methods can help produce quality concrete despite temperature extremes.
Admixtures are materials added to concrete mixes to modify properties. There are two main types - chemical and mineral. Chemical admixtures include plasticizers, superplasticizers, retarders, accelerators, and air-entraining agents. Mineral admixtures include fly ash, slag, and silica fume. Admixtures are used to increase workability, strength, and durability while decreasing water demand and permeability. Common admixtures like plasticizers and superplasticizers work by dispersing cement particles and lubricating the mix to increase flowability.
The document discusses various aspects of tunnel engineering. It begins by introducing tunnels and their uses for transportation. It then discusses the Thames Tunnel in London as an example. The document outlines several advantages of tunneling over other methods. It also discusses considerations for selecting tunnel routes and economies of tunneling. The remainder of the document describes various tunneling methods through both rock and soft ground, as well as tunnel drainage, lighting, ventilation, lining, and maintenance.
Properties of fresh and Hardened ConcreteVijay RAWAT
The document discusses various properties of fresh and hardened concrete. It describes workability, consistency, segregation, bleeding, mixing, placing, consolidating, and curing of fresh concrete. It also discusses compressive strength, tensile strength, modulus of elasticity, permeability, and durability of hardened concrete. The key properties of fresh concrete include workability, consistency, segregation, bleeding, setting time, and uniformity. Compressive strength is identified as the most important property of hardened concrete.
This document discusses different methods for soil stabilization, including mechanical, physical, chemical, and bituminous stabilization. Mechanical stabilization involves compacting soil to increase density and strength. Physical stabilization involves blending soils or adding admixtures to improve properties. Chemical stabilization uses lime, cement, or other chemicals like calcium chloride to react with soils and modify their characteristics. Bituminous stabilization involves adding bitumen or asphalt to seal soil pores and increase cohesion between particles. The document provides details on appropriate soil types, required quantities, and construction methods for each stabilization technique.
This document provides details for estimating the cost of constructing a two room office building, including specifications, dimensions, and calculations. It begins by outlining the footing, floor, and roof details. It then provides a three step process for cost estimation: [1] excavation, [2] PCC (plain cement concrete) for foundations, and [3] calculating quantities of cement, sand, and aggregate required for the PCC based on the volume. Calculations are shown using the center line method to determine excavation and concrete quantities based on wall lengths and dimensions.
MEANING OF MIX DESIGN
GRADE OF CONCRETE.
FACTORS INFLUCING THE CHOICE OF MIX DESIGN.
MATHODS OF CONCRETE MIX DESIGN
MIX DESIGN BY INDIAN STANDARD METHOD.
Design of rigid pavements. IRC method of design of rigid pavement. Transportation Engineering. Civil Engineering. Wheel loads on rigid pavement. Action of various stresses on rigid pavement. Highway engineering. How rigid pavements different from flexible pavements
Workability refers to the ease with which fresh concrete can be mixed, placed, compacted and finished. It is affected by factors like water content, mix proportions, aggregate size and shape, grading and surface texture. Increasing water content or using admixtures improves workability by acting as a lubricant between particles. Larger, rounded aggregates require less water than smaller, angular ones. Well-graded aggregates with minimal voids also increase workability. Workability can be measured using slump, compacting factor, flow, or Vee Bee tests.
This document provides an overview of the IRC method for designing flexible pavements according to IRC: 37-2012. It discusses the key considerations and calculations involved, including design traffic, subgrade properties like CBR and resilient modulus, material properties, and traffic data collection. The goal is to design a flexible pavement for a new four-lane divided national highway using the IRC guidelines and given traffic and material property data.
Concrete is the most widely used construction material in India with annual consumption exceeding 100 million cubic meters.
High performance concrete is a concrete in which certain characteristics are developed for a particular application and environment, so that it will give excellent performance in the structure in which it will be placed.
A high-strength concrete is always a high performance concrete, but a high-performance concrete is not always a high-strength concrete.
The document discusses concrete mix design, including:
- Concrete is made from cement, aggregates, water, and sometimes admixtures.
- ACI and BIS methods are described for determining mix proportions based on factors like strength, workability, durability, and materials.
- A step-by-step example is provided to design a mix using the ACI method for a specified 30MPa strength, including determining water-cement ratio, volumes, and final proportions.
This document discusses the compressive strength of concrete. It defines compressive strength as the ability of a material to withstand pushing forces. Concrete is strong in compression but weak in tension. The document describes how to test the compressive strength of concrete cube and cylinder specimens. It provides details on specimen size, curing, loading rate, and calculating compressive strength based on applied load divided by cross-sectional area.
Concrete permeability is a key factor in its durability. Permeability is affected by water-cement ratio, with lower ratios producing less permeable concrete. Curing also impacts permeability. Proper curing, including moist curing, produces less permeable concrete. Permeability testing involves measuring water flow through a sample over time under pressure. Sulfate attack can occur when sulfates penetrate permeable concrete and form expansive compounds that crack the material. Resistance to sulfates is improved with lower permeability concrete.
This document provides information on various tests conducted on aggregates that are used in construction. It describes the aggregate abrasion value test, which determines the abrasion resistance and hardness of aggregates. It also summarizes the aggregate impact value test, which evaluates the resistance of aggregates to shocks and impacts, and the aggregate crushing value test, which determines the resistance of aggregates to crushing under gradually applied compressive loads. Finally, it outlines the procedure to determine the specific gravity and water absorption of aggregates.
The document provides information on aggregates used in concrete, including their definition, classification, properties, grading, and tests. It defines aggregates as materials such as sand and gravel used to make concrete and mortar. Aggregates are classified by their geological origin, size, and shape. Their properties including strength, absorption, and density are described. The importance of proper grading of aggregates for density and strength of concrete is discussed. Common tests on aggregates like crushing value, impact value, and abrasion value are outlined.
Workability of concrete is defined as the ease and homogeneity with which a freshly mixed concrete or mortar can be mixed, placed, compacted and finished. Strictly, it is the amount of useful internal work necessary to produce 100% compaction.
This document discusses Ordinary Portland Cement and Rapid Hardening Cement. It defines cement and describes its main types. Ordinary Portland Cement (OPC) is the most widely used type and comprises calcium, silica, alumina, and iron. The production process involves crushing raw materials, mixing them, heating the mixture in a kiln to form clinker, grinding the clinker, and adding gypsum. OPC is used in construction where special properties are not required. Rapid Hardening Cement gains strength more quickly than OPC and is used when early strength or cold weather work is needed.
This document provides information about different types of cement used in construction. It discusses 6 main types:
1) Portland cement, the most common type used for its strength and availability.
2) Rapid hardening cement which gains strength faster but needs more water.
3) Super-sulphated Portland cement which has better water resistance and is used where exposed to sulphates.
4) Sulphate-resisting Portland cement for use in conditions with high sulphate levels like seawater.
5) Portland slag cement which has similar properties to ordinary Portland cement.
6) Portland pozzolana cement which has better chemical resistance and is used for marine construction.
The document provides information on a presentation about different types of cement. It discusses the definition and constituents of cement. It then covers the history of cement use in Nepal. The main types of cement discussed include Ordinary Portland Cement (OPC), Portland Pozzolana Cement, Rapid Hardening Cement, Extra Rapid Hardening Cement, Sulphate Resisting Cement, and others. For each type, the document outlines their manufacturing process, properties, and common uses.
Admixtures are materials added to concrete mixes to modify properties. There are two main types - chemical and mineral. Chemical admixtures include plasticizers, superplasticizers, retarders, accelerators, and air-entraining agents. Mineral admixtures include fly ash, slag, and silica fume. Admixtures are used to increase workability, strength, and durability while decreasing water demand and permeability. Common admixtures like plasticizers and superplasticizers work by dispersing cement particles and lubricating the mix to increase flowability.
