1. The pullout test measures the force required to pull an embedded metal insert from hardened concrete. It was first described in 1938 and research in the 1960s aimed to optimize the geometry and develop simple field equipment with high correlation to compressive strength.
2. An embedment depth of 50mm was chosen as it tests beyond the surface while not requiring too much force. Tests established the optimal insert head and bearing ring diameters. Failure involves cracking around the insert and aggregate interlock up to the ultimate load.
3. For field use, a 25mm diameter steel disc on a conical stem is embedded and pulled against a reaction ring using a hydraulic jack, measuring the force. The test estimates concrete strength to determine
The document provides instructions for conducting pull-out tests to determine the compressive strength of concrete. It states that pull-out tests should be confirmed to BS 1881 Part 207 and give a direct tensile strength value. It describes how inserts can be cast into wet concrete or positioned in hardened concrete using an under-reamed groove. When testing, at least four pull-out tests should be performed at each location and a loading rate of 0.5 ± 0.2 kN/s should be used for 25mm diameter inserts. The compressive strength can then be calculated from the direct tensile strength value obtained during testing.
This document provides instructions for conducting a pull off test to determine the tensile strength of concrete. The test shall follow British Standard 1881 Part 207 and involves partially coring into the concrete and bonding a metal block to pull off from the surface using a hydraulic jack. Reinforcing steel should be avoided within the coring area or at a depth equal to the maximum aggregate size to obtain valid results. Six tests are typically needed at each test location.
Self-compacting concrete (SCC) was developed in Japan in the 1980s to achieve complete compaction without vibration. SCC flows under its own weight, fills formwork and passes through reinforced areas without segregation of ingredients. It consists of cement, fine and coarse aggregates, chemical and mineral admixtures. Superplasticizers and viscosity modifying agents provide workability and stability. Tests like slump flow, V-funnel, and J-ring evaluate filling ability, passing ability and resistance to segregation. SCC offers benefits of reduced labor, better compaction and surface finish compared to conventional concrete but requires more precise material proportions and quality control.
Cement is tested through laboratory and field tests to evaluate its properties and suitability. Key laboratory tests described in the document include:
- Fineness tests which measure particle size and surface area to determine reactivity.
- Setting time tests which ensure cement sets within specified time limits.
- Compressive strength tests where cement mortar cubes are crushed to determine strength over time.
- Soundness and loss of ignition tests which evaluate volume stability and carbon/moisture content.
Results of laboratory tests help ensure cement meets standards before use in construction projects.
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.
The document discusses factors that affect the strength of concrete, including water-cement ratio, aggregate-cement ratio, maximum aggregate size, and degree of compaction. It states that concrete strength is inversely proportional to water-cement ratio according to Abrams' law. A lower water-cement ratio and higher degree of compaction produce stronger concrete by reducing porosity. A leaner aggregate-cement ratio also increases strength by absorbing water and reducing shrinkage. Larger aggregate size can reduce water needs but may decrease strength by lowering surface area for bond development.
The document provides instructions for conducting pull-out tests to determine the compressive strength of concrete. It states that pull-out tests should be confirmed to BS 1881 Part 207 and give a direct tensile strength value. It describes how inserts can be cast into wet concrete or positioned in hardened concrete using an under-reamed groove. When testing, at least four pull-out tests should be performed at each location and a loading rate of 0.5 ± 0.2 kN/s should be used for 25mm diameter inserts. The compressive strength can then be calculated from the direct tensile strength value obtained during testing.
This document provides instructions for conducting a pull off test to determine the tensile strength of concrete. The test shall follow British Standard 1881 Part 207 and involves partially coring into the concrete and bonding a metal block to pull off from the surface using a hydraulic jack. Reinforcing steel should be avoided within the coring area or at a depth equal to the maximum aggregate size to obtain valid results. Six tests are typically needed at each test location.
Self-compacting concrete (SCC) was developed in Japan in the 1980s to achieve complete compaction without vibration. SCC flows under its own weight, fills formwork and passes through reinforced areas without segregation of ingredients. It consists of cement, fine and coarse aggregates, chemical and mineral admixtures. Superplasticizers and viscosity modifying agents provide workability and stability. Tests like slump flow, V-funnel, and J-ring evaluate filling ability, passing ability and resistance to segregation. SCC offers benefits of reduced labor, better compaction and surface finish compared to conventional concrete but requires more precise material proportions and quality control.
Cement is tested through laboratory and field tests to evaluate its properties and suitability. Key laboratory tests described in the document include:
- Fineness tests which measure particle size and surface area to determine reactivity.
- Setting time tests which ensure cement sets within specified time limits.
- Compressive strength tests where cement mortar cubes are crushed to determine strength over time.
- Soundness and loss of ignition tests which evaluate volume stability and carbon/moisture content.
Results of laboratory tests help ensure cement meets standards before use in construction projects.
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.
The document discusses factors that affect the strength of concrete, including water-cement ratio, aggregate-cement ratio, maximum aggregate size, and degree of compaction. It states that concrete strength is inversely proportional to water-cement ratio according to Abrams' law. A lower water-cement ratio and higher degree of compaction produce stronger concrete by reducing porosity. A leaner aggregate-cement ratio also increases strength by absorbing water and reducing shrinkage. Larger aggregate size can reduce water needs but may decrease strength by lowering surface area for bond development.
