scholarly journals Alkali-Wrapped Concrete Prism Test (AW-CPT) – New Testing Protocol Toward a Performance Test against Alkali-Silica Reaction–

2018 ◽  
Vol 16 (9) ◽  
pp. 441-460 ◽  
Author(s):  
Yuichiro Kawabata ◽  
Kazuo Yamada ◽  
Yasutaka Sagawa ◽  
Shoichi Ogawa
Keyword(s):  
Performance Test ◽  
Alkali Silica Reaction ◽  
Concrete Prism ◽  
Testing Protocol ◽  
Concrete Prism Test ◽  
A Performance

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.

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 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.

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 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.

Divergence between Performance in the Field and Laboratory Test Results for Alkali-Silica Reaction

2020 ◽  
Vol 2674 (5) ◽  
pp. 120-134
Author(s):  
Jussara Tanesi ◽  
Thano Drimalas ◽  
Krishna Siva Teja Chopperla ◽  
Mengesha Beyene ◽  
Jason H. Ideker ◽  
...  
Keyword(s):  
Cementitious Materials ◽  
Test Methods ◽  
Supplementary Cementitious Materials ◽  
Long Term Results ◽  
Alkali Silica Reaction ◽  
Lithium Nitrate ◽  
Concrete Prism ◽  
Laboratory Test Results ◽  
Mortar Bar ◽  
Concrete Prism Test

The most common test methods used to evaluate alkali-silica reaction (ASR) are the concrete prism test (CPT) and the accelerated mortar bar test (AMBT). However, these tests were not found to be entirely reliable in predicting the performance of concrete under field conditions, especially when supplementary cementitious materials (SCMs) are used. Recently, two new test methods, the miniature concrete prism test (MCPT) and the concrete cylinder test (CCT), have been proposed but still need to be benchmarked with results from outdoor exposed blocks. In this paper, the results from the MCPT, CCT, CPT and exposed blocks are compared and their ability to properly evaluate the expected behavior of these mixtures in service with regard to ASR is discussed. Here, the results of mixtures made with four reactive aggregates: Spratt, Placitas (coarse aggregates), Wright, and Jobe (fine aggregates) and SCMs (fly ashes Classes F or C, slag cement, or silica fume) at different levels of cement replacement or lithium nitrate are presented. For these mixtures, only the MCPT was capable of properly classifying the efficiency of the ASR preventive measures, as compared with the long-term results obtained from the exposed blocks.

The construction of a performance test.

2006 ◽  
pp. 272-334
Author(s):  
J. Crosby Chapman
Keyword(s):  
Performance Test ◽  
A Performance
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