The document discusses various aspects of tunnel engineering. It begins by introducing tunnels and their uses for transportation. It then discusses the Thames Tunnel in London as an example. The document outlines several advantages of tunneling over other methods. It also discusses considerations for selecting tunnel routes and economies of tunneling. The remainder of the document describes various tunneling methods through both rock and soft ground, as well as tunnel drainage, lighting, ventilation, lining, and maintenance.
Properties of fresh and Hardened ConcreteVijay RAWAT
The document discusses various properties of fresh and hardened concrete. It describes workability, consistency, segregation, bleeding, mixing, placing, consolidating, and curing of fresh concrete. It also discusses compressive strength, tensile strength, modulus of elasticity, permeability, and durability of hardened concrete. The key properties of fresh concrete include workability, consistency, segregation, bleeding, setting time, and uniformity. Compressive strength is identified as the most important property of hardened concrete.
This document discusses different methods for soil stabilization, including mechanical, physical, chemical, and bituminous stabilization. Mechanical stabilization involves compacting soil to increase density and strength. Physical stabilization involves blending soils or adding admixtures to improve properties. Chemical stabilization uses lime, cement, or other chemicals like calcium chloride to react with soils and modify their characteristics. Bituminous stabilization involves adding bitumen or asphalt to seal soil pores and increase cohesion between particles. The document provides details on appropriate soil types, required quantities, and construction methods for each stabilization technique.
This document provides details for estimating the cost of constructing a two room office building, including specifications, dimensions, and calculations. It begins by outlining the footing, floor, and roof details. It then provides a three step process for cost estimation: [1] excavation, [2] PCC (plain cement concrete) for foundations, and [3] calculating quantities of cement, sand, and aggregate required for the PCC based on the volume. Calculations are shown using the center line method to determine excavation and concrete quantities based on wall lengths and dimensions.
MEANING OF MIX DESIGN
GRADE OF CONCRETE.
FACTORS INFLUCING THE CHOICE OF MIX DESIGN.
MATHODS OF CONCRETE MIX DESIGN
MIX DESIGN BY INDIAN STANDARD METHOD.
Design of rigid pavements. IRC method of design of rigid pavement. Transportation Engineering. Civil Engineering. Wheel loads on rigid pavement. Action of various stresses on rigid pavement. Highway engineering. How rigid pavements different from flexible pavements
Workability refers to the ease with which fresh concrete can be mixed, placed, compacted and finished. It is affected by factors like water content, mix proportions, aggregate size and shape, grading and surface texture. Increasing water content or using admixtures improves workability by acting as a lubricant between particles. Larger, rounded aggregates require less water than smaller, angular ones. Well-graded aggregates with minimal voids also increase workability. Workability can be measured using slump, compacting factor, flow, or Vee Bee tests.
This document provides an overview of the IRC method for designing flexible pavements according to IRC: 37-2012. It discusses the key considerations and calculations involved, including design traffic, subgrade properties like CBR and resilient modulus, material properties, and traffic data collection. The goal is to design a flexible pavement for a new four-lane divided national highway using the IRC guidelines and given traffic and material property data.
Concrete is the most widely used construction material in India with annual consumption exceeding 100 million cubic meters.
High performance concrete is a concrete in which certain characteristics are developed for a particular application and environment, so that it will give excellent performance in the structure in which it will be placed.
A high-strength concrete is always a high performance concrete, but a high-performance concrete is not always a high-strength concrete.
The document discusses concrete mix design, including:
- Concrete is made from cement, aggregates, water, and sometimes admixtures.
- ACI and BIS methods are described for determining mix proportions based on factors like strength, workability, durability, and materials.
- A step-by-step example is provided to design a mix using the ACI method for a specified 30MPa strength, including determining water-cement ratio, volumes, and final proportions.
This document discusses the compressive strength of concrete. It defines compressive strength as the ability of a material to withstand pushing forces. Concrete is strong in compression but weak in tension. The document describes how to test the compressive strength of concrete cube and cylinder specimens. It provides details on specimen size, curing, loading rate, and calculating compressive strength based on applied load divided by cross-sectional area.
Concrete permeability is a key factor in its durability. Permeability is affected by water-cement ratio, with lower ratios producing less permeable concrete. Curing also impacts permeability. Proper curing, including moist curing, produces less permeable concrete. Permeability testing involves measuring water flow through a sample over time under pressure. Sulfate attack can occur when sulfates penetrate permeable concrete and form expansive compounds that crack the material. Resistance to sulfates is improved with lower permeability concrete.
This document provides information on various tests conducted on aggregates that are used in construction. It describes the aggregate abrasion value test, which determines the abrasion resistance and hardness of aggregates. It also summarizes the aggregate impact value test, which evaluates the resistance of aggregates to shocks and impacts, and the aggregate crushing value test, which determines the resistance of aggregates to crushing under gradually applied compressive loads. Finally, it outlines the procedure to determine the specific gravity and water absorption of aggregates.
The document provides information on aggregates used in concrete, including their definition, classification, properties, grading, and tests. It defines aggregates as materials such as sand and gravel used to make concrete and mortar. Aggregates are classified by their geological origin, size, and shape. Their properties including strength, absorption, and density are described. The importance of proper grading of aggregates for density and strength of concrete is discussed. Common tests on aggregates like crushing value, impact value, and abrasion value are outlined.
Workability of concrete is defined as the ease and homogeneity with which a freshly mixed concrete or mortar can be mixed, placed, compacted and finished. Strictly, it is the amount of useful internal work necessary to produce 100% compaction.
This document discusses Ordinary Portland Cement and Rapid Hardening Cement. It defines cement and describes its main types. Ordinary Portland Cement (OPC) is the most widely used type and comprises calcium, silica, alumina, and iron. The production process involves crushing raw materials, mixing them, heating the mixture in a kiln to form clinker, grinding the clinker, and adding gypsum. OPC is used in construction where special properties are not required. Rapid Hardening Cement gains strength more quickly than OPC and is used when early strength or cold weather work is needed.
This document provides information about different types of cement used in construction. It discusses 6 main types:
1) Portland cement, the most common type used for its strength and availability.
2) Rapid hardening cement which gains strength faster but needs more water.
3) Super-sulphated Portland cement which has better water resistance and is used where exposed to sulphates.
4) Sulphate-resisting Portland cement for use in conditions with high sulphate levels like seawater.
5) Portland slag cement which has similar properties to ordinary Portland cement.
6) Portland pozzolana cement which has better chemical resistance and is used for marine construction.
The document provides information on a presentation about different types of cement. It discusses the definition and constituents of cement. It then covers the history of cement use in Nepal. The main types of cement discussed include Ordinary Portland Cement (OPC), Portland Pozzolana Cement, Rapid Hardening Cement, Extra Rapid Hardening Cement, Sulphate Resisting Cement, and others. For each type, the document outlines their manufacturing process, properties, and common uses.
This slideset was prepared as a student group assignment, for a class on-Introduction to Construction Materials. The facts shown and data used are most relevant to the Indian Context. Prepared by- K. Hari Chandana, Sukirti Sah, Tanya Talwar, Rana Sarkar, Akriti Srivastava, Jitendriya Meher, Anshuman Abhisek Mishra : 1st Sem B. Arch, School of Planning & Architecture, Bhopal, MP, India
This document provides information on cement, including its composition, types, and testing methods. It discusses that cement is a binding material made by burning limestone and clay at high temperatures. There are different types of cement used for various purposes, such as rapid hardening cement, which sets faster. Cement is tested for properties like setting time, compressive strength, and tensile strength using methods like the Vicat apparatus and compressive testing machine. The document also covers cement hydration and how strength develops over time through the hydration process.
