为了研究硫酸盐冻融循环作用下沙漠砂混凝土(DSC)抗冻性能及强度规律,以不同质量分数硫酸盐溶液(3％、5％、7％Na2SO4)为冻融介质进行冻融循环试验,分析硫酸盐冻融下DSC表观特征、质量损失率、相对动弹性模量、抗蚀系数、超声波速损失率变化规律;建立硫酸盐冻融下沙漠砂混凝土 G M(1,1)强度预测模型.研究结果表明,随着冻融循环次数增加,混凝土质量损失率、超声波速损失率增大,抗蚀系数与相对动弹性模量降低.沙漠砂替代率(DSRR)从0增至40％时混凝土表现出较好抗冻性能;当DSRR为60％时,过量沙漠砂的掺入对混凝土抗冻性能产生不利影响.较大质量分数硫酸盐溶液加剧混凝土破坏,降低了预测寿命.GM(1,1)模型预测结果平均相对误差小于2％,具有较好预测精度,可为西北地区硫酸盐冻融环境下混凝土结构服役评估提供参考.
Research on frost resistance of desert sand concrete undersulphate freeze-thawing and prediction model of strength based on GM(1,1)model
In order to study the frost resistance and strength regulation of desert sand concrete(DSC)subjected to sulphate freeze-thaw cycle,the freeze-thaw cycle test of DSC was carried out with three kinds of sulphate so-lutions(3％,5％and 7％Na2SO4)as freezing and thawing medium.The apparent characteristics,mass loss rate,relative dynamic elastic modulus,corrosion resistance coefficient and ultrasonic velocity loss rate of DSC after exposure to sulphate freeze-thaw cycles were analyzed.A prediction model for the strength of desert sand concrete after sulphate freeze-thawing was established on the basis of GM(1,1)model.Experimental results showed that with increasing number of freeze-thaw cycles,the mass loss rate and ultrasonic velocity loss rate increased,but the corrosion coefficient and relative dynamic modulus decreased.When desert sand replacement rate(DSRR)increased from 0 to 40％,concrete showed better frost resistance.When the DSRR was above 60％,the incorporation of excess desert sand had adversely effect on the frost resistance.Excessive larger mass fraction of sulphate solution exacerbated the failure process of DSC and reduced significantly the predicted serv-ice life of DSC.The average relative errors of the predicated results from GM(1,1)model were less than 2％with high prediction accuracy.Research results provided references for the assessment of the predicted service life of concrete structure under the action of sulphate freeze-thawing in Northwest China.
万方数据
维普
