自密实沙漠砂贫混凝土饱水冰冻后的力学及耗散能特征研究  

Study on mechanical and dissipative energy characteristics of self-compacting desert sand lean concrete desert after saturated freezing

作　　者：关英林 邹承君 杨宝平 康亚明 GUAN Yinglin;ZOU Chengjun;YANG Baoping;KANG Yaming(Chemical Science and Engineering College,North Minzu University,Yinchuan 750021,China;School of Electromechanical Engineering,North Minzu University,Yinchuan 750021,China;Ningxia Yueyuan Engineering Co.,Ltd.,Guyuan 750000,China)

机构地区：[1]北方民族大学化学与化学工程学院,宁夏银川750021 [2]北方民族大学机电工程学院,宁夏银川750021 [3]宁夏跃元工程有限公司,宁夏固原750000

出　　处：《混凝土》2024年第3期1-5,共5页Concrete

基　　金：国家自然科学基金(51569001);北方民族大学校企联合横向项目(2102000247)。

摘　　要：为了研究自密实沙漠砂贫混凝土饱水冰冻后的力学性能,开展了饱水后的低温冰冻试验,并与干燥状态和饱水状态下的试验结果进行了对比,结果表明:(1)单轴抗压强度较干燥时提升了2.6~5.2倍,较饱水时提升了3.8~8.9倍,弹性模量较干燥时提升了1.2~1.8倍,较饱水时提升了1.7~1.9倍,强度的提升幅度要大于弹性模量的提升幅度,延性系数及耗能系数都略有提高;(2)随着水泥掺入量的增大,强度逐渐增大,但是峰值应变逐渐减小,说明强度在提高的同时其脆性也在增强,延性在下降,与相同配合比的干燥试块和饱水试块相比,饱水冰冻试块的峰值应变较大,说明在低温下其延性有所提高;(3)饱水冰冻后强度和刚度提升的内在机理是冰贡献了一部分强度和刚度,可能是微孔隙中的水结冰后成为了试块的一部分,相当于提高了混凝土的密实度,并且水冻结后提高了骨料颗粒间的黏聚力和咬合力。In order to study the mechanical properties of self-compacting desert sand lean concrete after freezing in water,low-temperature freezing tests after freezing in water were carried out,and the results were compared with those in dry and saturated conditions.The results showed that(1)Uniaxial compressive strength increased from 2.6 times to 5.2 times compared with dry condition and from 3.8 times to 8.9 times compared with that in saturated conditions.The elastic modulus increased from 1.2 times to 1.8 times compared with dry condition and from 1.7 times to 1.9 times compared with saturated condition,and the strength increased by more than elastic modulus.Ductility coefficient and energy dissipation coefficient are increased slightly.(2)With the increase of cement content,the strength increases gradually,but the peak strain decreases gradually,indicating that the brittleness increases and the ductility decreases while the strength increases.Compared with the dry and saturated test blocks with the same ratio,the peak strain of the saturated frozen test block is larger,indicating that its ductility is improved at low temperature.(3)The internal mechanism of strength and stiffness improvement after hydration freezing is that ice contributes part of strength and stiffness,which may be because water in micro-pores freezes and becomes a part of the test block,which is equivalent to improving the compactness of concrete,and the cohesion and bite force between aggregate particles are improved after water freezing.

关 键 词：自密实沙漠砂贫混凝土 力学性能 峰值应变 饱水冰冻 耗散能特征 

分 类 号：TU528.53[建筑科学—建筑技术科学]