1. Special concrete refers to concrete made with special materials or techniques to achieve improved properties compared to normal concrete. Some examples are lightweight, high-strength, and fiber-reinforced concrete.
2. Special concretes are used for applications requiring reduced weight, increased durability, strength, or other optimized properties. Lightweight concrete for example reduces structural weight and is used in multi-story buildings.
3. Production methods vary depending on the type of special concrete but include using special aggregates, adding fibers or other materials, or applying processes like vacuum dewatering to improve properties. Each type has advantages and limitations for different construction needs.
A Compatibility Study on Different Types of Cement and Plasticizerijsrd.com
It has long been a concrete technologist's dream to discover method of making concrete at the lowest possible water/cement ratio while maintaining a high workability. To a considerable extent this dream has been fulfilled with the advent of super plasticizers. It has added a new dimension to the application of admixtures with regards to production of high strength and flow able concretes. It is now possible to produce concrete with compressive strength of the order of 90Mpa (90 N/mm2). In the wake of energy conservation policy and diminishing supplies of high quality raw materials, there is a need to use marginal quality cements and aggregates for the production of concrete. In such instances the use of plasticizers/super plasticizers permits the production of concrete at low water/ cement ratios. We have taken ultra tech opc cement & coromandal ppc cement to find the compatibility by adding perma plast (plasticizer). The water cement ratio was maintained as 0.40 &0.45 for OPC & PPC respectively. To study the effect of these PP on various properties of concrete. The dosage of plasticizers/super plasticizers was measured as 1.5% for Perma plast for OPC & 1.3% for PPC by the weight of cement.
Concrete Technology Introduction By DR. Vishwanath KantheBhavesh Bagul
The document discusses the key ingredients of concrete including cement, fine aggregate, coarse aggregate, and water. It provides details on the properties and testing of cement and aggregates.
Cement is the most important ingredient and is made by grinding raw materials like limestone and clay and burning them in a kiln. The chemical composition and hydration process of cement are described. Different types of cement like ordinary Portland cement and sulfate resisting cement are also mentioned.
The properties of aggregates like size, shape, texture and strength are outlined. Tests for properties like specific gravity, water absorption and sieve analysis are noted. The effect of aggregate size and shape on concrete properties is summarized.
- The document provides results analysis for an Advance Concrete Technology course from 2015-16, 2017-18, and 2018-19 academic years. It shows the number of students, percentage who passed/failed, and average marks for each year. The pass percentage was highest in 2018-19 at 100%.
- The syllabus, course content, and practical sessions for the Advance Concrete Technology course are outlined over 7 units covering topics like concrete ingredients, modern concrete types, mix designs, non-destructive testing, fiber reinforced concrete, ferrocement, and prefabrication.
- Cement manufacturing processes, types of cement, and their properties and uses are discussed in detail.
Concrete is the most widely used construction material due to its durability, affordability, and ability to be cast into any shape. A proper concrete mix design targets compressive strength, workability, durability, and quality control. The key aspects of mix proportioning include selecting aggregates based on properties like composition and size, using an optimized gradation, and determining the right water-cement ratio to achieve the desired strength and minimize waste. Chemical admixtures can be added to improve properties like freeze-thaw resistance or to accelerate or retard setting times for different construction needs.
This document provides an overview of cement, including its history, main chemical compounds, properties, hydration process, setting, and types. It discusses how Joseph Aspdin first produced Portland cement in 1824 and how cement production has expanded globally. The four main compounds in Portland cement are tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite. The document also examines cement's physical properties like fineness and strength, as well as the hydration and setting processes. Different cement types include ASTM Types I-V as well as masonry cement and natural cement.
CEMENT , TYPES OF CEMENTS , PORTLAND CEMENT
TYPES OF PORTLAND CEMENT, GENERAL FEATURES OF THE MAIN TYPES OF PORTLAND CEMENT, ORDINARY PORTLAND CEMENT (OPC), RAPID HARDENING PORTLAND CEMENT, SPECIAL TYPES OF RAPID HARDENING PORTLAND CEMENT, MANUFACTURE OF PORTLAND CEMENT, Raw Materials, Crushing & Grinding of Raw Materials,Type of cement processes, Wet Process, Dry process, Burning Process, Grinding, storage, packing, dispatch,CEMENT CHEMISTRY,Chemical Compositions,Bogue’s Equations, Fineness of cement
The document provides information about construction materials used in concrete. It discusses the key materials used including cement, mineral admixtures like fly ash and GGBFS, aggregates, and water. It describes the composition and properties of common cement types like ordinary Portland cement, Portland pozzolana cement, Portland slag cement, and sulfate resisting cement. It also discusses admixtures used in concrete including accelerators, retarders, water reducers, and superplasticizers.
This document provides information on cement including field testing methods, physical properties like setting time, soundness, fineness, and strength. It describes how these properties are tested using methods like the Vicat apparatus, Le Chatelier test, and compressive strength testing. It also lists and describes various types of cement specified in Indian standards like ordinary Portland cement, rapid hardening cement, sulphate resisting cement, and Portland pozzolana cement.
The document provides information on the chemical composition and typical oxide composition percentages of raw materials used to make cement. It states that lime (CaO) ranges from 60-65% and controls strength and soundness. Silica (SiO2) ranges from 17-25% and excess causes slow setting. Alumina (Al2O3) ranges from 3-8% and is responsible for quick setting, with excess lowering strength. Iron oxide (Fe2O3) ranges from 0.5-6% and gives color and helps fuse ingredients. Magnesia (MgO) ranges from 0.1-4% and gives color and hardness. Soda and potash (Na2O and K2O)
Portland cement concrete is an artificial rock composed of aggregates, water, and a cementing agent like Portland cement. Portland cement is produced by burning and grinding a mixture of limestone, silica, alumina, and iron. The major constituents of Portland cement are compounds like C3S, C2S, C3A, and C4AF that form during burning and fusion and influence properties like strength. Concrete is composed of cement, water, fine aggregate, coarse aggregate, and sometimes admixtures. Admixtures are added during mixing to improve properties and aid construction. Curing protects concrete from moisture loss and temperature extremes to ensure proper strength development.
Here are the steps to solve this nominal mix design problem based on mass:
1) Given: Cement mass = 150 kg
Mix ratio = 1:2:4
Densities:
Cement = 1440 kg/m3
Fine aggregate = 1640 kg/m3
Coarse aggregate = 1390 kg/m3
2) Calculate cement volume:
Cement mass / Cement density = Volume
150 kg / 1440 kg/m3 = 0.104 m3
3) Calculate fine aggregate volume based on mix ratio:
Cement volume x Fine aggregate ratio = Fine aggregate volume
0.104 m3 x 2 = 0.208 m3
Cement class 12 notes of cement chapter.pdfSafalPoudel6
Cement is produced through a process involving crushing and grinding raw materials such as limestone and clay, heating the materials in a kiln to form clinker, cooling and grinding the clinker, and adding gypsum. The main raw materials used are limestone, clay, iron oxide, and aluminum oxide. During the heating process in a rotary kiln, the raw materials undergo chemical reactions to form calcium silicates and calcium aluminates which fuse together to form clinker. Gypsum is added to the ground clinker to regulate the setting time of cement.
Chapter 5 plain and reinforced cement concrete constructionKHUSHBU SHAH
This document discusses the key ingredients and properties of reinforced cement concrete (RCC). It describes cement, aggregates, water, and steel reinforcement bars as the main ingredients. Cement acts as the binding agent. Fine and coarse aggregates provide structure and strength. Water enables the chemical reactions during curing. Steel reinforcement bars provide tensile strength to counteract the low tensile strength of concrete. The document also discusses different types of cement used for RCC, including their compositions and purposes. Testing methods for cement such as fineness, setting time, strength, and soundness are also summarized.
