Evaluation of the expansion attained to date by concrete affected by alkali–silica reaction. Part I: Experimental study

2004 ◽  
Vol 31 (5) ◽  
pp. 826-845 ◽  
Author(s):  
Nizar Smaoui ◽  
Marc-André Bérubé ◽  
Benoit Fournier ◽  
Benoit Bissonnette ◽  
Benoit Durand
Keyword(s):  
Structural Integrity ◽  
Test Method ◽  
Alkali Silica Reaction ◽  
Test Surface ◽  
Surface Cracking ◽  
Concrete Cylinders ◽  
Width Measurements ◽  
American Society ◽  
Concrete Prism Test ◽  
Crucial Parameter

The expansion to date of the concrete from a structure affected by alkali–silica reaction (ASR) is a crucial parameter in the evaluation of the structural integrity of the structure. Three methods have been used to evaluate this expansion: (i) the "stiffness damage test" (SDT), (ii) the "damage rating index" (DRI), and (iii) surface cracking. Concrete cylinders were made using several types of coarse and fine reactive aggregates and subjected to the Canadian Standards Association (CSA) concrete prism test CSA A23.2-14A (or American Society for Testing and Materials (ASTM) test method C1293), i.e., at 38 °C and >95% relative humidity (RH). At various expansion levels, the specimens were subjected to SDT and DRI tests. Very good relationships were obtained between the expansion due to ASR and the SDT. The correlation between the ASR expansion and the DRI was not as good but still of interest. Width measurements of surface cracks were also performed on a number of blocks made with different reactive aggregates and exposed in the laboratory at 38 °C and >95% RH. The expansion estimated from these measurements was much lower than that measured on the blocks.Key words: aggregates, alkali–silica reaction, concrete expansion, damage rating index, petrography, stiffness damage test, surface cracking.

Evaluation of the expansion attained to date by concrete affected by alkali–silica reaction. Part II: Application to nonreinforced concrete specimens exposed outside

2004 ◽  
Vol 31 (6) ◽  
pp. 997-1011 ◽  
Author(s):  
Nizar Smaoui ◽  
Benoit Fournier ◽  
Marc-André Bérubé ◽  
Benoit Bissonnette ◽  
Benoit Durand
Keyword(s):  
Relative Humidity ◽  
Alkali Silica Reaction ◽  
Test Surface ◽  
Good Relationship ◽  
Surface Cracking ◽  
Reactive Aggregate ◽  
Concrete Blocks ◽  
Relationship Coefficient ◽  
Concrete Elements ◽  
Made In

In part I, relationships were obtained in the laboratory between the expansion due to alkali-silica reaction (ASR) and (i) the "stiffness damage test" (SDT), (ii) the "damage rating index" (DRI), and (iii) the surface cracking of the concrete. These tests were conducted on nonreinforced concrete blocks and cylinders made with various reactive aggregates and stored at 38 °C and >95% relative humidity. The objective of part II was to verify the validity of the relationships from part I for concrete elements made in the laboratory but exposed outside. On average for the 51 blocks and 14 slabs tested, the surface cracking increased with ASR expansion and approached the measured expansion in the case of the most severely exposed sections of the specimens tested. The ratio between the expansion estimated from the surface cracking and the measured expansion varied greatly from one specimen to another (between 0 and 4.3), however. Taking into account the type of reactive aggregate involved did not explain the situation. Despite a variety of reactive aggregates, a quite good relationship (coefficient of linear regression R2 = 0.89) was obtained between the DRI and the ASR expansion for the six blocks cored and tested for DRI and SDT. This relationship is significantly different from those obtained in the laboratory, however. Moreover, the exposed concretes clearly differ from the laboratory concretes regarding the most important defects observed in the DRI test. As in the laboratory, the results obtained from the SDT seem to depend on the type of reactive aggregate involved. Nevertheless, this test globally supplied results with the best agreement with the measured expansion.Key words: aggregates, alkali–silica reaction, concrete expansion, damage rating index, petrography, stiffness damage test, surface cracking.

scholarly journals Development of Enhanced Test Methods to Evaluate Alkalisilica Reaction in Concrete

2021 ◽  
Author(s):  
Noura Sinno
Keyword(s):  
Preventive Measures ◽  
Test Methods ◽  
Standard Test ◽  
Test Method ◽  
The Other ◽  
Field Conditions ◽  
Alkali Silica Reaction ◽  
Test Duration ◽  
Concrete Prism ◽  
Concrete Prism Test

