Silica fume

About: Silica fume is a research topic. Over the lifetime, 10177 publications have been published within this topic receiving 173857 citations.

Hygro-thermo-chemical modeling of high performance concrete. I: Theory

Abstract: This study deals with the formulation, calibration, and validation of a new hygro-thermo-chemical model for high-performance concrete (HPC) suitable for the analysis of moisture transport and heat transfer at the early age and beyond. In Part I of this study the theoretical formulation is presented and discussed in detail. Classical macroscopic mass and energy conservation laws are written by using humidity and temperature as primary variables and by taking into account explicitly various chemical reactions, such as cement hydration, silica fume reaction, and silicate polymerization. The effect of cement hydration is modeled through the classical concept of hydration degree. Silica fume reaction and silicate polymerization are modeled by introducing the degree of silica fume reaction and the concentration of silicate polymers, along with their evolution laws. The present model can simulate early age phenomena, such as self-heating and self-desiccation, with great accuracy. Numerical implementation, calibration and validation of the model by comparison with experimental test data are postponed to Part II of this study [Di Luzio G, Cusatis G. Hygro-thermo-chemical modeling of high performance concrete. II: Numerical implementation, calibration, and validation. Cem Concr Compos, in press].

The effect of fiber properties on high performance alkali-activated slag/silica fume mortars

Abstract: The effects of length and volume fraction of steel fibers on the mechanical properties and drying shrinkage behavior of steel fiber reinforced alkali-activated slag/silica fume (AASS) mortars were investigated within the scope of this research. Steel fibers with two different lengths of 6 mm and 13 mm, and four different volume fractions of 0.5%, 1.0%, 1.5% and 2.0% were used in the AASS mixtures. Also, a Portland cement (PC) based 1.5% steel fiber (13 mm length) reinforced mortar was prepared for comparison. Test results showed that mechanical performance of AASS mortars were significantly better than PC based control mortar. This superior performance of AASS mortar may be attributed to the higher bond properties between the fibers and AASS matrix compared to PC matrix. The mechanical performance of AASS improved dramatically parallel to the increment of fiber length from 6 mm to 13 mm. Also, the drying shrinkage of AASS mortars decreased with the increasing fiber dosage.