引用本文:苏晓栋,陈灿明,郭壮,何建新,徐静文.混凝土双轴弹模-徐变试件垫层效果试验分析[J].水利水运工程学报,2019,(3):103-111
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混凝土双轴弹模-徐变试件垫层效果试验分析
苏晓栋1,2, 陈灿明1,2, 郭壮1,2, 何建新1,2, 徐静文1,3
1.南京水利科学研究院,江苏南京;2.水利部水科学与水工程重点实验室,江苏南京;3.河海大学港口海岸与近海工程学院,江苏南京
摘要:
混凝土双轴受压弹模和徐变试验加载应力控制在相应龄期棱柱体强度的30%~40%,相比混凝土抗压强度试验,试件表面轻微不平整和倾斜以及钢承压板与试件承压面的摩阻对混凝土双轴弹模和徐变试验结果的影响更大。为减小混凝土试件承压面轻微不平整和倾斜以及钢压板与混凝土试件间的摩阻对混凝土双轴弹模和徐变试验结果的影响,提出适用于混凝土双轴弹模和徐变试验、能使混凝土试件在弹性变形阶段整体应力应变均匀性好的垫层。通过棱柱体混凝土试件单轴受压时不同材料和组合的垫层对应变偏差率、应变曲线及弹性特征影响的比较,筛选3种组合垫层进行双轴弹模验证试验。结果表明聚四氟乙烯薄膜(PTFE)夹土工布的组合垫层能在双轴受压弹模试验中有效降低试件竖向和横向应变偏差率,使混凝土试件应力分布均匀,2层1.0 mmPTFE夹1.2 mm土工布的组合垫层总体效果最好。
关键词:  混凝土  双轴徐变  组合垫层  降偏  减摩
DOI:
分类号:TU528
基金项目:南京水利科学研究院中央级公益性科研院所基本科研业务费专项资金资助(重大)项目(Y414006)
Test analysis of effects of cushion on concrete specimen’s elastic modulus and creep under biaxial compression
SU Xiaodong1,2, CHEN Canming1,2, GUO Zhuang1,2, HE Jianxin1,2, XU Jingwen1,3
1.Nanjing Hydraulic Research Institute, Nanjing;2.Key Laboratory of Water Science and Water Engineering of Ministry of Water Resources, Nanjing;3.College of Harbour, Coastal and Offshore Engineering, Hohai University, Nanjing
Abstract:
The stress of concrete in the biaxial compression elastic modulus and creep tests is controlled at 30%~40% of the prism specimen’s strength at the corresponding age. Compared with the concrete compressive strength testing, the slight unevenness and inclination on the concrete specimen surface as well as the friction between the steel load-bearing board and the concrete specimen have a greater influence on the concrete biaxial elastic modulus and creep tests. In order to reduce the above adverse effects and make the stress and strain of the concrete specimens uniform during the elastic deformation stage, proposing a suitable cushion for the concrete biaxial elastic modulus and creep tests is necessary. By comparing the effects of different materials and composite cushions on the strain deviation rates, strain curves and elastic characteristics when the prismatic concrete specimens are uniaxially compressed, three kinds of composite cushions are choosen and verified in the biaxial elastic modulus tests. The testing analysis results show that the composite cushion with PTFE and geotextile can effectively reduce the vertical and lateral strain deviation rates of the concrete specimen in the biaxial compression elastic modulus tests, uniforming the stress distribution of the concrete specimen. The overall effect of the composite cushion with two layers of 1.0 mm PTFE and 1.2 mm geotextile is optimal.
Key words:  concrete  biaxial creep  composite cushion  deviation  antifriction
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