Construction Materials and Engineering - Module IV - Lecture NotesSHAMJITH KM
The document discusses various basic components of building construction including substructure, superstructure, foundation, plinth, beams, columns, walls, arches, roofs, slabs, lintels, parapets, staircases, doors, windows and other elements. It provides descriptions of each component, their functions and materials typically used. Foundations discussed include isolated spread footing, wall/strip footing, combined footing, cantilever/strap footing and mat/raft footing for shallow foundations and pile, well/caisson and pier foundations for deep foundations. Flooring materials and requirements are also summarized along with technical terms for doors and windows.
Construction Materials and Engineering - Module III - Lecture NotesSHAMJITH KM
The document discusses various construction materials and methods. It covers topics like masonry, bricks, stone masonry, types of bonds, hollow block masonry, partition walls, modern construction methods, and damp proof courses. Masonry involves arranging masonry units like stone or bricks with mortar. There are different types of bonds used in brick masonry like stretcher bond, header bond, English bond and Flemish bond. Modern methods include framed construction, prefabricated construction and earthquake resistant construction. Damp proof courses are provided to prevent entry of moisture into buildings.
Construction Materials and Engineering - Module II - Lecture NotesSHAMJITH KM
This document provides information on various construction materials including paints, plastics, rubber, and aluminum. It discusses the ingredients, properties, types, and applications of paints. It also outlines the classification, characteristics, uses, advantages, and limitations of plastics. Details are provided on types of rubber like natural and synthetic rubber. Applications of aluminum in construction are also mentioned.
Construction Materials and Engineering - Module I - Lecture NotesSHAMJITH KM
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Concrete Technology Study Notes
1. DIPLOMA IN CIVIL ENGINEERING
CONCRETE TECHNOLOGY – STUDY NOTES
MODULE I
1. What is cement? What are its important properties?
Any material that can acts as a binding agent for materials.
o Have good Adhesive and cohesive property
o On adding water Hydration takes place
o Initial setting time for OPC = 30 minutes
o Final setting time for OPC = 10 hours/600 minutes
o Normal consistency = 26 -33 %
2. List types of cement and explain briefly?
Various types of cement used are:
1. Ordinary Portland Cement (OPC)
o 33 Grade, 43 Grade, and 53 Grade – 33 = fck
2. Rapid Hardening cement (RHC)
o Develop early strength – 3 days (OPC – 7 days)
o High C3S content, Low C2S content.
o Higher fineness
o Uses: Prefabricatedconstructions, roadrepair works, coldweather
3. Extra Rapid Hardening Cement
o RHC + CaCl2 (by 2 % weight of RHC)
o Mixing, placing, compactionand finishing within 20 minutes
o Storage time – 1 month
o Not discussed in IS Code
o Uses: Cold weather, under waterconcreting
4. Sulphate Resisting Cement
o To resist sulphate attack
o Volume of concrete increases due to reaction of cement with sulphate
containing solution.
o Ca(OH)2 + CaSO4 Volume increases by 227 %
o Uses: Marine structures, foundations, sewagetreatmentunits,
hydraulic structures
5. Portland Slag cement
o Slag = OPC clinker + Blast furnace slag + Gypsum
o Resistant to chemical attacks:
Sulphate attack, Acid attack, Alkali attack, Chlorides attack
o Reduced permeability
o Uses: Mass concreting, dams, etc
6. Quick setting cement
o Quick setting property
2. 7. Super Sulphated cement
8. Low heat cement
9. Portland Pozzolano Cement (PPC)
o OPC Clinker + Pozzolanic material (15-35%)+ Gypsum PPC
o OPC + Ca(OH)2 + Water C-S-H gel (Calcium-Silicate-Hydrate)
o PPC gives increased volume than OPC
o Pozzolanic material is cheaper
o Long term strength higher than OPC
o Disadvantage - Reduced alkalinity leads to corrosion
o Disadvantage – Initial development of strength is slower than OPC
10.Air Entraining cement
11.Coloured cement/White cement
12.Hydrophobic cement
13.Masonry Cement
14.Expansive cement
15.High Alumina Cement
16.Very High Strength Cement
o Used in prestressed concrete works
3. What are the functions of cement ingredients? Explain.
Ingredients in concrete and functions:
4. Explain the methods of storing cement.
Methods of storing cement:
1. Jute or gunny bags
2. Storage period = 3 months
3. Stacked in 10 bag piles
4. Care to maintain quality – no moisture content
5. Remove cement bags in order
6. Label – date of receipt – to find age of cement
7. Use waterproof shed/polyethylene during monsoon.
5. What are the functions of alumina in cement?
3. o Imparts quick setting property to the cement.
o It acts as a flux and it lowers the clinkering temperature.
o Excess alumina weakens the cement.
6. What is heat of hydration? How the heat of hydration affects in mass
concreting?
o Chemical reaction between cement and water HYDRATION
o Stages ofhydration:
1. Loss of workability
2. Setting (Solid Concrete)
3. Hardening (Strength gain)
o EXOTHERMIC REACTION Liberates considerable quantity of heat.
o The heat produced during the chemical reaction of cement with water is termed
as HEAT OF HYDRATION.
Mass concreting and heat of hydration:
o Large amount of heat is produced during first few days of mass concrete works.
Eg: Dam.
o Max temperature within 1-3 days.
o Heat is trapped and cannot escapequickly.
o Results in thermal cracking.
o Concrete mix becomes too hot.
7. Explain the chemistry of hydration of cement
Cement + Water C-S-H gel + Heat
Bougue’s compounds:
Reaction of Bougue’s compounds:
4. Reaction with gypsum:
8. Write the functions of hydrated compounds such as C3S, C2S and Ca(OH)2.
2 C3S + 6 H C3S2H3 + 3 Ca(OH)2 + ∆(𝒉𝒆𝒂𝒕)
2 C2S + 4 H C3S2H3 + Ca(OH)2 + ∆
C3S Early strength contribution
C2S Final strength contribution
Ca(OH)2 Breakdown of Portland cement
9. Explain the field tests for cement?
Field tests of cement:
o Open the bag and take a good look at the cement - no visible lumps.
o Colour = Greenish grey
o Should get a coolfeeling when thrusted
o When we throw the cement on a bucket full of water, before it sinks the particle
should flow
10. What is mean by bulking of sand?
Increase in volume of fine aggregates due to presence of water (moisture content)
Fine sand bulks more than coarsesand.
Coarse aggregate does not bulk
When water is added to dry sand, a film forms around each sand particle. Thus volume
increases. When more water is added, the water films break and thus volume
decreases. The volume of dry sand increases due to absorption of moisture. This is
called as bulking of sand.
11. Differentiate betweenuniform grading and gap grading.
Poorly graded All particles of aggregate have same size – more voids
Well graded Contains particles of all sizes (GOOD)
Gap graded Some big, some small particles.
5. 12. What is characteristic compressivestrength?
Compressive strength is imp property of hardened concrete.
Compressive strength is given in terms of characteristic compressive strength of 150
mm size cubes tested at 28 days.
Defined as strength of concrete below which not more than 5 % of test results are
expected to fall [IS 456:2000].
Follows NORMAL DISTRIBUTION
13. Write a note on sulphate resisting Portland cement and low heat Portland
cement?
