A Rapid Autoclave Mortar Bar Method to Determine the Potential Alkali-Silica Reactivity of St. Lawrence Lowlands Carbonate Aggregates (Quebec, Canada)

1991 ◽  
Vol 13 (1) ◽  
pp. 58 ◽  
Author(s):  
PK Mehta ◽  
B Fournier ◽  
M-A Berubé ◽  
G Bergeron
Keyword(s):  
Alkali Silica Reactivity ◽  
Mortar Bar

scholarly journals Accelerated test methods for evaluating alkali-silica reactivity of recycled concrete aggregates

2021 ◽  
Author(s):  
Robert C Johnson
Keyword(s):  
Binding Capacity ◽  
Recycled Concrete ◽  
Test Duration ◽  
Accelerated Tests ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Alkali Silica Reactivity ◽  
Accelerated Mortar Bar Test ◽  
Bar Test ◽  
Mortar Bar

This thesis reports the findings of a study carried out to determine the effectiveness of Accelerated Tests in evaluating the Alkali-Silica Reactivity of Recycled Concrete Aggregates. The study evaluated the variability of the Accelerated Mortar Bar Test due to test variables as well as the single and multi-laboratory variation. The variability of the Concrete Microbar Test due to test variables and the correlation to results from Accelerated Mortar Bar and Concrete Prism Test results were also evaluated. The tests were corroborated by comparing the porosity, permeability and alkali binding capacity of samples tested by the accelerated tests. It was found that the Accelerated Mortar Bar Test provides acceptable results when the test variables, such as crushing methods and absorption values, are carried out and evaluated properly. The Concrete Microbar Test was found to underestimate the expansion of reactive aggregates. However, the same test was found to provide good correlation to the expansion results of Concrete Prisms incorporating Supplementary Cementing Materials when the test duration was increased.

Effects of Geopolymer Concrete Fly Ash Based on Alkali Silica Reaction (ASR)

2014 ◽  
Vol 567 ◽  
pp. 405-410 ◽  
Author(s):  
Muhd Fadhil Nuruddin ◽  
Siti Nooriza Abd. Razak
Keyword(s):  
Fly Ash ◽  
Chemical Reaction ◽  
Length Change ◽  
Alkali Silica Reaction ◽  
Geopolymer Concrete ◽  
Alkali Silica Reactivity ◽  
Mortar Bar ◽  
Class F Fly Ash ◽  
Strength And Durability ◽  
Standard Limit

Alkali Silica Reaction (ASR) is a chemical reaction which affects both strength and durability of concrete. ASR occurs due to a chemical reaction between alkali oxides presents in the cement paste and reactive silica in aggregate. This reaction could lead to the volume expansion, cracking, loss of strength and potential failure of the concrete. This research aimed to investigate the potential alkali silica reactivity on geopolymer concrete. Specimens were prepared using Class F fly ash as binder while sodium hydroxide and sodium silicate as alkaline activators. ASTM C1260 was adopted to determine potential alkali silica reactivity by measuring the length change of mortar bar as well as the decrease in compressive strength test. Results show that fly ash based geopolymer concrete is less vulnerable to ASR as the expansion of mortar bar is below the threshold of ASTM standard limit which is 0.10% of expansion. In term of strength, the geopolymer concrete did not reduced instead it increased. From the results, it has indicated that both tests ensure that the durability of geopolymer concrete is excellent and can withstand a long life span.

Applicability of the Accelerated Mortar Bar Test for Alkali-Silica Reactivity of Recycled Concrete Aggregates

2013 ◽  
Vol 2 (1) ◽  
pp. 20120030 ◽  
Author(s):  
Matthew P. Adams ◽  
Angela Jones ◽  
Sean Beauchemin ◽  
Robert Johnson ◽  
Benoit Fournier ◽  
...  
Keyword(s):  
Recycled Concrete ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Alkali Silica Reactivity ◽  
Accelerated Mortar Bar Test ◽  
Bar Test ◽  
Mortar Bar

scholarly journals The Efficacy of Accelerated Test Methods to Evaluate Alkali Silica Reactivity of Recycled Concrete Aggregates

2021 ◽  
Author(s):  
Medhat Shehata ◽  
Robert Johnson
Keyword(s):  
Test Methods ◽  
Recycled Concrete ◽  
Accelerated Tests ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Supplementary Cementing Materials ◽  
Alkali Silica Reactivity ◽  
Accelerated Mortar Bar Test ◽  
Bar Test ◽  
Mortar Bar

