Size effect on flexural, splitting tensile, and torsional strengths of high-strength concrete

Abstract

This paper presents the results of an investigation into the size effect on flexural, splitting tensile, and torsional strengths of high-strength concrete (HSC) with normal aggregate (crushed limestone) and lightweight aggregate (sintered fly ash). The Bazant’s size effect law gives a very good fit to the flexural strengths of both normal and lightweight aggregate HSC measured from beams of different sizes. As observed in the size effect curve, the fracture behavior of the lightweight HSC seems more brittle than that of the normal HSC. Linear elastic fracture mechanics may still be less applicable to HSC in the normal size range than nonlinear fracture mechanics. A reverse size effect is observed in the prism splitting tensile strengths of both normal and lightweight HSC and possible mechanisms of the reverse size effect are discussed. The torsional strength of the lightweight HSC appears to have a stronger size dependency than that of the normal HSC.