Sulphate Resisting Portland Cement:
o Resistant to sulphate attack
o low C3A content (5 % only)
o
Uses: Sewage treatment works, marine structures
Low heat cement:
o Low C3S and C3A
o Slow rate of gain of strength
o Same ultimate strength of OPC
Uses: Dams, mass concrete works
14. Name any four mineral admixtures using for blended concrete?
Blended concrete = OPC + Mineral admixtures
Mineral admixtures – Hydraulic/ pozzolanic activity
To make concreteeconomical
Examples for Mineral admixtures
Fly ash
Silica fume
Rice Husk Ash
Metakaolin
Ground granulated blast furnace slag (GGBFS)
6. 15. Name any four admixtures using for concrete mixes?
Chemicals added to concrete before or during mixing of concrete to modify some
specific property of fresh or hardened concrete.
Examples are :-
1. Super plasticizer
2. Accelerators
3. Retarders
4. Air entraining admixtures
5. Water-reducers
16. Write a note on (i) Admixtures (ii) Accelerators (iii) Retarders
Admixtures:
o Chemicals added to concrete before or during mixing of concrete to modify
specific property of fresh or hardened concrete.
o Available in powder and liquid form.
1. Accelerating admixtures
2. Retarding admixtures
3. Water reducing admixtures
4. Air Entraining admixtures
Functions of admixtures:
Speed up rate of development of strength at early days
To keep the concrete workable for longer time
To enhance the workability
To improve penetration and pump ability of concrete
To reduce segregation
To increase strength
To decrease capillary flow of water
To control alkali aggregate reaction
To reduce the heat of hydration
To enhance bond between concrete and steel
To reduce weight of concrete, etc.
Accelerators:
o A type of admixture
o Increase rate of hydration of cement
o Reduce setting time
o Increase rate of strength development. Eg:- Na2SO4, NaCl, K2SO4, CaCl2
Retarders:
o To delay or reduces the setting time
o Slow rate of hydration
o Helpful – concrete transporting to long distance
o Eg:- Derivatives of Sugar and carbohydrates, gypsum, plaster of paris, etc
7. 17. What is soundness of cement? How is it tested?
Soundness test: Ability of hardened cement paste to retain its volume after setting
without expansion.
Reason:insufficiency in grinding, burning, etc.
Ensures:Cement does not undergo any large expansion and To detect the presence of
excess lime in cement.
o Expansion should be less than 10 mm
o OPC – Ordinary Portland Cement
o RHC – Rapid Hardening Cement
o Low Heat Portland Cement
o If expansion of cement > 10 mm
o Unsound
o Excess lime Cracks
18. Explain the classificationofaggregates?
8. 19. Write any six tests for coarse aggregateswhich determine the properties required
for mix design.
1. Aggregate crushing strength
2. Aggregate impact test
3. Abrasion test
4. Flakiness test
5. Elongation test
6. Sieve Analysis
MODULE II
1. Define concrete andwrite down its properties?
o Concrete is a composite mixture of CA + FA + water + Cement + Admixtures
o Unit weight = 25 kN/m3.
o Compressive strength: M20 : MMix, 20 Compressive strength
o Flexural strength, fcr = 0.7√fck
o Elastic deformation, Ec = 5000√fck
2. What are the ingredients of concrete andtheir fucntions?
Cement - Binding material
Coarse aggregate - Strength contribution
Fine aggregate - Void filler
Water - Hydration, workability, curing
Admixtures - to modify any specific properties.
3. Write the functions of sand in mortar.
Functions of sand in mortar:
o Void filler
o Bulking – Sand bulks volume of mortar increases Thus costreduced.
o Setting – setting of fat lime occurs effectively due to sand.
o Shrinkage – sand prevents excessive shrinkage of mortar and prevent cracking.
o Strength – helps in adjustment of strength by varying its proportion.
4. Explain the stress straincharacteristicsofconcrete?
9. Max compressive stress = 0.67 x characteristic cube strength
Design stress-strain curve of concrete:
5. What is segregationin concrete? How it is prevented?
Separation of constituent materials of concrete mix so that the mix is no longer in
homogenous condition. Types:
CA separating out / settling down from mix
Paste separating out away from CA
Prevention:
o Concrete mix should be properly designed with optimum quantity of water
o Field quality controlmust be maintained while handling, transporting, placing
& compacting and finishing concrete.
o If at any stage segregation is observed, then remixing should be done to make
the concrete again homogeneous.
o Admixtures, suchas pozzolanic materials or air entraining agent should be used
to avoid segregation
o Concrete should not be allowed to fall from greater heights. It should be placed
as near its final position as possible.
6. What is curing? What is the necessityof curing?
Process ofpreventing the loss of moisture from the concrete whilst maintaining a
satisfactory temperature.
Reasonsto cure concrete
Gain of strength in concrete by hydration
Improved durability of concrete
Improved serviceability and to improvement in microstructure of concrete
To avoid loss of moisture, curing is required
Prevents concrete from cracking
Methods of curing
Ponding
Sprinkling
Wet coverings
Membrane/Plastic sheet curing
Steam curing
10. Water based curing
7. How is the consistencyofcement paste tested?
o Consistency refers to the relative mobility of a freshly mixed cement paste or
mortar or its ability to flow.
o The property of holding together and retaining shape.
o Consistency which will permit a vicat plunger to penetrate a depth of 33-35 mm
from top of the mould.
o Measured using Vicat Apparatus.
Procedure:
o Take 400 g cement
o Add 25 % water by weight of dry cement
o Make a paste and fill in the vicat mould.
o Release the vicat needle and measure penetration.
o Note the water content added when vacat penetrates 33-35 mm.
o Generally normal consistency for OPC ranges from 26 to 33%.
8. What is super plasticizer? When and where super plasticizers are used?
o A type of water reducing admixture.
o Also called as High range water reducer.
o Increased fluidity : flowing, self levelling, etc.
o Reduced water cement ratio: High early strength.
Commonly used superplasticizers are:
Sulphonated melamine formaldehyde condensates (SMF)
Sulphonated naphthalene formaldehyde condensates (SNF)
Polycarboxylate ether superplasticizers (PCE)
9. What are the methods of transporting concrete?
Transporting and placing is done using:
o Mortar pan
o Wheelbarrows and Buggies
o Belt Conveyors, Cranes and Buckets
o Pumps and Transit Mixer
o Truck mixer and dumper
11. o Chutes, Pumps and pipelines
o Helicopter.
10. What are the factors affecting strength of the concrete?
11. What are the tests for measuring workability of concrete?
Workability of concrete is measured using
Slump test
Compaction factor test
Vee-bee consistometer test
Flow test
12. Discuss briefly about various methods of compacting concrete?
To expel entrapped air from the concrete.
1% air in the concrete approximately reduces the strength by 6%.
If we don’texpel this air, it will result into honeycombing and reduced strength.
13. Explain the flakiness index and elongationindex.
Flakiness Index: % by weight of particles whose least dimension (thickness) is less
than 3/5 (0.6) of their mean dimension.
12. Elongation Index: % by weight of particles whose greatest dimension (length) is
greater than 1.8 times their mean dimension.
The Indian Standard do not specify limits for flakiness index and elongation index but
generally flakiness index shall not exceed 40 % and the elongation index shall not
exceed 15 %.
14. Explain the role of watercement ratio in the strength of concrete.
Water-cement ratio: Ratio of mass of ‘free water’ (excluding that absorbed by
aggregates) to cement in a mix.
o Range: 0.35 – 0.65
o Most important indicator of strength.
o Low w/c ratio Higher strength
o Low w/c ratio is good
Abram’s Law :
Water-cement ratio is inversely proportional to compressive strength of concrete.
15. Explain the testfor alkaliaggregate reactionin concrete.
Alkali-aggregate reaction
Known as ‘ConcreteCancer’.
Expansion of concrete Volume increases Swelling/Bulging
Cracks forms Strength reduces
Factors affecting Alkali-aggregate reaction:
o High alkali content in cement.
o Reactive silica or carbonate in aggregates.
o Availability of moisture.