Many preventive measures showed improved performance of concrete against alkali-silica reaction (ASR) based on the concrete prism test (CPT) described in the Canadian and American Standards, CSA A23.2-14A and ASTM C1293. However, research has shown that preventive measures that limited the 2-year expansion in the concrete prism test produced late expansion after 7-15 years when tested in the field. The objective of this research is to understand the possible reasons for this late expansion under field conditions and to come up with modified approach to determine the level of supplementary cementing materials (SCM) needed to mitigate the long-term expansion. The research mainly focuses on studying two possible reasons to explain the late expansion. The first reason is the rate and ultimate hydration of SCM, where their capacity to bind alkalis under CPT could be higher than those under field conditions. The other reason for the late expansion could be the geometry and size of the CPT samples which might reduce the expansion due to the excessive alkali leaching. Larger samples showed less leaching compared to standard prisms. 100-mm cylinders showed higher expansion than 75-mm standard prisms; however, both sample shapes showed similar expansions for one tested aggregate when used with SCM. In addition, the capacity of SCM to bind alkalis was shown to be higher at 38ºC compared to the other two tested temperatures investigated in this study: 23ºC and 60ºC. Samples with SCM at high replacement levels expanded more at 60ºC compared to 38ºC. Due to their reduced leaching compared to prisms, testing cylinders at 60ºC showed accelerated results reducing the testing duration to one year compared to the standard test duration of two years. Moreover, a new way to predict the minimum levels of SCM required to mitigate expansion due to alkali-silica reaction is presented showing better correlation with the field. Finally, a fast and reliable test method is suggested to evaluate the reactivity of mineral fillers by adapting and adopting the current test methods available for ASR testing.

scholarly journals Development of Enhanced Test Methods to Evaluate Alkalisilica Reaction in Concrete

2021 ◽  
Author(s):  
Noura Sinno
Keyword(s):  
Preventive Measures ◽  
Test Methods ◽  
Standard Test ◽  
Test Method ◽  
The Other ◽  
Field Conditions ◽  
Alkali Silica Reaction ◽  
Test Duration ◽  
Concrete Prism ◽  
Concrete Prism Test

Many preventive measures showed improved performance of concrete against alkali-silica reaction (ASR) based on the concrete prism test (CPT) described in the Canadian and American Standards, CSA A23.2-14A and ASTM C1293. However, research has shown that preventive measures that limited the 2-year expansion in the concrete prism test produced late expansion after 7-15 years when tested in the field. The objective of this research is to understand the possible reasons for this late expansion under field conditions and to come up with modified approach to determine the level of supplementary cementing materials (SCM) needed to mitigate the long-term expansion. The research mainly focuses on studying two possible reasons to explain the late expansion. The first reason is the rate and ultimate hydration of SCM, where their capacity to bind alkalis under CPT could be higher than those under field conditions. The other reason for the late expansion could be the geometry and size of the CPT samples which might reduce the expansion due to the excessive alkali leaching. Larger samples showed less leaching compared to standard prisms. 100-mm cylinders showed higher expansion than 75-mm standard prisms; however, both sample shapes showed similar expansions for one tested aggregate when used with SCM. In addition, the capacity of SCM to bind alkalis was shown to be higher at 38ºC compared to the other two tested temperatures investigated in this study: 23ºC and 60ºC. Samples with SCM at high replacement levels expanded more at 60ºC compared to 38ºC. Due to their reduced leaching compared to prisms, testing cylinders at 60ºC showed accelerated results reducing the testing duration to one year compared to the standard test duration of two years. Moreover, a new way to predict the minimum levels of SCM required to mitigate expansion due to alkali-silica reaction is presented showing better correlation with the field. Finally, a fast and reliable test method is suggested to evaluate the reactivity of mineral fillers by adapting and adopting the current test methods available for ASR testing.

Investigations on the Effect of Coating Material and Method on Die Wear in Stamping of Advanced High Strength Steels

2013 ◽  
Author(s):  
Ömer Necati Cora ◽  
Muammer Koç ◽  
Peter J. Blau ◽  
Kunio Namiki
Keyword(s):  
Wear Behavior ◽  
High Strength Steels ◽  
High Strength ◽  
Test Method ◽  
Coating Materials ◽  
Advanced High Strength Steels ◽  
Die Wear ◽  
Die Life ◽  
Metalworking Industry ◽  
Width Measurements

Despite the advantages of advanced high strength steels (AHSS), their stamping into functional lightweight parts demands prolonged die life, which necessitates the use of alternative substrates, coating materials, and/or surface conditioning to minimize and delay the die wear. In order to avoid frequent die replacement and surface quality problems on the stamped parts, the metalworking industry has been investigating various approaches such as reducing/refining the carbide particles, adding alloying elements, and elevating the hardness and toughness values for both substrate materials and coatings. The objective of this work was to investigate the effects of different coatings on the wear behavior of a some selected tool steel materials (die sample of interest) against two different AHSS sheet blanks through a cylinder-on-flat type reciprocating test method. After wear tests, both die sample and sheet blank surface were microscopically examined. Wear resistance of the slider was quantified from wear scar width measurements. Results showed that TD and CVD coated die samples performed better than the two other PVD coated samples.