The document describes 7 different tests conducted on cement:
1. Field testing examines the cement's appearance, texture, and behavior when mixed with water.
2. The standard consistency test determines the percentage of water needed to achieve a standardized consistency for cement paste.
3. The fineness test evaluates the particle size distribution of cement, with finer particles offering a greater surface area for hydration.
4. The soundness test ensures cement does not expand after setting, which could indicate excess lime causing unsoundness.
5. The strength test measures the compressive strength of cement mortar mixtures at various ages (3, 7, 28 days).
6. The heat of hydration test examines the heat released
1. The document discusses various destructive and non-destructive testing methods for measuring the properties of hardened concrete. 2. Destructive tests include cube tests to determine compressive strength and split-cylinder or flexural tests to determine tensile strength. 3. Non-destructive tests discussed are rebound hammer testing, ultrasonic pulse velocity testing, penetration resistance testing, pull-out testing, and using a profometer.
Underwater concrete (UWC) requires special mix designs, placement techniques, and quality control due to the challenges of placing concrete underwater. The document discusses types of materials used in UWC including cement, aggregates, and admixtures. It also describes common placement methods like the tremie method, pump method, and bagwork. Construction techniques for placing UWC include the use of caissons and cofferdams to create a dry work environment. Proper production, quality control measures, and maintenance are needed to ensure the durability of underwater concrete structures.
Admixtures are added in concrete to improve the quality of concrete.
Fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBS), Metakaolin (MK), and rice husk ash (RHA)
Possess certain characteristics through which they influence the properties of concrete differently.
Effect of mineral admixtures on the properties of fresh concrete is very important as these properties may affect the durability and mechanical properties of 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.
The document discusses the fresh and hardened properties of concrete. It describes workability, segregation, and bleeding as important fresh properties. Workability is affected by water content, mix proportions, aggregate size and shape. The slump cone test and compaction factor test are described for measuring workability. Hardened properties discussed include compressive strength, flexural strength, and modulus of elasticity. The compression test, flexural strength test, and stress-strain relationship determination are described for evaluating hardened properties.
DESTRUCTIVE AND NON-DESTRUCTIVE TEST OF CONCRETEKaran Patel
The standard method of evaluating the quality of concrete in buildings or structures is to test specimens cast simultaneously for compressive, flexural and tensile strengths.
The main disadvantages are that results are not obtained immediately; that concrete in specimens may differ from that in the actual structure as a result of different curing and compaction conditions; and that strength properties of a concrete specimen depend on its size and shape.
Although there can be no direct measurement of the strength properties of structural concrete for the simple reason that strength determination involves destructive stresses, several non- destructive methods of assessment have been developed.
This document provides information on aggregates used in traditional building materials. It defines aggregates as fillers used with binding materials that are derived from rocks. Aggregates make up 70-80% of concrete's volume and influence its properties. Aggregates are broadly classified into fine aggregates smaller than 4.75mm and coarse aggregates larger than 4.75mm. The document discusses various types of coarse aggregates based on geological origin, size, shape, and unit weight. It also covers properties of aggregates like strength, shape, specific gravity, moisture content and tests conducted on aggregates. Alkali aggregate reaction and measures to prevent it are summarized.
This document discusses high-strength concrete (HSC). It defines HSC as concrete with a 28-day compressive strength of over 40 MPa. HSC uses a low water-cement ratio, smaller aggregate sizes, and admixtures like silica fume and superplasticizers. Compared to normal-strength concrete, HSC has higher resistance to pressure, modulus of elasticity, and strength gained at an earlier age. Some applications of HSC mentioned include bridges, high-rise buildings, power plants, and skyscrapers. The document concludes that interest in HSC is growing rapidly due to its advantages like reduced material needs and increased construction speeds.
This document provides information on concrete, including:
- Concrete is a mixture of cement, water, and aggregates that hardens over time into a strong building material.
- Proper mixing, placing, and curing of the concrete allows it to gain strength through a process called hydration as it ages.
- Factors like the water-cement ratio, type of aggregates, compaction, and curing affect the properties and strength of hardened concrete.
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 metakaolin, which is produced by calcining kaolin clay between 650-800°C. It has pozzolanic properties and can partially replace cement in high strength concrete. Metakaolin increases the strength and durability of concrete by reacting with calcium hydroxide to produce additional calcium-silicate-hydrate gel. It improves the physical and chemical properties of concrete, leading to applications in infrastructure like bridges, dams, and buildings where high strength and durability are important.
The document discusses the rebound hammer test, which is a non-destructive testing method used to determine the compressive strength of concrete. The rebound hammer test works by striking an elastic mass against the concrete surface and measuring the rebound; a higher rebound number indicates higher compressive strength. Several factors can influence the test results, including the type of aggregate, cement, surface condition, curing and age of the concrete. To obtain accurate readings, the test procedure and data interpretation must account for these potential variables.
