硫酸盐干湿循环下纤维混凝土的耐久性及寿命

针对西部寒旱盐碱地区环境下的混凝土侵蚀破坏机理，设计制作了0、10%、20%、30%粉煤灰掺量的纤维混凝土试件（纤维掺量同为0.9%），进行两组硫酸盐干湿循环试验（组一：0粉煤灰掺量在2%、5%、10%硫酸钠溶液干湿循环；组二：0、10%、20%、30%粉煤灰掺量在5%硫酸钠溶液干湿循环）。分析研究了试件的质量、抗压强度和劈拉强度的变化规律，采用GM(1, 1)模型模拟了抗压强度耐蚀系数变化规律，预测不同条件下混凝土服役寿命。结果表明，10%硫酸钠溶液的侵蚀速度快于2%和5%浓度硫酸钠溶液；10%的粉煤灰掺入可以减缓纤维混凝土抗压强度下降速度，增强其耐久性；GM(1, 1)模型预测结果表明10%粉煤灰掺量混凝土寿命优于其他三组，与试验结果相符。

Durability and service life of fiber concrete with sulfate admixtures under wet-dry cycling

Based on the concrete erosion mechanism in the cold, dry and saline-alkali areas in the western China, we design and prepare fiber concrete specimens with fly ash contents of 0%, 10%, 20% and 30% (with the same fiber content of 0.9%) and conduct two sets of sulfate addition and wet-dry cycling tests: Set I with no fly ash and sodium sulfate solutions of 2%, 5% and 10%; Set II with fly ash contents of 0, 10%, 20% and 30% and sodium sulfate solution of 5%. We examine variations in the mass, compressive strength and splitting tensile strength of the specimens, simulate the trends of the corrosion resistance coefficient of compressive strength using the GM (1, 1) model, and predict the service life of concrete under different conditions. The results show the eroding rate of 10% sodium sulfate solution is faster than that of 2% or 5% solution. Adding 10% fly ash can slow down the decline of compressive strength of fiber reinforced concrete and enhance its durability. The GM (1, 1) predictions show the service life of concrete with 10% fly ash is longer than the other three contents, agreeing well with the test results.