应力、碳化及酸雨作用下混凝土中性化试验研究

Experimental study on the concrete neutralization under stress and carbonization and acid rain

考虑酸雨、碳化和荷载等单一因素及多因素耦合作用下混凝土构件中性化的影响因子,对室内快速劣化试验进行设计与研究。通过模拟酸雨侵蚀和碳化作用对无应力、弯曲应力和轴心压应力混凝土试件进行相应试验,研究多因素作用下混凝土构件的中性化规律及耦合效应。试验结果表明,碳化和酸雨存在耦合现象,酸雨在某种程度上抑制碳化作用,酸雨和碳化耦合系数小于1,混凝土中性化各因素影响由低到高依次为dS<dST<dT<dTS<d(T+S);无论酸雨、碳化等单一因素或多因素耦合作用,混凝土中性化深度值都与时间平方根呈正比关系;拉应力可促进混凝土中性化,而压应力抑制其中性化,应力与混凝土中性化深度值之间呈近似线性关系,并通过试验数据拟合出不同腐蚀模式下的应力影响因子。

Considering the factors such as the effects of acid rain,carbonization and external load and the interactions of concrete component's neutralization,an indoor rapid deterioration test scheme was designed and conducted. The neutral rules and the coupling effects of concrete components were studied by simulating acid rain erosion and fast carbonization of the concrete components without stress, with flexural stress and axial stress. Experimental results show that carbonization and acid rain coupling exists and the acid rain inhibits the carbonization to some extent. The coupling coefficient of acid rain and carbonization is less than 1. Effects of various factors on the neutralization of concrete from low to high are dS< dST< dT< dTS< d( T+S). No matter what acid rain,carbonization or their coupling interaction,the carbonation depth value of concrete increases with erosion time. The neutral velocity is fast in the early stage and slows down with the passage of time. The neutral depth is proportional to the square root of time. The tensile stress can promote the neutralization of concrete,while the compressive stress inhibits it. The relationship between the stress and concrete neutral depth value is approximately linear. Different corrosion mode stress factors are fit by the test data.