Effects of Acid Rain on Concrete by Shaodong Xiea, *, Li Qia, Ding Zhoub

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ARTICLE IN PRESS Atmospheric Environment 38 (2004) 4457–4466 Investigation of the effects of acid rain on the deterioration of cement concrete using accelerated tests established in laboratory Shaodong Xiea,*, Li Qia, Ding Zhoub a Department of Environmental Science, State Key Joint Laboratory of Environmental Simulation and Pollution Control, Peking University, Beijing 100871, China b Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001, China Received 8 January 2004; accepted 26 May 2004 Abstract Deterioration of cement concrete specimens caused by simulated acid rain was investigated by laboratory tests. Before and after cement concrete specimens were exposed to simulated acid rain, the neutralized depth, the compressive strength and the chemical compositions in the hardened cement paste were measured. The mineralogical composition of the concrete specimens was analyzed with XRD. The results lead to the following conclusions: the neutralized depth of the concrete specimens of all experiments can be described as a power function of exposure duration, CaO loss and the reduction rate of strength increased with H+ and decreased with SO2À concentration in simulated acid rain. The 4 original mineral compounds such as [Na K]AlSi3O8 and [Ca Na][SiAl]4O8 in the hardened cement paste are converted to CaSO4 Á 2H2O, CaAl2Si2O8 and Ca3Al6O12 Á CaSO4. And these are larger in volume so that the reaction with SO2À 4 ions result in volume expansion and strength decrease. The reduction rate of strength has a binary linear relation to the CaO loss rate and the ratio of SO3 content to CaO content in the hardened cement paste. So the deterioration of acid rain on the concrete specimen is caused by both H+ dissolution and SO2À expansion. 4 r 2004 Elsevier Ltd. All rights reserved. Keywords: Acid rain; Cement concrete;

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