毛细冰晶对全轻混凝土力学性能的影响探讨  

Discuss on the influence of ice crystals in capillary porosity on the mechanical properties of ALWC

作　　者：杨健辉[1,2] 文豪 蔺新艳[1,2] 袁慧童 

机构地区：[1]河南理工大学生态建筑与环境构建河南省工程实验室,河南焦作454000 [2]河南理工大学土木工程学院,河南焦作454000 [3]河南理工大学万方科技学院,河南郑州451400

出　　处：《混凝土》2017年第9期10-14,共5页Concrete

基　　金：国家自然科学基金项目(41172317)

摘　　要：为了探讨低温作用对全轻混凝土(ALWC)的力学性能影响,以LC30为例,对混凝土养护至目标龄期后,再在目标温度为-30~10℃区间内分别养护12 h,然后再分别进行抗压强度、轴心抗压强度、劈拉强度、弹性模量、应力-应变曲线测试试验,以分析混凝土的一般力学性能随温度、龄期的变化规律。结果表明,随着养护温度降低和龄期增长,混凝土各种特征强度和弹性模量均得到不同程度提高;应力-应变曲线上的峰值应力增大,但峰值应变减小;这些特征指标的变化规律均体现了混凝土更具脆性破坏的倾向。其次,给出了各种特征强度和弹性模量与养护温度和龄期之间的相互关系式。第三,集料、砂浆低温收缩和毛细冰晶充填孔隙,是低温对混凝土强度提高的作用结果。第四,低温施工时,只要保证前3 d不受冻,那么低温就不会对结构造成损伤,反而可提高结构的刚度;而且其应力-应变曲线的过镇海模型具有良好的自适应性。In order to investigate the effect of low temperature on the mechanical properties of all-lightweight concrete （ALWC）,taking LC30 for an example, a serial of tests, such as compressive strength, axial compressive strength, splitting tensile strength, elastic modulus and the stress-strain curves,were conducted under the specified test procedure.That is the ALWC specimens were cured to a certain age （ 3,7,14,28 d, respectively ） in laboratory at first,then put to a low temperature testing box to cure 12 h again, and the target temperature is -30, -20,- 10,0,10℃,respectively.Which aims to analyze the change rules of the general mechanical properties of ALWC with the changes of temperatures and ages.The results show that all kinds of characteristic strengths, elastic modulus and peak stresses are improved with the decrease of curing temperature and the increase of curing ages,but the peak strains is reduced.Which reflects the tendency to brittle failure for ALWC.Secondly,the relationships among various characteristic strengths and elastic modulus and curing temperatures and ages are given, respectively. Thirdly, the results of ALWC strength improved depend on the shrinkage of the aggregates and mortar, and the ice crystals in capillary porosity. Fourthly, low temperature cannot lead to structure damage,in contrast, the structural stiffness can be enhanced if the ALWC is cured from the cold for three days when building in low temperature And the stress-strain curve ofGuo Zhenhai model has remarkable self- adaptability.

关 键 词：全轻混凝土 页岩陶粒 低温 强度 应力-应变曲线 

分 类 号：TU528.01[建筑科学—建筑技术科学]