Novel admixtures for mitigation of alkali-silica reaction in concrete

The objective of this study is to develop a new generation of alkali-silica reaction (ASR) inhibiting powder additives or liquid chemical admixtures for concrete. Throughout the paper, the word additive primarily refers to a powder while admixture primarily refers to liquid (pre-dissolved powder); otherwise, the two terms are used interchangeably. These additives are cheaper and more abundant than lithium admixtures, yet provide more consistency in terms of quality, supply, and performance in comparison with supplementary cementitious materials (SCMs). A methodical approach was developed to identify such additives that primarily mitigate ASR by reducing the pH of concrete pore solution. The mechanism of pH reduction was identified and the set of criteria that a potential additive must meet were developed. The suitable additives were screened using ASTM C1293 as well as mortar tests to estimate their impact on the performance of concrete. A final list of seven promising additives was identified.