The document discusses various tests used to evaluate the properties of fresh and hardened concrete, including slump tests, compaction factor tests, Vee-Bee consistometer tests, flow tests, and Kelly ball tests for fresh concrete workability. Hardened concrete is evaluated using rebound hammer tests to estimate compressive strength and ultrasonic pulse velocity tests to assess quality. A case study describes a reinforced concrete structure collapse due to design flaws in accounting for beam-column joint forces, inadequate reinforcement detailing, and omitted column links.
This document discusses quality control of concrete through various tests on fresh and hardened concrete. It begins with an introduction to concrete and quality, then discusses where quality control begins in the production of materials and continues through handling, batching, mixing, transporting and placing concrete. Key tests on fresh concrete include slump and compacting factor tests, while tests on hardened concrete include compression, tensile strength, and flexural strength tests to evaluate the quality and strength of the concrete. The document also reviews materials used in concrete such as cement, water, aggregates, and admixtures.
you would be aware about the different types of special concrete being used in india.All these types of concrete are being produced by ultratech concrete, for more details visit www.ultratechconcrete.com/concrete_types.html
Pullout test as a nondestructive test method in structural engineering Ahmed Abdullah
- The pullout test measures the force required to pull an embedded metal insert from hardened concrete. It has been shown to have good correlation with compressive strength.
- The failure mechanism involves initial cracking around the insert followed by the development of microcracks between the insert and bearing ring. Beyond ultimate load, a circumferential crack forms extracting the failure cone.
- Within-test variability, or repeatability, of pullout tests on the same concrete is typically a coefficient of variation of 4-15%, with an average of 8%. The size of coarse aggregate affects variability.
Laboratory experimental study and elastic wave velocity on physical propertie...HoangTienTrung1
Pressure grouting has gained popularity as a soil reinforcement method. However, the behavior of the interface between rock and grout is not well known. This study investigates the interaction of pressure grouting and rock, through a series of laboratory tests performed on specially designed and fabricated equipment and using standard testing methods. The test measures the density, compressional strength, and frictional resistance of grout relative to the applied pressure and curing time. Simultaneously, the velocities of the elastic wave traveling through the grout are obtained to develop correlations between the physical properties of the grout and the test conditions. The results of the tests show that the density, compressional strength, and frictional resistance of the grout increase with applied pressure and curing time. The strengths of the influencing factors are seen to be correlated within the range of the test conditions. Using the results of these tests, the potential development of a new method that requires less cement was discussed.
The document describes 7 different tests conducted on cement:
1. Field testing examines the cement's appearance, texture, and behavior when mixed with water.
2. The standard consistency test determines the percentage of water needed to achieve a standardized consistency for cement paste.
3. The fineness test evaluates the particle size distribution of cement, with finer particles offering a greater surface area for hydration.
4. The soundness test ensures cement does not expand after setting, which could indicate excess lime causing unsoundness.
5. The strength test measures the compressive strength of cement mortar mixtures at various ages (3, 7, 28 days).
6. The heat of hydration test examines the heat released
1. The document discusses various destructive and non-destructive testing methods for measuring the properties of hardened concrete. 2. Destructive tests include cube tests to determine compressive strength and split-cylinder or flexural tests to determine tensile strength. 3. Non-destructive tests discussed are rebound hammer testing, ultrasonic pulse velocity testing, penetration resistance testing, pull-out testing, and using a profometer.
Underwater concrete (UWC) requires special mix designs, placement techniques, and quality control due to the challenges of placing concrete underwater. The document discusses types of materials used in UWC including cement, aggregates, and admixtures. It also describes common placement methods like the tremie method, pump method, and bagwork. Construction techniques for placing UWC include the use of caissons and cofferdams to create a dry work environment. Proper production, quality control measures, and maintenance are needed to ensure the durability of underwater concrete structures.
Admixtures are added in concrete to improve the quality of concrete.
Fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBS), Metakaolin (MK), and rice husk ash (RHA)
Possess certain characteristics through which they influence the properties of concrete differently.
Effect of mineral admixtures on the properties of fresh concrete is very important as these properties may affect the durability and mechanical properties of 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.
The document discusses the fresh and hardened properties of concrete. It describes workability, segregation, and bleeding as important fresh properties. Workability is affected by water content, mix proportions, aggregate size and shape. The slump cone test and compaction factor test are described for measuring workability. Hardened properties discussed include compressive strength, flexural strength, and modulus of elasticity. The compression test, flexural strength test, and stress-strain relationship determination are described for evaluating hardened properties.
DESTRUCTIVE AND NON-DESTRUCTIVE TEST OF CONCRETEKaran Patel
The standard method of evaluating the quality of concrete in buildings or structures is to test specimens cast simultaneously for compressive, flexural and tensile strengths.
The main disadvantages are that results are not obtained immediately; that concrete in specimens may differ from that in the actual structure as a result of different curing and compaction conditions; and that strength properties of a concrete specimen depend on its size and shape.
Although there can be no direct measurement of the strength properties of structural concrete for the simple reason that strength determination involves destructive stresses, several non- destructive methods of assessment have been developed.
This document provides information on aggregates used in traditional building materials. It defines aggregates as fillers used with binding materials that are derived from rocks. Aggregates make up 70-80% of concrete's volume and influence its properties. Aggregates are broadly classified into fine aggregates smaller than 4.75mm and coarse aggregates larger than 4.75mm. The document discusses various types of coarse aggregates based on geological origin, size, shape, and unit weight. It also covers properties of aggregates like strength, shape, specific gravity, moisture content and tests conducted on aggregates. Alkali aggregate reaction and measures to prevent it are summarized.
