Influence of sodium hydroxide solution on the physico-mechanical parameters of limestone and dolostone on the concrete durability

Document Type : Review Articles

Authors

1 Housing and Building National and Research Center (HBNRC), Cairo, Egypt

2 Chemistry Department, Faculty of Science, Ain Shams University, Cairo, Egypt

Abstract

The main purpose of this study is to create models that can predict how much concrete with alkali-reactive particles will expand and also study the physical and chemical properties of aggregates at the age of 270 days immersed in tap water and the durability of concrete containing aggregates against 1N of sodium hydroxide solution at the age of 9 months to determine the extent of the effect of alkali on aggregates and their ability to resist. The physico-mechanical properties of four aggregates, two of them were limestone (E) collected from the El Alameen area and the other part were dolostone (A) collected from Ataqaa area and the effect of alkali-reactive siliceous limestone and dolostone recovered on concrete prism test (CPT) under the conditions of ASTM standard test C1293 are investigated in this research. The aggregates studied have a more compacted interface transition zone, according to SEM photographs (ITZ). Samples (E1) and (A1) gave the least linear expansion of the concrete prism test at 9 months, thus these samples achieved the highest improvement of physico-mechanical properties. Samples (E2) and (A2) caused increasing in the linear expansion in the concrete prism and therefore caused a reduction of concrete compressive strength due to the high content of silica gel. All E and A samples showed the low resistivity in 1N NaOH up to 9 months of immersion and the results of SEM examination proved that the interfacial transition zone (ITZ) of E1 and A1 is stronger than the other samples. Concretes composed of limestone (E) aggregates seems to have a greater influence on enhancing mechanical properties than concretes formed of dolostone (A) aggregates. Limestone aggregate appears to be the best choice for improving concrete's physico-mechanical properties and alkali aggregate reactivity, according to the findings.

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Egyptian Journal of Chemistry
Volume 65, Issue 132 - Serial Number 13
Special Issue: Chemistry and Global Challenges (Part B)
December 2022
Pages 1269-1280

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History

  • Receive Date: 25 July 2022
  • Revise Date: 13 August 2022
  • Accept Date: 14 August 2022

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