超高泵送自密实混凝土早龄期力学性能试验研究  

EXPERIMENTAL RESEARCH ON EARLY-AGE MECHANICAL PROPERTIES OF ULTRA-HIGH PUMPING SELF-COMPACTING CONCRETE

作　　者：陈宗平[1,2] 周济 唐际宇[1,3] 陈宇良 CHEN Zongping;ZHOU Ji;TANG Jiyu;CHEN Yuliang(College of Civil Engineering and Architecture,Guangxi University,Nanning 530004,China;Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education,Guangxi University,Nanning 530004,China;Guangxi Branch,China Construction Eighth Engineering Division.Corp.,Ltd.,Nanning 530004,China;College of Civil Engineering and Architecture,Guangxi University of Science and Technology,Liuzhou 545006,China)

机构地区：[1]广西大学土木建筑工程学院,南宁530004 [2]广西大学工程防灾与结构安全教育部重点实验室,南宁530004 [3]中建八局广西分公司,南宁530004 [4]广西科技大学土木建筑工程学院,广西柳州545006

出　　处：《工业建筑》2020年第6期111-116,38,共7页Industrial Construction

基　　金：国家自然科学基金项目(51268004);广西自然科学基金重点项目(2016GXNSFDA380032);八桂学者专项经费资助项目([2019]79号)。

摘　　要：超高泵送自密实混凝土的早龄期力学性能对超高建筑施工方案的制定具有极为重要的影响,是超高建筑施工力学的基础关键问题。针对某超400 m高层建筑的超高泵送自密实混凝土,同批次制作了30个150 mm×300 mm的标准圆柱体试件,对其进行早龄期力学性能试验,观察其受力破坏过程及破坏形态,获取轴向荷载-位移曲线,抗压强度以及弹性模量等力学性能指标;通过分析其各性能指标随龄期增长的变化规律,提出早龄期超高泵送自密实混凝土的强度及弹性模量计算式以及单轴本构方程。结果表明:超高泵送自密实混凝土具有良好的整体性;随着龄期的增长,轴压荷载-位移曲线的下降段越来越陡,说明混凝土的脆性增加;轴压强度和弹性模量随龄期变化趋势类似,龄期不大于21 d时,弹性模量的增长速率大于抗压强度的增长,当龄期在21~56 d时,弹性模量的增长速率小于抗压强度的增长,按照提出的早龄期力学性能算式得出的计算值与实测值较接近;当龄期不大于14 d时,混凝土的变形能力衰减较快,当龄期大于14 d时,变形能力变化不大;拟合出的单轴本构方程曲线与实测曲线吻合较好。The early-age mechanical properties of ultra-high pumping self-compacting concrete(SCC)have an extremely important impact on the formulation of construction scheme of ultra-high buildings,and are the basic key problems of construction mechanics of ultra-high buildings.Thirty standard cylindrical specimens of 150 mm×300 mm were produced in the same batch for ultra-high pumping SCC used in a 400-meter high-rise building.The mechanical properties of the specimens at early age were tested,the failure process and failure modes of the specimens were observed,and the axial load-displacement curve,compressive strength and elastic modulus were obtained.The variation of various performance indexes with age was analyzed.The formulas for calculating the strength and elastic modulus of ultra-high pumping SCC at early age and the stress-strain constitutive equation were presented.The results showed that the ultra-high pumping SCC had good integrity.With the increase of age,the falling section of the axial load-displacement curve became more and more steep,indicating that the brittleness of concrete increased.The change trends of the axial compressive strength and elastic modulus with age were similar,when the age was not longer than 21 d,the growth rate of elastic modulus was greater than that of compressive strength,when the age was at 21 d to 56 d,the growth rate of elastic modulus was less than that of compressive strength,and the calculated value was close to the measured value according to the formula of mechanical properties at early age proposed in the paper.When the age was not longer than14 d,the deformation capacity of the concrete attenvated faster,and when the age was longer than 14 d,the deformation capacity changed little.The curves of the variable constitutive equation agreed well with the measured ones.

关 键 词：超高泵送 自密实混凝土 早龄期 力学性能 本构方程 

分 类 号：TU528[建筑科学—建筑技术科学]