Calcium hydroxide (CH) represents a significant volume of the products formed from the cement-water reaction. The extent to which the CH phase contributes to the engineering integrity and volume stability of cement-based binders is however moot. Evidence in support of the view that calcium hydroxide has a significant role in determining the mechanical performance and volume stability of cementi...

The influence of cement particle-size distribution on autogenous strains and stresses in cement pastes of identical waterto-cement ratios is examined for cement powders of four different finenesses. Experimental measurements include chemical shrinkage, to quantify degree of hydration; internal relative humidity development; autogenous deformation; and eigenstress development, using a novel embe...

The waste agriculture materials cause environment pollution, recycle of these materials help sustainable development. This study focused on the impact of used oil palm shell ash on the compressive and flexural strengths of cement mortar. Two different cement mortar mixes have been designed to investigate the impact of oil palm shell ash on strengths of cement mortar. Quantity of 4% oil palm she...

During the hydration of cement, tricalcium aluminate (C3A) reacts with gypsum and forms ettringite (AFt). Once all gypsum is consumed, ettringite can further react with remaining C3A and form monosulfate (AFm) at 1–2 days. Normally, at early ages, ettringite all transfers to AFm phase. After several months or years, ettringite can form again if a new source of sulfate becomes available in the p...

A quantitative comparison of real and computer-generated (model) cement paste microstructures based on the analysis of threedimensional image sets is presented. In addition to a visual presentation of extracted two-dimensional images, the comparison is based on the calculation of the normalized two-point correlation function for a variety of phases including unhydrated cement, hydration product...

This study aims to the influence of a lightly burned magnesium oxide (LBMO) expansion agent on rheological properties (the slump flow, plastic viscosity and variation shear stress) cement-based materials. Four different mass contents (i.e., 0%, 3%, 6% 9%) LBMO were selected. The following compressive strength value corresponding cement concrete tested. Cement with two grades 30 MPa 50 (C30 C50)...

Some Problems on High Strength Concrete for Prestressing by Kanji YAMAZAKI (Research Laboratory of Nihon Cement Co., Ltd., Tokyo) This paper describes some problems on high strength concrete studied in our laboratory in recent years. Summary of this report is as follows: (1) In order to make high strength concrete for prestressing, it is necessary to lower the water-cement ratio. But, in the ca...