预湿轻骨料对甘肃河西地区混凝土收缩开裂性能影响
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摘要
为解决甘肃河西地区混凝土构筑物早期收缩开裂问题,以预湿轻骨料作为内养护材料,通过室内模拟河西地区气候条件,研究了预湿轻骨料对混凝土抗压强度、自收缩、干燥收缩以及毛细管负压等性能的影响。结果表明:预湿轻骨料可以有效改善河西地区气候条件下的混凝土收缩开裂问题;但预湿轻骨料会对混凝土强度产生不利影响,应对其掺量加以控制;预湿页岩陶粒的内养护效果要好于预湿粉煤灰陶粒,且页岩陶粒引入水量为内养护水量的70%时,对混凝土内养护效果最佳。
To solve the problem of early shrinkage cracking of concrete structure in Hexi area of Gansu Province,used pre-wetted lightweight aggregates as internal curing material,simulated the weather conditions in the Hexi area through the laboratory,the effect of pre-wetted lightweight aggregates on the compressive strength,autogenous shrinkage,dry shrinkage and meniscus depression of concrete was studied. Test results show that the pre-wetted lightweight aggregates can effectively improve the shrinkage and cracking of concrete under the climatic conditions in the Hexi area. However,the pre-wetted lightweight aggregates will have an adverse effect on the strength of the concrete,and the amount of prewetted lightweight aggregates shall be controlled. The pre-wetted shale haydite has better internal curing effect than the pre-wetted fly ash ceramsite,and the shale haydite introduces 70% of curing water,which has the best curing effect in the concrete.
To solve the problem of early shrinkage cracking of concrete structure in Hexi area of Gansu Province,used pre-wetted lightweight aggregates as internal curing material,simulated the weather conditions in the Hexi area through the laboratory,the effect of pre-wetted lightweight aggregates on the compressive strength,autogenous shrinkage,dry shrinkage and meniscus depression of concrete was studied. Test results show that the pre-wetted lightweight aggregates can effectively improve the shrinkage and cracking of concrete under the climatic conditions in the Hexi area. However,the pre-wetted lightweight aggregates will have an adverse effect on the strength of the concrete,and the amount of prewetted lightweight aggregates shall be controlled. The pre-wetted shale haydite has better internal curing effect than the pre-wetted fly ash ceramsite,and the shale haydite introduces 70% of curing water,which has the best curing effect in the concrete.
引文
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[2]Liu F,Wang J,Qian X,et al.Internal curing of high performance concrete using cenospheres[J].Cement&Concrete Research,2017,95:39-46.
[3]郑小波.不同干燥条件对预湿轻细骨料内养护混凝土性能的影响[D].北京:清华大学,2015.
[4]Henkensiefken R,Nantung T,Weiss W J.Reducing restrained shrinkage cracking in concrete:examining the behavior of self-curing concrete made using different volumes of saturated lightweight aggregate[C].2008 Concrete Bridge Conference,2008.
[5]Lura P,Bisschop J.On the origin of eigenstresses in lightweight aggregate concrete[J].Cement&Concrete Composites,2004,26(5):445-452.
[6]Cusson D,Lounis Z,Daigle L.Benefits of internal curing on service life and life-cycle cost of high-performance concrete bridge decks-a case study[J].Cement&Concrete Composites,2010,32(5):339-350.
[7]Zhutovsky S,Kovler K,Bentur A.Revisiting the protected paste volume concept for internal curing of high-strength concretes[J].Cement&Concrete Research,2011,41(9):981-986.
[8]Crocker D A.Lightweight cementitious formulations and processes.USA:US5472499[P].1995.
[9]张珍林.高吸水性树脂对高强混凝土早期减缩效果及机理研究[D].北京:清华大学,2013.
[10]万广培,李化建,黄佳木.混凝土内养护技术研究进展[J].混凝土,2012(7):51-54.
[11]ASTM,C1698-09:Standard test method for autogenous strain of cement paste and mortar[S].West Conshohocken,PA,2014.
[12]田倩,王育江,李磊,等.一种基于孔隙负压测试的混凝土早期养护方法[J].建筑材料学报,2013,16(4):587-591.