Study on calcium dissolution behavior of manufactured sand concrete

The accelerated calcium dissolution tests of concrete with different replacement rates of manufactured sand (& rho;ms) and different contents of stone powder (& rho;sp) were carried out using the ammonium chloride solution. The results show that the dissolution resistance of manufactured sand concrete (MSC) is higher than that of ordinary concrete, although the & rho;ms and & rho;sp influence its physical and mechanical properties. When the & rho;ms is low, the mass loss ratio and dissolution depth of MSC after dissolution both increase with the increasing & rho;sp. They also increase with the increasing of & rho;ms, but the & rho;sp no longer influences them when the & rho;ms is high. The & rho;sp corresponding to the maximum ultrasonic velocity of MSC is different for the various & rho;ms. The addition of manufactured sand inhibits the reduction of the compressive strength after dissolution, while stone powder has no significant impact on this. Finally, the fitting model of dissolution depth and prediction model of compressive strength of MSC after dissolution are established.