This document discusses high-strength concrete (HSC). It defines HSC as concrete with a 28-day compressive strength of over 40 MPa. HSC uses a low water-cement ratio, smaller aggregate sizes, and admixtures like silica fume and superplasticizers. Compared to normal-strength concrete, HSC has higher resistance to pressure, modulus of elasticity, and strength gained at an earlier age. Some applications of HSC mentioned include bridges, high-rise buildings, power plants, and skyscrapers. The document concludes that interest in HSC is growing rapidly due to its advantages like reduced material needs and increased construction speeds.
This document provides information on concrete, including:
- Concrete is a mixture of cement, water, and aggregates that hardens over time into a strong building material.
- Proper mixing, placing, and curing of the concrete allows it to gain strength through a process called hydration as it ages.
- Factors like the water-cement ratio, type of aggregates, compaction, and curing affect the properties and strength of hardened concrete.
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 metakaolin, which is produced by calcining kaolin clay between 650-800°C. It has pozzolanic properties and can partially replace cement in high strength concrete. Metakaolin increases the strength and durability of concrete by reacting with calcium hydroxide to produce additional calcium-silicate-hydrate gel. It improves the physical and chemical properties of concrete, leading to applications in infrastructure like bridges, dams, and buildings where high strength and durability are important.
The document discusses the rebound hammer test, which is a non-destructive testing method used to determine the compressive strength of concrete. The rebound hammer test works by striking an elastic mass against the concrete surface and measuring the rebound; a higher rebound number indicates higher compressive strength. Several factors can influence the test results, including the type of aggregate, cement, surface condition, curing and age of the concrete. To obtain accurate readings, the test procedure and data interpretation must account for these potential variables.
The document discusses various tests used to evaluate the properties of fresh and hardened concrete, including slump tests, compaction factor tests, Vee-Bee consistometer tests, flow tests, and Kelly ball tests for fresh concrete workability. Hardened concrete is evaluated using rebound hammer tests to estimate compressive strength and ultrasonic pulse velocity tests to assess quality. A case study describes a reinforced concrete structure collapse due to design flaws in accounting for beam-column joint forces, inadequate reinforcement detailing, and omitted column links.
This document discusses quality control of concrete through various tests on fresh and hardened concrete. It begins with an introduction to concrete and quality, then discusses where quality control begins in the production of materials and continues through handling, batching, mixing, transporting and placing concrete. Key tests on fresh concrete include slump and compacting factor tests, while tests on hardened concrete include compression, tensile strength, and flexural strength tests to evaluate the quality and strength of the concrete. The document also reviews materials used in concrete such as cement, water, aggregates, and admixtures.
you would be aware about the different types of special concrete being used in india.All these types of concrete are being produced by ultratech concrete, for more details visit www.ultratechconcrete.com/concrete_types.html
Pullout test as a nondestructive test method in structural engineering Ahmed Abdullah
- The pullout test measures the force required to pull an embedded metal insert from hardened concrete. It has been shown to have good correlation with compressive strength.
- The failure mechanism involves initial cracking around the insert followed by the development of microcracks between the insert and bearing ring. Beyond ultimate load, a circumferential crack forms extracting the failure cone.
- Within-test variability, or repeatability, of pullout tests on the same concrete is typically a coefficient of variation of 4-15%, with an average of 8%. The size of coarse aggregate affects variability.
Laboratory experimental study and elastic wave velocity on physical propertie...HoangTienTrung1
Pressure grouting has gained popularity as a soil reinforcement method. However, the behavior of the interface between rock and grout is not well known. This study investigates the interaction of pressure grouting and rock, through a series of laboratory tests performed on specially designed and fabricated equipment and using standard testing methods. The test measures the density, compressional strength, and frictional resistance of grout relative to the applied pressure and curing time. Simultaneously, the velocities of the elastic wave traveling through the grout are obtained to develop correlations between the physical properties of the grout and the test conditions. The results of the tests show that the density, compressional strength, and frictional resistance of the grout increase with applied pressure and curing time. The strengths of the influencing factors are seen to be correlated within the range of the test conditions. Using the results of these tests, the potential development of a new method that requires less cement was discussed.
1) The document reports on a laboratory experiment to test the compressive and tensile strengths of concrete. Cubes and cylinders were cured for 14 days and then tested.
2) The compressive strength of the cubes was found to be 19.11 N/mm2 on average, while the cylinders was 14.71 N/mm2. The ratio of 0.8 between cylinder and cube strengths was as expected.
3) The tensile strength was found to be 2.05 N/mm2, which is approximately 10% of the compressive strength of the cubes, showing that concrete is weaker in tension.
Evaluation of concrete spall repairs by pullout testfrank collins
This document summarizes a study that evaluated concrete spall repairs using pullout tests. Concrete specimens were damaged via an initial pullout test, repaired with epoxy mortar, and subjected to a second pullout test. The tests showed that:
1) Pullout force of repaired specimens was linearly correlated with concrete cylinder compressive strength up to around 45 kN/2.26 MPa, but diminished at higher strengths.
