Effects of Shell and Calcium Carbonate on Properties of Portland Cement

摘要

Different amounts of shell and CaCO_3 were added into the Portland cement, their influences on the compressive strength, sulfate corrosion resistance, hydration heat and porosity of the hardened cement paste were studied. Results show that with the increasing of shell content, the compressive strength decreases, however, modest reduction; as the increase of CaCO_3 content, the strength first increases and then decreases, the compressive strength reaches the highest value when the content is 15%. After addition of shell and CaCO_3, the initial hydration reaction rate accelerates, meanwhile the induction period and acceleration period are brought forward. With the raising of shell and CaCO_3 content, the corrosion resistance coefficient increases gradually, and the sulfate corrosion resistance increases as well. The proportion of the harmless hole which diameter is smaller than 50nm increases after adding the shell and CaCO_3, it's beneficial to improve the performance of concrete.