Experimental and modelling research of the accelerated calcium leaching of cement paste in ammonium nitrate solution

Calcium leaching of cement-based materials is of concern for scientific and application significance. Considering the altered solid-liquid equilibrium curve, an accelerated calcium leaching model of pure cement paste in 6 mol/L ammonium nitrate leaching solution was built up in this research. The model was numerically solved using finite difference method, and the influences of w/c ratio and initial cement composition on leaching were addressed. The accelerated model was further verified using elemental distributions and leaching fronts. Besides, through comparing the accelerated model in 6 mol/L ammonium nitrate solution and the un-accelerated model in deionized water, an accelerated factor of about 130 was found, which was slightly influenced by the initial material compositions. (C) 2012 Elsevier Ltd. All rights reserved.