2) Pullout force/stress of repaired specimens increased similarly to concrete specimens as age increased up to 90 days, but was lower than unrepaired concrete.
3) Higher initial pullout damage forces resulted in higher pullout forces for repaired specimens, up to around 43
Nondestructive material testing with ultrasonicsFatma Abdalla
Ultrasonic pulse velocity (UPV) testing is a non-destructive testing method used to evaluate the quality and strength of concrete structures. UPV works by measuring the speed that ultrasonic pulses travel through the concrete, with higher velocities indicating higher quality concrete of greater density, homogeneity, and strength. The document describes experiments conducted to determine the relationship between UPV test results and compressive concrete strength for samples with varying water-cement ratios. UPV and compressive strength tests were performed on concrete samples at different ages. The results showed that UPV and strength increase with age and samples with lower water-cement ratios have higher UPV and strength. Correlation curves were developed to allow predicting concrete strength from
A fracture mechanics based method for prediction ofSAJITH GEORGE
The document presents a fracture mechanics-based method for predicting cracking in circular and elliptical concrete rings undergoing restrained shrinkage. It describes an experimental program using different ring geometries and material tests to determine properties. A numerical model is developed using ANSYS to model the restrained shrinkage process and calculate stress intensity factors. The model uses a fictitious temperature field to simulate shrinkage and determines cracking age by comparing driving and resistance curves. It finds cracking occurs earlier in elliptical rings and the method accurately predicts experimental cracking ages.
Non-destructive testing methods can provide information about the properties of existing concrete structures without damaging them. Various methods are described in the document, including rebound hammer testing, ultrasonic pulse velocity testing, and radioactive methods. These methods measure physical properties like hardness, ultrasonic pulse transmission, and density that can help indicate characteristics like strength and uniformity or detect issues like cracking and honeycombing. Interpretation requires calibration and accounting for factors like materials and curing conditions. The goal of non-destructive testing is to evaluate concrete quality, strength, integrity, reinforcement, and signs of deterioration.
This document examines deflection criteria for masonry beams and lintels. It discusses previous research that showed masonry walls and beams act compositely, with the masonry in compression and beam in tension. Deflection limits of l/600 are suggested to prevent serviceability issues during construction. Methods for determining deflection of reinforced masonry beams are examined, with recommending using an effective moment of inertia approach. A span limit of l/d=8 is proposed where deflections do not need to be checked.
1) Several non-destructive testing methods have been developed to evaluate the quality and strength of concrete without damaging it, including penetration tests, rebound tests, pull-out techniques, dynamic tests, and radioactive tests.
2) Penetration tests measure the depth that a probe penetrates the concrete, rebound tests measure the rebound distance of a hammer striking the concrete, and pull-out tests measure the force required to remove a steel rod cast into the concrete.
3) Dynamic tests like ultrasonic pulse velocity tests measure the speed of ultrasonic pulses through the concrete, which can indicate quality and strength. Radioactive tests use gamma rays to detect reinforcement location and density variations.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
VTU CBCS SCHEME Concrete Technology. Tests on Harden ConcreteSachin dyavappanavar
1) The document discusses various destructive and non-destructive tests used to evaluate the properties of hardened concrete, including compressive strength, tensile strength, flexural strength, rebound hammer, and ultrasonic pulse velocity tests.
2) Compressive strength, tensile strength, and flexural strength tests are conducted by applying loads to concrete specimens to failure.
3) Non-destructive tests like rebound hammer and ultrasonic pulse velocity provide indications of concrete strength without damaging specimens.
The document describes an extension to the brittle cracking concrete material model in ABAQUS. The extension adds nonlinear compressive behavior using a user subroutine. The extended model is validated by comparing it to the original brittle cracking model and damaged plasticity model under uniaxial loading. The extended model is also shown to capture strain rate effects observed in experiments. Finally, the extended model is used to simulate benchmark cases including a notched concrete beam, demonstrating its ability to model tensile failure of concrete structures.
1) The study investigates the effect of reservoir hydrostatic pressure on the seismic response of roller compacted concrete (RCC) dams using finite element analysis.
2) Analysis of the Kinta RCC dam in Malaysia shows that hydrostatic pressure increases stresses by 25% and changes displacement response from negative to positive direction. It also causes more damage at the heel of the dam.
3) Consideration of hydrostatic pressure leads to a 13% increase in maximum horizontal deformation, from 76.5 mm to 86.6 mm, and changes the zone of peak deformation from the base to the crest of the dam. It also changes the displacement response of nodes from negative to positive.
The Crack Pattern Of R.C Beams Under LoadingAhmed Abdullah
1. A reinforced concrete beam was tested under static two-point concentrated loading to study the effect of different web reinforcement arrangements on ultimate shear strength.
2. It was observed that diagonal cracks developed first in deeper beams while flexural cracks developed first in shallower beams with sufficient reinforcement.
3. The crack pattern and failure mode were similar across all test beams despite variations in web reinforcement, with diagonal cracks forming first in deeper beams.