Residual Stress Measurements in an Autofrettage Tube Using Hole Drilling Method

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Hamid Jahed ◽  
Mohammad Reza Faritus ◽  
Zeinab Jahed
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Hoop Stress ◽  
Test Method ◽  
Test Material ◽  
Hole Drilling ◽  
Hole Drilling Method ◽  
Ring Sample ◽  
Drilling Method ◽  
American Society

Relieved strains due to drilling hole in a ring sample cut from an autofrettage cylinder are measured. Measured strains are then transformed to residual stresses using calibration constants and mathematical relations of elasticity based on ASTM standard recommendations (American Society for Testing and Materials, ASTM E 837-08, 2008, “Standard Test Method for Determining Residual Stresses by the Hole-Drilling Strain-Gage Method,” American Society for Testing and Materials). The hydraulic autofrettage is pressurizing a closed-end long cylinder beyond its elastic limits and subsequently removing the pressure. In contrast to three-dimensional stress state in the autofrettage tube, the stress measurement in hole drilling method is performed on a traction free surface formed from cutting the ring sample. The process of cutting the ring sample from a long autofrettaged tube is simulated using finite element method (FEM) and the redistribution of the residual stress due to the cut is discussed. Hence, transformation of the hole drilling measurements on the ring slice to the autofrettage residual stresses is revealed. The residual stresses are also predicted by variable material properties (VMP) method (Jahed, H., and Dubey, R. N., 1997, “An Axisymmetric Method of Elastic-Plastic Analysis Capable of Predicting Residual Stress Field,” Trans. ASME J. Pressure Vessel Technol., 119, pp. 264–273) using real loading and unloading behavior of the test material. Prediction results for residual hoop stress agree very well with the measurements. However, radial stress predictions are less than measured values particularly in the middle of the ring. To remove the discrepancy in radial residual stresses, the measured residual hoop stress that shows a self-balanced distribution was taken as the basis for calculating residual radial stresses using field equations of elasticity. The obtained residual stresses were improved a lot and were in good agreement with the VMP solution.

scholarly journals Pengaruh Penambahan Abu Arang Tempurung Kelapa Pada Tanah Lempung Terhadap Hasil Uji Kompaksi

2021 ◽  
Vol 3 (2) ◽  
pp. 276-285
Author(s):  
Brigita Suzanna ◽  
Irwan Lie Keng Wong ◽  
Monika Datu Mirring Palinggi
Keyword(s):  
Specific Gravity ◽  
Moisture Content ◽  
Physical Properties ◽  
Clay Soil ◽  
Test Method ◽  
Coconut Shell ◽  
Dry Density ◽  
Coconut Shell Ash ◽  
American Society ◽  
Index Value

The purpose of this research is to determine the physical properties of clay soil and to analyze the effect of adding coconut shell charcoal ash to the clay soil. The soil samples used in this study came from Tanralili District, Maros Regency, two sample points were taken and the variations in the levels of addition of coconut shell charcoal ash is 0%, 4%, 6%, 8%, 10%. The test method used refers to ASTM (American Society for Testing Materials). The tests carried out were testing the physical properties of the soil in the form of moisture content, specific gravity, Atterberg boundaries, filter analysis, and hydrometer analysis, then a compaction test was carried out to determine the maximum soil density. The results of the test obtained a moisture content value of 28.811%, a specific gravity of 2.58 g / cm3 so that it is classified as organic clay. As well as the plasticity index value of 9.926% with moderate plasticity from the 7% -17% interval. Then from the test results of soil compaction testing with the addition of coconut shell ash, the dry density (gdry) equal to 0.862, 0.886, 0.914, 0.943, 0.962, this means that the soil sample experienced an increase in dry density (gdry) of 11.60%. From the research results it can be concluded that the addition of coconut shell charcoal ash can increase the value of soil dry density so that it can be used to increase the value of the carrying capacity of clay soil.

scholarly journals Effect of sample geometry and aggregate type on expansion due to alkali-silica reaction

