Alkali-silica reaction (ASR) and alkali-carbonate reaction (ACR) in activated blast furnace slag cement (ABFSC) concrete

Abstract

This paper examines the dimensional change of concrete prisms that were fabricated using concrete made with either sodium silicate or sodium carbonate ABFSC binder incorporating either an innocuous control aggregate, an aggregate that is known to be reactive by way of ASR or ACR in ordinary Portland cement (OPC) concrete or an aggregate that contains reactive silica although a good service record has been exhibited. The concrete prism test procedures detailed in the Canadian Standards Association (CSA A23.2-14A-94) specifications were used. The results of a parallel study of the early dimensional stability of ABFSC concrete which involved petrographic examination of concrete thin sections are discussed. It was found that, although ABFSC concrete is more vulnerable to ACR, it is less susceptible to expansion due to ASR than OPC concrete, however, expansions after one year can still be unacceptable. Unlike OPC, many large cavities form within the paste structure of ABFSC mixtures at early ages which is accompanied by shrinkage. This behaviour must be considered in the analysis.