This document presents a simplified method for estimating the entire load profile of a fully grouted anchor bolt based on strain measurement data from two points near the loaded end. Pullout tests were conducted on anchor bolts grouted in concrete with two different grout types. Strain gauges attached to the bolts recorded data during loading. Interpolation of data from two gauges was able to estimate the full load profile along the bolt, matching the profile obtained from multiple gauges. This method provides a simplified way to determine an anchor bolt's load profile without needing data from along its entire length.
This paper involves an experimental investigation on the flexural behaviour of curved beams and comparison of its results with conventional beams. Curved beams of size 1200 x 150 x 100 mm with varying initial curvature as 4000mm, 2000mm and the concrete strength as M40 is considered. Various reinforcement are provided in the curved beams to predict which reinforcement detail would give more resistant over maximum loading. The material properties of cement, fine aggregate, coarse aggregate and the compressive strength of concrete cube were found out. A total of 12 specimens of curved beams were casted with various combination of reinforcement along with three control specimens. The beams are tested under two point loading both horizontally and vertically. The deflection and maximum moment carrying capacity are investigated to understand its strength. Also analytical modelling is done to determine the ultimate moment carrying capacity using Finite Element Software ABAQUS to compare with the experimental model.
This document presents a new approach for determining the tensile and shear strengths of normal weight concrete. It discusses existing methods for evaluating these properties and their limitations. The author proposes using the failure patterns of two concrete cylinders under compression - with the same cross-sectional area but different heights - to define a characteristic fracture angle. This angle would be a function of the concrete's compressive strength. Equations are then developed relating the fracture angle to the tensile and shear strengths. The significance of using two cylinders is that it introduces the concept of the direction of the failure plane as a way to predict mechanical properties from a standard compression test.
International Journal of Engineering Research and DevelopmentIJERD Editor
1) The study investigated the effect of aggregate size on the energy dissipation of plain concrete members subjected to static cyclic loading.
2) Testing found that smaller aggregate size (3/8") resulted in less energy dissipation compared to larger sizes (1/2", 3/4"), and gradually increasing loads led to less energy dissipation than constant loads.
3) Measurement of crack propagation using ultrasound found that larger aggregate sizes led to larger cracks under both constant and gradually increasing loads.
This document summarizes a civil engineering student project evaluating factors and remedies for bonding between old and new concrete layers. Tests will include slant shear tests and flexural tests to assess bond strength. Molds have been cast and will be tested in 3-4 days. The project will evaluate the effects of surface roughness, epoxy application, and wire mesh on bond strength and the overall strength of an overlay system compared to a monolithic structure.
This document summarizes a civil engineering student project evaluating factors and remedies for bonding between old and new concrete layers. Students will conduct slant shear and flexural tests on molds with different surface treatments and bonding materials. The tests will assess bond strength. Surface roughness, epoxy, and wire mesh will be evaluated as potential remedies to strengthen bonding. Test results will show the effect of concrete overlays on the overall strength of members compared to monolithic members.
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Pullout test as nondestructive test method in structural engineering
1. 1
Gaziantep University
College of Engineering
Civil Engineering Department
Report On
Pullout test As Nondestructive test
method in Structural Engineering
Submitted by
Mohammed Layth Abbas
Student No:201444956
Supervisor
Assoc.Prof. Esra Mete Güneyisi
CE 550
(Nondestructive Testing and Evaluation in Structural Eng)
2. 2
BACKGROUND
The pullout test measures the force required to pull an embedded metal insert from
hardened concrete. The earliest known description of the pullout test method was
reported in 1938 by Skramtajeu of the Central Institute for Omdistroa in the Soviet
Union. Figures 1 and 2 show the schematics for some of the first pullout equipment.
In 1962, Kierkegaard-Hansen initiated a research program to determine the optimum
geometry for the pullout test. The objectives of this research program were to develop
simple equipment that could be used in the field and also have a high correlation
between the ultimate pullout force and the compressive strength. According to
Kierkegaard-Hansen, the embedment depth should be sufficient to assure that more
than the outer-most surface of the concrete is tested and some coarse aggregate is
included within the failure cone. This suggests that a deeper embedment is better.
However, with increasing depth, the force required to pull out the insert also
increases, which would require bulkier equipment and a larger failure area. Based on
these factors, an embedment depth of 50 mm (1 in) was chosen arbitrarily.
Kierkegaard-Hansen also performed a number of tests in an effort to establish the
optimum diameter to be used for the insert head and the bearing ring. Because a
suitable tension loading system did not exist, a lab compression machine was used to
apply the load. The insert was tested by applying a compressive load to the bottom of
the embedded disk. Figure 3 graphically shows that the test can also be considered as
a punching-type test. The Danish word for punching is "lokning." Therefore, the
quantity measured by the test was called "lok-strength" rather than the pullout
strength. This is why the pullout test is sometimes referred to as the "LOK" test.
3. 3
As a result of this research, the correlation between pullout strength and compressive
strength was found to be nonlinear. In 1962, Kierkegaard-Hansen improved on the
initial research by introducing a bearing ring. This modification resulted in a failure
cone with a well-defined geometry that resulted in linear correlation between pullout
strength and compressive strength
TEST EQUIPMENT AND PROCEDURE
Figure 4 shows a schematic of the pullout insert. A force is applied to the insert by a
loading ram that is seated on a bearing ring and is concentric with the insert shaft. The
bearing ring transmits the reaction force to the concrete. As the insert is pulled out, a
conical-shaped fragment of concrete is extracted from the concrete.
