Study of the alkali reactivity of aggregates used in Beijing Available to Purchase

Problems due to alkali–silica reaction have occurred in Beijing and there is an urgent need to detect the alkali reactivity of aggregates being used. The typical sands and coarse aggregates of this area were investigated by ASTM mortar bar test and the ASTM accelerated mortar bar test (AMBT). A pebble (rounded coarse aggregate) from Yongding River (YD) and a gravel from Nankou Mountain (NK), exhibited the potential for alkali–aggregate reaction. It was also found that the content, size distribution of aggregate and the size of samples showed influences on the expansion of mortar bars. The mortar bars made with the pessimum composition of aggregates from YD showed the largest expansion.