基于改进的半经验超高性能混凝土配合比设计方法研究

Ultra-high Performance Concrete Proportioning Design Based on Improved Semi-empirical Method

超高性能混凝土(UHPC)优异的耐久性及力学性能受到了国内外学者的广泛关注,但目前暂无UHPC配合比的相关标准设计规范。本文使用半经验方法,采用数学软件Matlab拟合复合胶凝材料的28 d抗压强度与各胶凝材料掺量之间的关系,得出公式f_(c)=(1-0.5547X-0.9489Y+0.0941Z)·1.4089·f_(ce);拟合水胶比、复合胶凝材料、UHPC之间的关系,得出公式f_(cu)=0.3487f_(c)(B/W-0.1142);拟合钢纤维掺量与UHPC的28 d抗压强度之间的关系,得出公式f-f_(cu)=1430.4395k;最后根据紧密堆积理论确定骨料的粒径及掺量。通过以上拟合出的公式,在已知水胶比、钢纤维掺量、各胶凝材料掺量的条件下,可预测出UHPC的28 d抗压强度。验证结果表明:拟合后得出的公式准确性高,其预测结果与UHPC的实际抗压强度误差较小,可为今后UHPC的配合比设计提供依据。

The excellent durability and mechanical properties of ultra-high performance concrete(UHPC) have been widely concerned by scholars at home and abroad,but there is no relevant standard design specification for UHPC mix proportion at present.In this paper,the semi-empirical method is used to fit the relationship between the 28 days compressive strength of composite cementitious materials and the dosage of each cementitious material by using the mathematical software Matlab,the formula is derived,f_(c)=(1-0.5547X-0.9489Y+0.0941Z)·1.4089·f_(ce).The relationship between water-binder ratio,composite cementitious materials and UHPC is fitted,and the formula is derived,f_(cu)=0.3487f_(c)(B/W-0.1142).The relationship between the 28 days compressive strength of UHPC and the dosage of steel fibers is fitted,and the formula is derived,f-f_(cu)=1430.4395k.Finally,the particle size and dosage of aggregate are determined according to the dense packing theory.Through the above fitted formula,under the known conditions of water-binder ratio,steel fiber content and cementitious materials content,the 28 days compressive strength of UHPC can be predicted.After verification,the results show that the formula obtained by fitting has high accuracy,and the predicted results have small errors compared with the actual compressive strength of UHPC,providing a basis for the design of UHPC mix proportion in the future.