Performance of Structural Concrete Containing Sedimentary Rocks

Abstract In 2014, Singapore commissioned the Jurong Rock Caverns (JRC) for the storage of liquid hydrocarbons. The construction of this first commercial underground storage facility in Southeast Asia had extracted about four million cubic metres of rocks which comprised mainly sedimentary rocks (SR). To offset the development costs of JRC and reduce the heavy reliance on imported natural aggregates, studies were conducted to evaluate its applications in construction. One of the studies had shown that it could be processed into aggregates for road construction. However, SR aggregates were found to be susceptible to the alkali-silica reaction (ASR) which posed a concern for concrete production. A preliminary study was carried out to find a way to mitigate this phenomenon and the introduction of ground granulated blast-furnace slag (GGBS) yielded the best outcome. Further study was undertaken to investigate various concrete mixes that contained 100% SR aggregates and different replacement levels of ordinary Portland cement (OPC) with GGBS. The structural performance of these mixes was assessed through a series of mechanical tests. The test results demonstrated that GGBS was effective in suppressing the ASR-induced expansions and meeting the specifications of structural concrete. Comparable performance was also observed when the proposed mixes containing up to 50% GGBS were benchmarked against the conventional concrete made up of granite aggregates and OPC. This study has led to the development of a new and sustainable construction material in Singapore which offers an alternative to the imported aggregates and a circular economy approach to alleviate the pressing issue of landfill.