超高强混凝土RPC强度的尺寸效应

Size Effect on Strength of Ultra-high Strength Concrete RPC

活性粉末混凝土(RPC)是一种新型超高强水泥浆复合材料,具有优异的力学性能和耐久性。为了能够更好地应用于结构工程,对超高强混凝土RPC试件强度的尺寸效应进行试验研究和机理分析。研究结果表明:以4cm立方体试件抗压强度为基准,对于10cm立方体试件,150MPa级和200MPa级的尺寸换算系数分别为0.81和0.76;对于10cm×10cm×30cm棱柱体,150MPa级和200MPa级的尺寸换算系数分别为0.71和0.63;随着基准抗压强度的增大,尺寸效应换算系数有减小的趋势,即大尺寸试件的抗压强度较小。RPC是一种典型的弹脆性材料。材料开裂后裂纹很快失稳扩展,损伤集中在局部区域,因而尺寸效应更明显。

Reactive Powder Concrete（RPC）is a new kind of ultra-high strength cement based compo-site with excellent mechanics performance and durability.In order to make RPC used in structural enginee-ring effectively,size effect on strength of the ultra high strength concrete RPC specimen is experimental studied and the mechanism is analyzed in this paper.Test results show that if the 4 cm cube compressive strength is the control strength,conversion coefficients of 10 cm cube compressive strength at 150 MPa and 200 MPa grade are 0.81 and 0.76 respectively;conversion coefficients of 10 cm×10 cm×30 cm prism compressive strength at 150 MPa and 200 MPa grade are 0.71 and 0.63 respectively;the size effect conversion coefficient tends to decrease with the increase of control strength,the larger the specimen size,the lower the compressive strength.RPC is a typical brittle material.It extends instability quickly after cracking;damage concentrated in the local area,and therefore appears higher size effect.