The effectiveness of accelerated tests in evaluating the Alkali-Silica Reactivity of Recycled Concrete Aggregates was evaluated. The Accelerated Mortar Bar Test was found effective for evaluating potential alkali-reactivity when the test variables, such as crushing method and absorption, are carried out in a well-defined process. The method of crushing was found to have significant impact on the expansion. The Concrete Microbar Test (CMBT) provides good correlation to the expansion of Concrete Prisms incorporating Supplementary Cementing Materials when an expansion limit of 0.10% at 56 days or 0.04% at 28 days were used, based on the limited number of tests carried out here.

scholarly journals The Efficacy of Accelerated Test Methods to Evaluate Alkali Silica Reactivity of Recycled Concrete Aggregates

2021 ◽  
Author(s):  
Medhat Shehata ◽  
Robert Johnson
Keyword(s):  
Test Methods ◽  
Recycled Concrete ◽  
Accelerated Tests ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Supplementary Cementing Materials ◽  
Alkali Silica Reactivity ◽  
Accelerated Mortar Bar Test ◽  
Bar Test ◽  
Mortar Bar

The effectiveness of accelerated tests in evaluating the Alkali-Silica Reactivity of Recycled Concrete Aggregates was evaluated. The Accelerated Mortar Bar Test was found effective for evaluating potential alkali-reactivity when the test variables, such as crushing method and absorption, are carried out in a well-defined process. The method of crushing was found to have significant impact on the expansion. The Concrete Microbar Test (CMBT) provides good correlation to the expansion of Concrete Prisms incorporating Supplementary Cementing Materials when an expansion limit of 0.10% at 56 days or 0.04% at 28 days were used, based on the limited number of tests carried out here.

scholarly journals Accelerated test methods for evaluating alkali-silica reactivity of recycled concrete aggregates

2021 ◽  
Author(s):  
Robert C Johnson
Keyword(s):  
Binding Capacity ◽  
Recycled Concrete ◽  
Test Duration ◽  
Accelerated Tests ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Alkali Silica Reactivity ◽  
Accelerated Mortar Bar Test ◽  
Bar Test ◽  
Mortar Bar

This thesis reports the findings of a study carried out to determine the effectiveness of Accelerated Tests in evaluating the Alkali-Silica Reactivity of Recycled Concrete Aggregates. The study evaluated the variability of the Accelerated Mortar Bar Test due to test variables as well as the single and multi-laboratory variation. The variability of the Concrete Microbar Test due to test variables and the correlation to results from Accelerated Mortar Bar and Concrete Prism Test results were also evaluated. The tests were corroborated by comparing the porosity, permeability and alkali binding capacity of samples tested by the accelerated tests. It was found that the Accelerated Mortar Bar Test provides acceptable results when the test variables, such as crushing methods and absorption values, are carried out and evaluated properly. The Concrete Microbar Test was found to underestimate the expansion of reactive aggregates. However, the same test was found to provide good correlation to the expansion results of Concrete Prisms incorporating Supplementary Cementing Materials when the test duration was increased.

Mitigation of Alkali-Silica Reactivity in New Mexico

2000 ◽  
Vol 1698 (1) ◽  
pp. 9-16 ◽  
Author(s):  
R. Gordon McKeen ◽  
Lary R. Lenke ◽  
Kiran K. Pallachulla ◽  
William L. Barringer
Keyword(s):  
New Mexico ◽  
Screening Tests ◽  
Lithium Nitrate ◽  
University Of New Mexico ◽  
State Highway ◽  
Alkali Silica Reactivity ◽  
Continuous Problems ◽  
Materials Research ◽  
New Material ◽  
Mortar Bar

The research experiments reported were conducted at the Materials Research Center, ATR Institute, University of New Mexico, at the request of the Research Bureau, New Mexico State Highway and Transportation Department (NMSHTD). The purpose was to determine the amount of additives required for mitigation of alkali-silica reactivity (ASR) based on screening tests. Fly ash additives routinely used in New Mexico and a new material—lithium nitrate—proposed by the Strategic Highway Research Program were evaluated. The work was motivated by continuous problems with early deterioration of concrete structures due to alkali-silica reactivity. The work was based on the use of acceptance criteria established by NMSHTD for expansion due to ASR, as measured in screening tests. Recommendations resulting from this research do not consider all aspects of the behavior of concrete mixtures and structures. The additive recommendations are based on reduction in mortar-bar expansion during accelerated tests.

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