碾压混凝土渗透溶蚀规律及其机理分析

Mechanic analysis and rules of permeability and corrosion in granding concrete

在混凝土的原材料及龄期相同的情况下 ,配合比和水压是影响碾压混凝土抗渗溶蚀性能的关键。溶出物的种类由碾压混凝土的配合比决定 ,溶出物 (或吸收物 )的数量 ,主要决定于配合比与压力。Ca O/Si O2 摩尔比为 1或接近于 1,且含足够数量的胶凝材料的碾压混凝土 ,具有最佳的抗渗溶蚀性能。当 Ca O/Si O2 >1时 ,混凝土出现缺硅现象 ,而 Ca O/Si O2 <1时 ,则出现缺钙现象。因此 ,碾压混凝土中粉煤灰的加入量应满足 Ca O/Si O2 摩尔比接近1或稍大于 1这一必要条件。无论何种配合比 ,在水压力为定值时 ,单位体积混凝土中 Ca O或 Si O2 的日均溶蚀量均随时间的延长呈下降趋势 ,而随压力逐渐升高呈上升趋势。

Under the same condition of raw materials and age,ratio and hydrauic gradiant is the key influencing permeability and corrosion ability of the granding concrete.The kinds of the dissoiulted substances is determined by ratio of the granding concrete,but amount of the dissoluted substances is determined by ratio and hydrauic gradiant.When moiar ratio of CaO/SiO 2 is 1 or near 1 in granding concrete,moreover granding concrete contain adequate binying materids,anti permeability and corrosion ability is optimal.When molar ratio of CaO/SiO 2>1,phenomenon being short of Si exists,however,when CaO/SiO 2<1,pheomenon being short of Ca exists,therefore,quantity of fly ash in granding concrete should meet CaO/SiO 2≈1.When water pressure is certain,dissolve corrosion per day of CaO or SiO 2 in unit volume concrete.Presents decreasing trend along with time prolonging,but pressure gradually presents increasing trend.