应用灰色系统理论预测硫酸盐侵蚀环境下混凝土的强度劣化规律及服役寿命(英文)

APPLICATION OF THE GREY SYSTEM THEORY TO PREDICT THE STRENGTH DETERIORATION AND SERVICE LIFE OF CONCRETE SUBJECTED TO SULFATE ENVIRONMENT

制备了水胶比分别为0.32,0.40和0.48的纯水泥混凝土试件,水胶比0.32,粉煤灰掺量10%或20%的粉煤灰混凝土试件,矿粉掺量15%或30%的矿粉混凝土试件,粉煤灰和早强剂掺量分别为20%和1%的含早强剂粉煤灰混凝土试件,及粉煤灰和矿粉掺量分别为15%和15%的混凝土试件。将混凝土试件暴露于干湿循环–硫酸盐加速侵蚀环境中,测试试件抗压强度的演变规律。采用灰色关联理论研究了硫酸盐浓度、水胶比、矿物掺合料及外加剂等因素对混凝土抗压强度的影响。通过建立多元灰预测模型分析了硫酸盐侵蚀环境下混凝土的强度劣化规律及服役寿命。结果表明:强度影响因素的灰色关联度由大到小的排序为:水胶比,硫酸盐浓度,测试龄期,粉煤灰掺量,矿粉掺量,早强剂掺量。多元灰预测模型呈现出较高的精度以预测硫酸盐侵蚀环境下混凝土的强度劣化规律和服役寿命。

Concrete specimens made with ordinary Portland cement at different water–binder ratio （0.32, 0.40 and 0.48） or ordinary Portland cement at water-binder ratio of 0.32 incorporating 10% fly ash （FA） or 20% FA, 20% FA and 1% early strength agent, ground blast furnace slag （GBFS） with the replacement of 15% or 30%, or 15% FA and 15% GBFS were made and exposed to a wetting–drying sulfate environment. Compressive strength of specimens was measured. Effects of sulfate concentration, water-binder ratio, mineral admixtures and chemical additives on the compressive strength of concrete were studied through the grey relational analysis. Multivariate grey prediction model was established to predict the strength development and service life of concrete subjected to sulfate environment. The results indicate that the importance degree of these effective variables from high to low is ranked by water-binder ratio, solution concentration, test age, FA content, GBFS content, early strength agent content. Multivariate grey prediction model shows enough precision to predict the strength development and service life of concrete subjected to sulfate environment.