高强活性粉末混凝土尺寸效应的研究

A Study of the Size Effect of High-strength Reactive Powder Concrete

活性粉末混凝土(RPC)是一种新型高强水泥基复合材料,具有优良的力学性能和耐久性,但RPC和普通混凝土一样存在强度尺寸效应现象,且该效应直接关系到其真实强度、承载能力和结构耐久性的评定等。试验以试件尺寸作为变量,得到4组不同尺寸试件7d和28d的抗压强度值,并采用统计分析方法对RPC试件的强度尺寸效应进行研究。以边长为100mm立方体试件的抗压强度为基准,对于边长为70.7mm和40mm的立方体试件,其7d和28d的尺寸效应系数分别为0.961 3、0.953 5和0.933 5、0.935 6;对于40mm×40mm×160mm的棱柱体,其相对于边长为40mm的立方体试件28d的尺寸效应系数为0.832 4。RPC是一种相对均质的材料,加入钢纤维后,韧性增加,脆性减小。通过对比分析,其强度尺寸效应现象并没有普通混凝土那么显著。

Reactive powder concrete （RPC） is a new type of high-strength cement-based composite with excellent mechanical proper- ties and durability. But size effect phenomenon also exist in RPC, like ordinary concrete, and this effect is directly related to its true strength, carrying capacity and assessment of structural durability, etc.. In the experiment, the size of the specimen as a variable, 7 d and 28 d compressive strength value of the four groups of specimens of different sizes were obtained, and statistical analysis meth- ods were applied to study the strength of the size effect of the RPC specimen. Reference to the compressive strength of the side length of 100 mm cube specimens, for a side length of 70. 7 mm and 40 mm cube specimens,7 d and 28 d size effect coefficients were 0. 961 3,0. 953 5 and 0. 933 5,0. 935 6 respectively. For 40 min×40 mm×160 mm prism, relative to the side length 40 mm cube specimen, its size effect coefficient of 28 d was 0. 832 4. RPC is a relatively homogeneous material. After adding steel fiber in the RPC, the toughness increases, and the brittleness decreases. Through a comparative analysis, the strength size effect phenomenon of RPC is not so significant as ordinary concrete.