Properties of Silica-Fume Concrete. Repair, Evaluation, Maintenance, andRehabilitation Research Program

摘要

This study was conducted to determine those properties of silica-fume concretewhich might affect cracking and to develop guidance for minimizing cracking problems associated with the use of such concrete in future repair projects. Tests included compressive and tensile splitting strengths, modulus of elasticity, Poisson's ratio, ultimate strain capacity. uniaxial creep, shrinkage, coefficient of thermal expansion, adiabatic temperature rise, and abrasion erosion. None of the material properties of silica-fume concrete studied with the possible exception of autogenous shrinkage, indicate that this material should be significantly more susceptible to cracking as a result of restrained contraction than conventional concrete. In fact, some material properties, particularly ultimate tensile strain capacity, would indicate that silica-fume concrete should have reduced potential for cracking. While silica fume offers potential for improving many properties of concrete, the very high compressive strength and resulting increase in abrasion-erosion resistance are particularly beneficial in repair of hydraulic structures. These concretes should be considered in repair of abrasion-erosion susceptible locations, particularly in those areas where locally available aggregate might otherwise not be acceptable. The potential for cracking of restrained concrete overlays, with or without silica fume, should be recognized. Any variations in concrete materials, mixture proportions, and construction practices that will minimize shrinkage or reduce concrete temperature differentials should be considered.