13. o Temperature = 350C.
Remedial measures:
o By using low alkali content cement.
o Selecting non reactive aggregates.
o By controlling moisture and temperature.
o By using pozzolanas, slags, silica fumes, etc.
o By using air entraining agents
16. Explain the factors affecting workability of concrete. Explain
Property of freshly mixed concrete which determines the ease and homogeneity with
which it can be mixed, placed, compacted and finished.
It is the ability of concrete to flow and work with concrete.
Property of concrete which determines the amount of useful internal work necessary to
producefull compaction.
Factors affecting Workability of concrete
Influence of mix proportion
o Amount of water, aggregates, admixtures, etc
Influence of aggregate properties
o Specific surface area (SSA), shape and size, etc
Influence of admixtures
o Plasticizers, super plasticizers, etc
Effect of Environmental conditions
o Temperature, freezing, thawing, etc
Effect of time – Evaporation
In short, factors affecting are
Cement content
Water content
Mix proportions
Size of aggregates
Shape of aggregates
Grading of aggregates
Surface texture of aggregates
Use of admixtures in concrete
Time and environmental conditions
17. Explain slump test? What are the different types of slump?
Test to determine workability of concrete.
Field and lab test.
Types of slump
o True slump
o Shear slump
14. o Collapse slump
Procedure:
o Prepare mix and fill slump cone.
o Layer 1= 25 tamping
o Layer 2 = 25 tamping
o Layer 3 = 25 tampngs
o Cut the excess concreteand level the top
o Take the slump cone
o Measure the slump : Max = 300 mm
18. How compactionfactortest is conducted?
Test to determine workability of concrete.
Field and lab test
Procedure:
o Prepare mix
o Fill in HOPPER A
o Open trap door Mix falls to HOPPER B
o Open trap door Mix falls to CYLINDER
o Weight it Weight of partially compacted concrete.
o Remove all concrete from cylinder – EMPTY IT
o Again fill the cylinder from same sample mix
o Fill in 3 LAYERS – 25 Tampings with tamping rod
o Weight it Weight of fully compacted concrete
Compaction Factor,
15. 19. Explain vee-bee test?
To determine workability of concrete Indirectly.
Lab test
Procedure:
o Slump cone placed inside cylinder
o Swivel glass is turned & placed on slump cone
o ON the vibrator + Start stop watch
o Conical shape of slump disappears Flat
o OFF the stop watch
o The time taken is noted Vee bee seconds
20. Explain the factors influence the durability of concrete.
Durability:
o Time for which the structure can fulfil its desired objectives.
o Ability to withstand the damaging effects over a long time.
o Resistance to deterioration.
o Deterioration may be due to internal or external factors.
o Internal factors are - b/w constituent materials and contaminants.
o External factors – interaction with environment.
Factors affecting durability:
o Permeability
o Frostaction
o Suplhate attack
o Mineral oils
o Organic acids
o Vegetables & animal oils and fats
o Sugar
o Sewage
o Thermal effects on concrete
o cracks
21. What are the advantages and disadvantages ofsuper plasticizer in concrete?
Advantages:
o Significant water reduction.
o Reduced cement contents and Increased workability.
o Reduced effort required for placement.
o More effective use of cement.
o More rapid rate of development of strength.
o Increased long term strength and Reduced permeability.
Disadvantages:
o Additional admixture cost
16. o Slump loss greater than conventional concrete.
o Modification of air entraining dosage.
o Less responsive with some cement.
o Mild decoloration takes place.
22. Describe the importance of quality of waterused for concreting?
Functions of water in concrete:
o Potable water (drinking water can be used) is used in concrete.
o Amount of water controls Workability of concrete.
o Amount of water controls Hydration.
o Amount of water controls Curing.
o Affects strength of concrete.
o Affects shrinkage of concrete.
23. What are tests on hardened concrete?
1. Compressiontest (cube & cylinder)
2. Flexural strength test
3. Split tensile strength test
24. Compare cylinder test and cube test in concrete compression.
25. Define shrinkage and creep. What are the factors affecting shrinkage and creep?
Creep:
o Time dependent deformations of concrete under permanent loads.
o Time dependent strain due to self weight.
o Permanent deformation with time at constant loading.
o Plastic deformation (Permanent and non-recoverable).
o Homologous temp – temperature at which creep is uncontrollable.
o Continuous deformation of concrete with time under sustained load.
Shrinkage:
o Shortening of concrete due to drying (loss of moisture).
o Contraction due to loss of moisture.
o Evaporation of water from concrete mixture leads to loss of moisture.
o Plastic deformation (Permanent and non-recoverable).
o Homologous temp – temperature at which creep is uncontrollable.
o Continuous deformation of concrete with time under sustained load.
17. 26. Explain briefly on the properties of hardened concrete?
Properties of concrete in the hardened state:
1. Strength
o Resistance offered by concrete against failure
o Primary design parameter
o Strong in compression, weak in tension.
o Types of strength: Compressive, tensile, shear, bond, impact and fatigue
o Tensile strength = 10 % X Compressive stress
o Bending strength = 15 % X Compressive strength
o Shear strength = 20 % X Compressive strength
2. Stiffness
o Resistance of concrete against deformation
o Secondarydesign parameter
o Rigidity of an object
3. Poisson’s ratio
o When a material is stretched in one direction, it tends to get thinner in
other two directions.
o Ratio of lateral strain to longitudinal strain
o Normal concrete : 0.15 – 0.20
o Found by:
Strain measurements
Ultrasonic pulse velocity method
4. Fatigue
o Weakening of materials due to repeated cyclic loads
o Due to repeated loading and unloading
o If total accumulated strain energy exceeds toughness = FAILURE
o Microscopic cracks develops where stress concentration occurs.
o Life of the material decreases
5. Impact
o Sudden loading on a material
o High force or shock applied for a short time
6. Elasticity
o When a force is applied, material deforms.
o The property of a material to regain its original shape even after loading
is termed as elasticity.
o Concrete is not a perfectly elastic material
o Modulus of elasticity of concrete is determined by cube test
7. Modular ratio
18. o Ratio of modulus of elasticity of steel to that of concrete
8. Creep
o Time dependent deformations of concrete under permanent loads
o Time dependent strain due to self weight
o Permanent deformation with time at constant loading
o Plastic deformation (Permanent and non-recoverable)
o Continuous deformation of concrete with time under sustained load
9. Shrinkage
o Shortening of concrete due to drying (loss of moisture)
o Contraction due to loss of moisture
o Evaporation of water from concrete mixture leads to loss of moisture
10.Bond strength
o Strength between rebar and concrete
o Depends on surface configuration of rebar and concrete
o Ensures there is no slip of steel bar from concrete
o Develops primarily due to friction b/w rebar and concrete
o In general, bond strength proportional to compressive strength
11.Durability
o Time for which the structure can fulfil its desired objectives
o Ability to withstand the damaging effects over a long time
o Resistance to deterioration
o Deterioration may be due to internal or external factors
o Internal factors are - b/w constituent materials and contaminants
o External factors – interaction with environment
12.Brittleness
o Materials which fails suddenly
o Oppositeof plasticity
o Breaks before it deforms
o NOTE: Concrete is brittle
27. Describe compressiontest?
Procedure:
1. Prepare mix and fill in mould: 3 cubes – 15 X 15 X 15 cm
or 3 cylinders – dia=30 cm, 60 cm
2. Mould removal – after 1 day
3. Curing – 3, 7, 28 days
4. Tested using UTM (Universal Testin Machine) /
CTM (Compression Testing Machine)
19. 28. Describe the testcarried out to determine the flexural strength of concrete?
o To determine the tensile strength of concrete
o Flexural strength test procedure:
o Prepare mix and fill in mould
o Take Beam mould: 15X15X70 cm
o Tamp using tamping bar
o Test in Flexural testing machine
o Loading rate = 400 kg/min
o Flexural strength or modulus of rupture (fb)
29. Explain split tensile strength of concrete?
o To determine tensile strength of concrete
o Diameter = 15 cm, Height = 30 cm
o Tested using UTM
o Draw diametrical lines on two ends
o Note weight and dimension of specimen
o UTM Plywood strips on either sides
o Align the specimen
o Apply load (Rate = 14-21 kg/cm2/minute)
o Note breaking load
o As per IS 456, split tensile strength of concrete.= 0.7 fck
30. What is bleeding in concrete?
o Appearance of water along with cement particles on the surface of freshly laid
concrete.
o Tendency of water to rise to surface of freshly laid concrete.
o Particular form of segregation
o Reason : Water has low specific gravity than other contents
o Source: Over limit of compacting
o Quality and strength affected
31. Explain the methods of curing?
Curing :
o Process ofpreventing the loss of moisture from the concrete while maintaining
a satisfactory temperature.
