In this paper, an ultrasonic shear wave reflection method was adopted to mimic the microstructural evolution of hydrating Portland cement pastes with different water/cement-ratios (0.35, 0.5 and 0.6) cured under a constant temperature of 25°C. The reflection coefficient measured with this technique was correlated to microstructural parameters of the cement pastes. The application of numerical s...

INTRODUCTION To determine and compare the pH, conductivity and calcium release of an experimental Portland cement (PE) consisting of trioxid mineral aggregate and a comercially available modified Portland cement (C.P.M.) after 1, 2, 3, 4, 8, 10, 15 and 30 days. MATERIAL AND METHODS Cements were mixed following the manufacturer's instructions, with a powder: liquid ratio of 3:1. Each cement wa...

In this study, the amount of cement used in a concrete mix is minimized to reduce the toxic effects on users by adjusting the concrete mixture contents. The reduction of cement is achieved by using various admixtures (ground granulated blast-furnace slag, flyash, ordinary Portland cement, and activated Hwangtoh powder). To apply the mix to construction, material property tests such as compressi...

The ASTM C150 standard specification for Portland cement now permits the cement to contain up to 5% of ground limestone. While these and much higher levels of limestone filler substitution have been employed in Europe and elsewhere for many years, changing the ASTM standard has been a slow process. Having computational tools to assist in better understanding the influence of limestone additions...

Exposure conditions significantly affect the resistance of cement to sulfate attack. This article investigates the effect of sulfate on electrical conductivity of ordinary Portland cement (OPC). Cement paste specimens were prepared according to water/cement (W/C) ratio equal 0.25 either free of sodium sulfate or its addition with concentrations of 5000ppm, 10000ppm and 15000ppm by weight. This ...