In the pullout test, a 25 mm (l inch) diameter steel disc on a conical shaped stem is
embedded at least 25 mm (1 inch) below the surface of the concrete during casting. A
pull bolt is screwed into the stem of the disk and pulled by hydraulic force against a
surface mounted reaction ring. The disk is loaded to failure by means of a hand
operated portable hydraulic jack and the total force is measured on a gauge attached to
the jack.
4. 4
The pullout test can be used during construction to estimate the in-place strength of
concrete to help determine whether construction activities such as form removal,
application of post-tensioning, early opening to traffic, or termination of cold weather
protection can proceed. Because compressive strength is usually required to evaluate
structural safety, the ultimate pullout force measured during the in-place test is
converted to an equivalent compressive strength by means of a previously established
correlation relationship.
LABORATORY CALIBRATION PROCEDURE
Development of the correlation relationship between pullout force and compressive
strength should be performed for each specific concrete mix to be used. To date, there
are no standard procedures to establish the correlation data. However, suggested
correlation procedures are provided below.
Various techniques have been used to acquire companion pullout strength and
compressive strength data. Kierkegaard-Hansen placed pullout inserts in the bottoms
of standard cylinder specimens. A pullout test was performed on the cylinder, and
then the same cylinder was capped and tested for compressive strength. As long as the
pullout test was stopped at the point of maximum load, a cone was not extracted, and
the cylinder could be tested in compression without a significant effect on the results.
However, for compressive strength above 40 MPa
(5800 psi), lower pullout strengths resulted for 150x300 mm (6xl2-in) cylinders
compared to companion slabs.
A recommended alternative method is to place inserts in slabs and cast companion
standard cylinders. At designated ages, replicate pullout tests are performed on the
slab and replicate cylinders are compression tested. A drawback to this approach is
to assure that the pullout tests and compression tests are performed at the same
maturity. Because of their different masses and shapes, the slab and cylinders are not
likely to experience the same temperature history during the critical early stages when
strength changes rapidly with age and is strongly dependent on temperature history.
Failure to account for possible maturity differences can lead to inaccurate correlation
relationships. Either maturity meters should be used to ensure companion testing at
equal maturities, or compression tests should be performed on cores drilled from the
slab. While the latter approach helps ensure equal maturities, it is time consuming.
Refer to Chapter 7 in this guide for information on the maturity concept.
For commercially available pullout systems, having embedment depths of 30 mm (1.2
in) or less and apex angles of 70° or less, the preferred approach is to place inserts on
the side faces of 200-mm (8 in) cubes and cast companion standard cylinders.
Because of similar surface-to-volume ratios, the early-age temperature histories of the
two types of specimens will be similar. The cubes and cylinders should be compacted
similarly, and the use of an internal vibrator or a vibrating table is recommended.
American Concrete Institute (ACI) Committee 228 recommends in its "In-Place
Methods for Determination of Strength of Concrete," ACI 228.1R-89, performing
eight replicate pullout tests and two cylinder compression tests at each test age. These
numbers of tests ensure that the average pullout strength and average compressive
5. 5
strength are determined with about the same degree of certainty. By placing four
inserts in each cube, this recommendation requires two cubes and two cylinders at
each age. The specimens should be moist-cured until the time of testing.
The number of pullout and compression tests chosen to establish the correlation
relationship should satisfy two needs: (1) the tests should span as wide a range of
strength as possible, and (2) there should be enough points to define the relationship
with a reasonable degree of accuracy. Based on field experience, Bickley suggested
that the range of compressive strength should be at least 20 MPa (3000 psi) but
preferably greater than this .ACI Committee 228 recommends performing companion
tests at a minimum of six evenly spaced strength levels. Generally, if test ages are
increased by a factor of two there will be about the same strength increase between
successive tests.<6)
For example, tests at ages of 1, 2, 4, 8, 16, and 32 days should
result in approximately evenly spaced test points. This assumes a constant
temperature during the curing period. If pullout tests will be used to estimate in-place
strengths at very low levels, the first test age should be reduced to 12 hours. This will
require special care in handling low-strength specimens. Thus the recommended
correlation testing program involves casting at least 12 cubes, with 4 inserts per cube
and 12 cylinder specimens. The inserts in two cubes and two cylinders are tested at
each test age so as to produce evenly spaced points when correlation data are plotted.
The average of the pullout strengths and compressive strengths are used in a least
squares fit analysis to develop the correlation relationship
FAILURE MECHANISM
The pullout test subjects the concrete to a static load. Therefore, it should be possible
to calculate the internal stresses in the concrete and predict the onset of cracking and
the ultimate pullout force. This is desirable so that the ultimate pullout force can be
related to the strength properties of concrete. Unfortunately, the stress distribution is
not easy to calculate because the stresses are altered by the presence of coarse
aggregate particles. There is not a consensus on the failure mechanism at the ultimate
load. One theory is that the ultimate load occurs as a result of compressive failure of
concrete along a line from the bottom of the bearing ring to the top face of the insert.
The other theory is that the ultimate failure is governed by aggregate interlock across
the secondary crack system, and the ultimate load is reached when a sufficient number
of aggregate particles have been pulled out of the matrix.
