Internal curing of high-performance concrete with pre-soaked fine lightweight aggregate for prevention of autogenous shrinkage cracking
Internal curing of high-performance concrete with pre-soaked fine lightweight aggregate for prevention of autogenous shrinkage cracking
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DOI：
10.1016/j.cemconres.2008.02.001
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发表时间：
2008-06-01
影响因子：
11.4
通讯作者：
Hoogeveen, Ted
中科院分区：
文献类型：
--
作者：
Cusson, Daniel;Hoogeveen, Ted
通过对4对大尺寸棱柱形高性能混凝土试件同时进行自由收缩和约束收缩试验，研究了不同内养护水平对降低高性能混凝土自收缩裂缝的效果。内部养护由预浸细轻集料(LWA)提供，作为常规砂的部分替代。结果表明，在高性能混凝土中掺入178 kg/m(3)饱和轻骨料，提供27 kg/m(3)IC水，在不影响高性能混凝土早期强度和弹性模量的前提下，消除了由于抑制自收缩而产生的拉应力。结果表明，混凝土开裂的风险可以从最大膨胀应变之后的自由收缩应变的大小保守地估计出来，而膨胀应变可能在很小的时候就开始发展。在高水平内部养护的第一天观察到的自膨胀可以显著降低混凝土结构中的裂缝风险，因为弹性应变和蠕变应变最初都是在压缩中发展的，使得抗拉强度在稍后开始拉应力之前进一步增加。皇冠版权所有(C)2008由爱思唯尔有限公司出版。保留所有权利。
The effectiveness of internal curing (IC) to reduce autogenous shrinkage cracking in high-performance concrete (HPC) was investigated using different levels of internal curing on four pairs of large-size prismatic HPC specimens tested simultaneously under free and restrained shrinkage. Internal curing was supplied by pre-soaked fine lightweight aggregate (LWA) as a partial replacement to regular sand. It was found that the use of 178 kg/m(3) of saturated LWA in HPC, providing 27 kg/m(3) of IC water, eliminated the tensile stress due to restrained autogenous shrinkage without compromising the early-age strength and elastic modulus of HPC. It was shown that the risk of concrete cracking could be conservatively estimated from the extent of free shrinkage strain occurring after the peak expansion strain that may develop at very early ages. Autogenous expansion, observed during the first day for high levels of internal curing, can significantly reduce the risk of cracking in concrete structures, as both the elastic and creep strains develop initially in compression, enabling the tensile strength to increase further before tensile stresses start to initiate later. Crown Copyright (C) 2008 Published by Elsevier Ltd. All rights reserved.