20. o Concrete gain strength by hydration.
o To avoid loss of moisture
o Prevents concrete from cracking
Reasons:
o Gain of strength in concrete
o Improved durability of concrete
o Improved serviceability
o Improvement in microstructure of concrete.
Methods:
o Ponding
o Sprinkling
o Wet coverings
o Membrane/plastic sheet
o Steam curing
o Water based
32. Explain the different modulus of elasticity of concrete.
Elasticity:
When a force is applied, material deforms.
The property of a material to regain its original shape even after loading is termed as
elasticity.
Concrete is not a perfectly elastic material.
Modulus of elasticity of concrete is determined by cube test.
o Modulus of elasticity: Slope of straight line portion of stress-strain diagram.
o Initial tangent modulus : Modulus drawn from the first tangent.
21. o Secantmodulus: Slope of line connecting a specified point to the origin.
Modulus of elasticity commonly used in practice is secant modulus
MODULE III
1. What is concrete mix design? What are the various methods of mix design?
Mix Design is the art and science of determining the relative proportions of the
ingredients of concrete to achieve the desired properties in the most economical way.
To find a good combination of ingredients for concrete.
Should satisfy the required specifications
o Durability
o Structural Strength
o Workability – Mixing, placing, compacting and finishing.
It should be economical.
Methods of proportioning (Mix design):
o IS Method
o ACI Method
o Road Note-4 Method
o IRC-44 method
o Arbitrary method
o Max density method
o Fineness modulus method
o Surface area method
o Mix design for high strength concrete
o DOE mix design method
2. Explain the ideas/choicesbehind the mix proportioning.
Principles of Mix Design (Design requirements):
22. 3. Define (i) Meanstrength (ii) Variance and (iii) Standard Deviation
(1) Mean strength:
(2) Variance: Difference between any single observed data from the mean strength or
deviation from mean value.
(3) Standard deviation:
(4) Coefficient of variation:
4. What do you mean by targetstrength in concrete mix design.
5. Explain the relationbetweencharacteristic strengthand targetstrength of
concrete.
(Table 1, IS 10262:2009, page – 2)
S – standard deviation
6. Write the steps involved in the mix designas per IS 10262:2009.
See IS 10262:2009 and write
A-1 Stipulations for proportioning
A-2 Test data for materials
A-3 Target strength for mix proportioning
A-4 Selection of water cement ratio
A-5 Selection of water content
A-6 Calculation of cement content
A-7 Proportionof volume of CA and FA content
A-8 Mix calculations
A-9 Mix proportions for trial no.1
23. A-10 Do if needed
A-11 Do if needed.
MODULE IV
1. What is specialconcrete?
Concrete prepared for specific purpose.
Eg:-
o Light weight
o High density
o Fire protection
o Radiation shielding
2. Compare ordinary and specialconcrete.
3. List various types of specialconcrete.
1) Light weight concrete
2) Air entrained concrete
3) High Strength concrete
4) High performance concrete
5) Polymer concrete
6) Geo Polymer concrete
7) Steel fiber reinforced Concrete
8) Sulpher concrete
9) Self compacting concrete
10)No-fines concrete
11)Pre-packed concrete
12)Guniting or shotcreting
4. What is light weight concrete?Write advantagesoflight weight concrete?
Making concrete light weight by inclusion of air in concrete.
Three ways:
o Replace aggregate with cellular porous/LWA
= Light weight aggregate concrete
24. o Introduce gas/air bubbles in concrete
= Aerated concrete
o By omitting sand fraction from aggregates
= No fines concrete
Advantages:
o Reduction of self weight (Dead Load)
o Less haulage and handling costs
o Low thermal conductivity – Comfort – A/C
o Smaller section of structural members can taken
o Increase in the progress of work
o Good fire resistance
o Overall economy
5. What is air entrained concrete? Write its applications?
o Also called as Aerated concrete, gas concrete
o By introducing gas/air bubbles into a slurry
o Density 300-800 kg/m3.
o Self weight is reduced
o Applications:
o Insulation purposes
o Building blocks for load bearing walls
o Pre fabricated structures
6. What is high strength concrete (HSC)? What are its advantages?
Have higher compressive strength
High cement content, less w/c ratio
Methods:
o Seeding
o Revibration
o Using admixtures
o Sulphur impregnation
Applications
o Used mainly in pre-stressed concrete
o High rise buildings, long span bridges
7. Differentiate betweenHPC and HSC?
25. HPC HSC
High Performance Concrete High Strength Concrete
high abrasion resistance Strength 70 MPa or more
Good compactionwithout segregation A high-strength concrete is always a high-
performance concrete, but a high-
performance concrete is not always a
high-strength concrete.
Sensitive to changes in constituent
material
Where architectural considerations are
required.
High cementitious content and a water-
cementitious material ratio of 0.40 or less
Early high strength
Ease of placement and consolidation
without affecting strength
Toughness is good
Long-term mechanical properties Volume stability is high
8. Define corrosionin concrete? Whatare the protective measures takenagainst
corrosion? Explain the causes ofcorrosionof reinforcement.
Steel reinforcement inside the concrete get affected due attack of certain reactive
liquids and gases. This is termed as corrosionin concrete.
Eg:- Sewage pipelines, bridges, etc.
Causes ofcorrosion:
o Quality of concrete
o Cover thickness of concrete reinforcement
o Condition of reinforcement
o Effect of environmental and other chemicals
o Porosity of concrete
o Age of concrete
o Degree of compactness
o The size and grading of aggregate
o Type of cement
o Salt water causes corrosion.
o Effect of high thermal stress
o Freezing and thawing condition
Protective measures:
1. Improving the quality of concrete
Adopting the bestmix proportion
Efficient compaction during casting
Leak proofformwork
Adopting salt free sand
Using plasticizers
Using sulphate resisting cement and pozzolana cement
2. Increasing depth of concrete cover to reinforcement
3. Concrete coating and sealers
4. Galvanizing
26. Cathodic protection.
Anodic protection
5. Fusion bonded epoxycoating (fbec)
6. Coating of rebars
Paint
Chemical compound
Metallic epoxy coating
Fusion bonded epoxy
7. Properstorage & stacking of reinforcing steel
8. Use of corrosioninhibitors
9. Bio-film coating
10.Surface treatment
11.Selection of proper materials
9. Write short notes on (i) Sulphate attack (ii) Carbonation
Sulphate attack:
o Found in ground water and sub soil.
o Increase in volume of cement paste in concrete due to presence of sulphur
containing chemicals.
o In hardened concrete: Calcium-Aluminate-Hydrate (C-A-H) react with sulphur
salt to form calcium sulphoaluminate which increases volume of concrete upto
227 %.
o How to control sulphate attack?
o Use of sulphate resisting cement
o Addition of pozzolano.
o Quality of concrete
o Use of air entrainment
o High pressure steam curing
o Use of High-alumina cement
Carbonation:
o Alkalinity of concrete
o Carbon dioxide from the air reacts with Ca(OH)2 in concrete to form CaCO3.
o In the presence of moisture, carbonic acid is formed which reduces the
alkalinity of concrete.
o Thus PH value of concrete reduces (13.5 to 8.3).
o So corrosion increases.