Based on review of various analytical and experimental investigations that had been
conducted, Krenchel and Bickley concluded that the failure mechanism of the pullout
test involves the following stages (see figure 5):
Stage 1 - At a load of about 30 to 40 percent of the ultimate, "tensile cracks"
originate at the corner of the insert head and propagate into the concrete for a
distance of 15 to 20 mm (0.6 to 0.8 in) forming an apex angle between 100 and
135° (see figure 5(a)). This cracking concentrates subsequent straining of the
concrete so that "all load is taken up in the truncated zone" between the insert
head and the bottom of the bearing ring.
6. 6
Stage 2 - A large number of stable micro-cracks develop in the truncated zone,
these cracks run from the top of the insert head to the bottom of the bearing
ring, forming an apex angle of about 84° (see figure 5(b)). This second-stage
cracking occurs as the load increases up to and just past the ultimate load. These
stable microcracks are analogous to the vertical microcracks observed during an
ordinary uniaxial compression test of a cylinder or prism.
Stage 3 - Beyond the ultimate load, a circumferential "tensile/shear" crack
develops that forms the final shape of the extracted cone (see figure 5(c)).
Despite the lack of agreement on the exact failure mechanism, it has been shown that
the pullout strength has good correlation with the compressive strength of concrete
and the test also has good repeatability.
WITHIN-TEST VARIABILITY
Within-test variability, also called "repeatability," refers to the scatter of results when
the test is repeated on identical concrete using the same test equipment, procedures,
and personnel. For a given concrete, the repeatability of a test affects the number of
tests required to establish, with a desired degree of certainty, the average value of the
property being measured by the test.
If pullout tests are repeated on the same concrete at the same maturity, the ultimate
pullout loads would be expected to be normally distributed about the average value
and the standard deviation would be the measure of repeatability. However, if
replicate tests were performed on the same concrete but at different maturities, so that
there would be different average pullout strengths, it has been generally agreed among
several investigators that the coefficient of variation is the better statistic for
quantifying the repeatability of the pullout test. Reported values of the coefficient of
variation, for different aggregates and test configurations, have ranged from about 4 to
15 percent with an average value of about 8 percent. The maximum size of the
aggregate in relation to the embedment depth appears to be a significant factor. Tests
7. 7
on concrete made with coarse aggregate having a maximum size less than the
embedment depth tend to have lower variability.
FIELD TESTS
To estimate in-place strength, pullout tests are performed on a particular part of the
structure and the correlation relationship is used to convert the test results to a
compressive strength values. To determine if sufficient strength has been attained, the
estimated compressive strength is compared with the required strength in the
specifications. However, to provide for a margin of safety, the pullout test results need
to be looked at statistically rather than simply comparing the average estimated in-
place strength with the required strength.
Number of Tests
ASTM C 900 requires a minimum of five pullout tests for every 115 m3
(150 yd3
) of
concrete, or in case of slabs or walls for every 465 m2
(5000 ft2
) of the surface area of
one face. However, a greater number of inserts is recommended for added reliability
and as a safety measure in the event testing is begun too soon or some of the tests
were considered invalid.
Some investigators have suggested that a minimum of ten pullout tests should be
performed for a given concrete placement. As a practical matter, Bickley advocated
the placement of 15 inserts per 100 m3
(130 yd3
). When the anticipated desired
strength level is reached, five inserts are randomly selected for testing. If the results
indicate less than the required strength, testing is discontinued and additional curing is
provided. At a later age, the remaining 10 inserts are tested. This technique provides
for a reserve in the event that testing is done too soon. It is recommended that the
maturity method be used to determine the appropriate time to perform the pullout
tests, therefore reducing the possibility of doing the pullout tests too soon.
TYPICAL APPLICATIONS
The pullout test has been adopted as a standard test method in many parts of the
world, including North America, and has been used successfully on numerous large
construction projects. Primary use of the system has been in either controlling
formwork removal and the time of post-tensioning, or determining the minimum
amount of curing needed in cold-weather concreting. The system has been used on
cooling towers, chimneys, multi-story building frames, pipelines, bridges, and other
forms of construction.
CAPO (CUT AND PULLOUT)
A disadvantage of the standard pullout test is that the locations of the inserts must be
planned in advance of concrete placement so that the inserts can be fastened to the
formwork or floated in from the surface. In an effort to extend the application of
pullout testing to existing structures, the CAPO technique has been developed. It
8. 8
should be noted however that the CAPO test method has not been approved as an
ASTM standard test method.
This technique involves drilling a 18 mm (0.7in) diameter hole into the concrete. A
special concrete router bit is then used to route a 25 mm (l in) diameter slot at a depth
of 25 mm (1 in). An expandable metal washer is placed in the hole and the ring is
expanded. Figure 6 shows a schematic of the equipment. The expanded washer is then
pulled out of the concrete using the same loading system as that used for an ordinary
pullout test. Attempts at using the CAPO test in the field have indicated that the test is
cumbersome and has high variability. This high variability is probably due to the need
for a flat concrete surface that is perpendicular to the drilled hole. If these conditions
are not achieved, the bearing ring will not seat properly and test results will be erratic.