高温效应下MgO-矿粉/粉煤灰固化土强度预测
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摘要
引入活性MgO-矿粉/粉煤灰胶凝材料对黏土进行固化处理,通过无侧限抗压强度试验,开展养护温度、固化剂掺量及配合比等多因素影响下固化黏土抗压强度演变规律研究,评价既有强度预测模型对于考虑温度作用的活性MgO-矿粉/粉煤灰固化黏土的适用性,根据现有试验结果提出了一种基于室内标准养护温度(约20℃)预测高温养护(以40℃和60℃为例)试样强度发展过程的方法.结果表明:高温养护不仅能有效提高试样早期强度,还可显著提高其长期强度;活性MgO-矿粉混合料固化效果明显优于活性MgO-粉煤灰,现有水泥固化黏土强度预测模型并不适用于高温作用下活性MgO-矿粉/粉煤灰固化黏土;针对高温养护试样抗压强度预测所提出的标准化处理方法被证实有效可行,40℃和60℃养护试样强度预测值与实测值拟合相关系数分别高达0.981和0.983.
The reactive MgO-slag/fly ash cementitious materials were incorporated into the clay solidification,and the compressive strength development of solidified clay was investigated to discuss the effect of curing temperature, binder amount and mixing proportion etc. The reliability of the existing strength prediction model for reactive MgO-slag/fly ash stabilized clay under the influence of temperature was evaluated,and a novel strength predication method for samples at a given curing temperature(e.g.,40℃and 60℃) was proposed based on the standard room temperature(≈ 20℃).The obtained results show that the high-temperature curing process not only can effectively improve the short-term strength of solidified samples, but also significantly increase its long-term strength.Reactive MgO-slag outperforms largely reactive MgO-fly ash for solidifying clay.The existing strength prediction model for cement-solidified clay is proved unsuitable for reactive MgO-slag/ash solidified clay subjected to high temperature curing.Especially,the proposed standardized method to facilitate the prediction of compressive strength of samples cured at high temperature turns out to be effective and feasible, and the linear correlation coefficient between predicted and measured values reaches up to 0.981 and 0.983 respectively for samples cured at 40℃ and 60℃.
The reactive MgO-slag/fly ash cementitious materials were incorporated into the clay solidification,and the compressive strength development of solidified clay was investigated to discuss the effect of curing temperature, binder amount and mixing proportion etc. The reliability of the existing strength prediction model for reactive MgO-slag/fly ash stabilized clay under the influence of temperature was evaluated,and a novel strength predication method for samples at a given curing temperature(e.g.,40℃and 60℃) was proposed based on the standard room temperature(≈ 20℃).The obtained results show that the high-temperature curing process not only can effectively improve the short-term strength of solidified samples, but also significantly increase its long-term strength.Reactive MgO-slag outperforms largely reactive MgO-fly ash for solidifying clay.The existing strength prediction model for cement-solidified clay is proved unsuitable for reactive MgO-slag/ash solidified clay subjected to high temperature curing.Especially,the proposed standardized method to facilitate the prediction of compressive strength of samples cured at high temperature turns out to be effective and feasible, and the linear correlation coefficient between predicted and measured values reaches up to 0.981 and 0.983 respectively for samples cured at 40℃ and 60℃.
引文
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[9]章荣军,郑俊杰,程钰诗,等.养护温度对水泥固化淤泥强度影响试验研究[J].岩土力学,2016,37(12):3463-3471.
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[2]SHI C,KRIVENKO P V,ROY D M.Alkali-activated cements and concretes[M].Abingdon:Taylor&Francis,2006.
[3]YI Y,LISKA M,AI-TABBAA A.Properties of two model soils stabilized with different blends and contents of GGBS,Mg O,Lime,and PC[J].Journal of Materials in Civil Engineering,2014,26(2):267-274.
[4]WANG D,WANG H,JIANG Y.Water immersioninduced strength performance of solidified soils with reactive Mg O-a green and low carbon binder[J].Journal of Testing and Evaluation,2019,47(2):1569-1585.
[5]陈萌,杨国录,余亮英.粉煤灰和Na OH固化稳定化受污淤泥试验研究[J].华中科技大学学报:自然科学版,2013,41(10):123-127.
[6]JIN F,GU K,ABDOLLAHZADEH A,et al.Effects of different reactive Mg Os on the hydration of Mg O-activated GGBS paste[J].Journal of Materials in Civil Engineering,2015,27(7):B4014001
[7]BALENDRAN R V,MARTIN-BUADES W H.The influence of high temperature curing on the compressive,tensile and flexural strength of pulverized fuel ash concrete[J].Building and Environment,2000,35(5):415-423.
[8]ZHANG R J,LU Y T,TAN T S,et al.Long-term effect of curing temperature on the strength behavior of cementstabilized clay[J].Journal of Geotechnical&Geoenvironmental Engineering,2014,140(8):04014045.
[9]章荣军,郑俊杰,程钰诗,等.养护温度对水泥固化淤泥强度影响试验研究[J].岩土力学,2016,37(12):3463-3471.
[10]CHITAMBIRA B.Accelerated ageing of cement stabilised/solidified contaminated soils with elevated temperatures[D].Cambridge:Department of Engineering,University of Cambridge,2004.