2021 ◽  
Author(s):  
Noura Sinno ◽  
Medhat Shehata
Keyword(s):  
Alkali Silica Reaction ◽  
Sample Geometry ◽  
Concrete Prism ◽  
Supplementary Cementing Materials ◽  
Field Samples ◽  
Alkali Leaching ◽  
Concrete Prism Test ◽  
Cylindrical Samples

Late expansions due to alkali-silica reaction were observed in field samples for some aggregates and supplementary cementing materials (SCM) combinations despite meeting the 2-year expansion criterion of the concrete prism test. This fosters a research into the effect of sample geometry and aggregate reactivity on alkali leaching and expansion of lab samples. Larger samples showed less leaching compared to standard prisms. Cylinders of 100 mm-diameter showed higher expansion than 75 mm-standard prisms; however, both sample shapes showed similar expansions for one tested aggregate when used with SCM. Alkali leaching from concrete samples and alkali release from some aggregates could lead to cylindrical samples having higher expansion and better correlation to field samples compared to standard concrete prisms.

SHEAR PROPERTY OF STRUCTURAL EPOXY ADHESIVE EXPOSED TO TROPICAL WEATHERING CONDITION

2015 ◽  
Vol 77 (8) ◽  
Author(s):  
Shukur Abu Hassan ◽  
Yob Saed Ismail ◽  
Abdul Rahman Mohd. Sam ◽  
Umar Abdul Hanan ◽  
Mat Uzir Wahit
Keyword(s):  
Structural Integrity ◽  
Elevated Temperatures ◽  
Salt Water ◽  
Epoxy Adhesive ◽  
Test Method ◽  
Plain Water ◽  
Plane Shear ◽  
Shear Properties ◽  
Shear Property ◽  
Epoxy Material

As a consequence of tropical climate featuring abundant rain and sunshine throughout the year, adhesive bonded joints undergo substantial exposure to moisture and elevated temperatures. It is known that the degradation of adhesive materials such as structural epoxy due to weathering could affect the overall bond performance of structural integrity of reinforced concrete such as carbon fibre reinforced polymer composites (CFRP) plate system. The objective of the study is to investigate the in-plane shear properties of structural epoxy material exposed to tropical environmental conditions using Arcan Test Method. The epoxy adhesive was casted in a closed metal mould to produce butterfly shaped specimens. The specimens were exposed to four conditions; laboratory, outdoor, plain water, and salt water. The specimens were tested for shear properties and failed in brittle form. Microstructure analysis was performed to study the fracture surface of the test specimens. The study showed that the tropical exposure conditions influenced the shear strength of the epoxy material, especially for those exposed to plain and salt water conditions, which were 32% lower than the control specimen for specimens exposed to plain water followed by salt water (26.6%), laboratory (25.4%) and finally outdoor (18.4%).

Reliability of Miniature Concrete Prism Test in Assessing Alkali-Silica Reactivity of Moderately Reactive Aggregates

2020 ◽  
Vol 2674 (4) ◽  
pp. 23-29
Author(s):  
Harish Konduru ◽  
Prasad Rangaraju ◽  
Omar Amer
Keyword(s):  
False Positive ◽  
Standardized Test ◽  
False Negative ◽  
Test Method ◽  
Test Procedures ◽  
Concrete Prism ◽  
Coarse Aggregates ◽  
Fine Aggregates ◽  
Mortar Bar ◽  
Concrete Prism Test

Alkali-silica reaction (ASR) is one of the most significant durability issues in concrete structures. Although there are a number of standardized test procedures to evaluate the aggregate reactivity, each method has its own drawbacks. Two of the most common tests that are employed widely are the accelerated mortar bar test (AMBT) (ASTM C1260) and the concrete prism test (CPT) (ASTM C1293). The major issue with the AMBT test is the number of false-positive results from this test associated with high test temperature, rendering the test method unreliable. CPT is one of the most reliable tests for assessing the potential for ASR, but its major disadvantage is the duration of the test involved, which takes one to two years. In this research, a novel test method called the miniature concrete prism test (MCPT) was developed and the effectiveness and reliability of the results assessed when compared with CPT and AMBT. Samples of 26 coarse aggregates and 16 fine aggregates with various reactivity levels were employed for the testing. The test results were compared for MCPT versus CPT, in which 23 out of 26 coarse aggregates and eight out of 16 fine aggregates either passed or failed in both MCPT and CPT. For MCPT versus AMBT, 16 out of 26 coarse aggregates and 13 out of 16 fine aggregates either passed or failed in both MCPT and AMBT. The sensitivity of false-negative and false-positive aggregate sources is discussed and explained briefly.

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