10. Write short note on workability testin self-compacting concrete?
o Self compacting concreteshould have below properties.
1. Filling ability
2. Passing ability and
3. Segregation resistance
27. o The self compacting concrete must meet the filling ability and passing ability
with uniform composition throughout the process oftransport and placing.
o Test methods to determine workability of Self Compacting Concrete are:
1. Slump flow test
2. V Funnel Test
3. L Box Test
4. U Box Test
5. Fill Box Test
2. What is mean by permeability of concrete. Whatare the factors affecting
permeability of concrete?
o Rate at which water can penetrate concrete.
o Influence primarily by:
o Nature of hardened cement paste
o Porosity and W/c ratio
o Degree of compaction, Type and quantity of aggregates used
3. Explain the self-compacting concrete.
No vibration needed
Self compacted
Flow around obstructions
Encapsulate reinforcement and fill up the formwork completely under its own
weight.
Requirements of a SCC:
o FILLING ABILITY
o Ability of concrete to flow into and fill completely all spaces in the
formwork, under its own weight.
o PASSING ABILITY
o To flow through congested reinforcements
o SEGREGATIONRESISTANCE
o To remain in homogenous composition during transport and placing
4. List various specialconcreting cases.
o Underground and underwater concreting
o Concreting in cold weather
o Concreting in hot weather
o Mass concreting
o Concreting in marine environment
28. 5. Write short notes on underground and underwater concreting. What are the
precautions to be takenduring under waterconcreting?
o Placing concrete underground or underwater
o Special precautions should be selected
o Slump = 15 – 18 cm
o Methods:
o Tremie method
o Bucket placing
o Placing in bags
o Pre-packed concrete and Placing in dewatered caissons
o Requirements:
o Workability and self compaction
o Cohesion about washout and segregation
o Low heat of hydration
o Controlled set time
o Compressive strength and adequate bond strength
1. Tremie Method:
o Tremie is a water tight pipe – 250 mm dia
o One end of formwork(or pipe) below water and other end above water
o Funnel shape at top and loose plug at bottom
o Supported on a working platform above water level.
o Concrete is poured from top to bottom through this pipe with help of gravity
o Before concreting air and water must be excluded
2. BucketPlacing:
o Large quantity of STIFF/HARD concrete filled in bucket
o Bucket is lowered to required depth using crane
o Top of bucket is suitably covered to avoid disturbances
o The bucket is opened by divers or suitable arrangement from the top
o Early discharge of concreteshould be prevented, so as to avoid entry of water
into it.
29. o Only used for shallow depths.
3. Placing in bags:
o Concrete is filled in gunny/cotton bags
o Lowered into water and placed carefully in a header and stretcher fashion by
divers.
o Slow and laborious
o Accurate placing is difficult
o Expensive
o For shallow waters only
6. What are the factors affecting properties of fibre reinforced concrete?
o Inclusion of fibers
o Closely spaced
o Uniformly dispersed
o Composite material
o Resistance to crack growth
o Improve tensile strength
o Improve durability
7. Write a note Polymer concrete
o Concrete containing polymers
Why Polymer concrete?
o Different drawbacks of concrete are eliminated
o Reducing the drawbacks of ordinary concrete
o Alternative to conventional concrete
o Reduce green house effect
o Reduce energy consumption
30. Uses:
o Precast works
o Floor and pavements
o Channel sections
8. What are different types of polymer concrete?
Polymer Impregnated Concrete (PIC):
Impregnating a hardened Portland cement concrete with a monomer
Polymerize the monomer in site.
Improves durability
Improves surface resistance
Monomer used for impregnation are
o Methyl Methacrylate
o Styrene
o T-Butyl styrene
o Epoxy
Polymer Portland Cement Concrete (PPCC)
Replacing a part of mixing water with LATEX
Latex means polymer emulsion
9. Write a note on geo-polymerconcrete?
Made from flyash and alkaline solution
Combines waste products to useful product
Setting mechanism depends on polmerisation
Curing temperature is b/w 600-900 C
Reduce CO2 emissions Less green house gas
High fire resistance
High compressive strength
Rapid strength gain
31. Less shrinkage
Greater corrosionresistance
10.Write a note on no fines concrete and its applications
Fine aggregate fraction is omitted
CA + Cement + Water only.
Light in weight
Offers architecturally attractive look
Bond strength is low- reinforcement - X
Formworks can be removed earlier – less side thrust
Low drying shrinkage
Low thermal conductivity
Applications:
o Load bearing walls
o For temporary structures
o Heat insulation
o Good basefor plastering
o Dampness free walls
o Where sand is not available, no-fines concrete becomea popular
construction material
11.List the defects in concrete.
o Cracks
Excess water – evaporation /freezing – volume changes
Alkali aggregate reaction
Corrosionof steel bars
Freezing and thawing
o Crazing
o Sulphate deterioration
o Effloresence
Appearance if fluffy white patches on surface of concrete
o Segregation
o Bleeding
o Laitance
Cement and water slurry coming out to top of concrete surface
12.How defects canbe reduced?
Defects can be reduced by:
1. Selection of cement as desired quality by IS
2. Selection of aggregates of desired quality as per IS
3. Maintaining accurate water cement ratio
4. Properbatching of ingredients
5. Properoperation in productionof concrete
6. Carefulness in finishing items
32. 13.What is mean by pre-packedconcrete?
o Also called as GROUNTED CONCRETE
o Special technique of placing concrete under water
o Used where reinforcement is complicated – mass concreting, piers, Pipes,
conduits, openings, etc
o Place coarseaggregate only in the form and thoroughly compacting it to form a
prepacked concrete
o This prepacked mass is grouted with cement mortar of required proportions.
o Undergoes less drying shrinkage
14.What is mean by guniting or shotcreting?
o Gunite – mortar conveyed through a hose and pumped with a high velocity to
the surface
o Forceof the jet impacting on the surface compactthe material
o Eg: Rediset cement
o Process –
o Dry mix process
o Wet mix process
15.Write a note on concreting in coldweather?
o Small cracks water enters become ice
volume increases concrete cracks
o Temperature to be maintained = 50C
o Effects
Delayed setting
Freezing of concrete at early age
Freezing and thawing
Temperature stresses
o Recommended practices and precautions
Selection of suitable type of cement
Temperature control of ingredients
Electrical heating of concrete mass
Use of insulating formwork
Admixtures of anti-freezing materials
Use of air entraining agents
Delayed removal of form work
Placing and curing of concrete
Study this with code book- Module III – Mix design.
IS 456:2000 andIS 10262:2009permitted in exam hall
33. 1. Design a concretemix w.r.t following data.
Grade of concrete : 30 MPa
Type of cement : OPC 43 Grade
Maximum nominal size of coarse aggregate Fraction I = 20 mm
Fraction II = 10 mm
Maximum water cement ratio : 0.45
Maximum cement content : 360 mm
Specific gravity of cement : 3.15
Specific gravity of sand : 3.15
Specific gravity of C.A : 3.15
o Assume all other data suitably.
<<Refer Notebook for details>>
_______
Shamjith KM
HOD, Civil Engineering
OPTC Edavanna