关键词: 混凝土, 硫酸盐侵蚀, 干湿循环, 寿命预测, GM(1,1)模型

Abstract: 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.

Key words: concrete, sulphate erosion, wet-dry cycle, life forecast, GM (1, 1) model