苏丹谢里克水电站火山灰替换粉煤灰可行性的分析与探讨

在苏丹谢里克水电站前期筹备过程中，对苏丹当地的四种天然火山灰进行了专门的室内检测试验．包括：火山灰掺量对活性指数的影响试验，火山灰抑制骨料碱活性效果试验，火山灰对胶凝材料水化热和混凝土强度的影响实验，对火山灰替换粉煤灰的可行性进行了专门的分析研究。     

Observations on the use of ground waste clay brick as a cement replacement material

The project is funded by the European Copernicus programme and involves the recycling of waste clay brick and tile material for the partial replacement of cement in mortar and concrete. The paper reports on the preliminary investigation of the effect on the strength development of concrete of partially replacing the cement with ground 'Fletton' brick and establishes that this brick does exhibit pozzolanic activity and does make a contribution to the strength development of concrete.     

Load relaxation in steel fibres embedded in cement matrices

Twenty-four hour load relaxation curves were obtained from single fibre pull-out specimens with 60 and 80% of the peak pull-out load applied as the initial load. Two fibre types, hooked and crimped, and two matrices, cement paste and microsilica cement paste, were investigated. Tests were conducted at the ages of 1, 7 and 28 d. Two test temperatures of 22°C and 100°C were chosen

Relaxation, as defined by the percent reduction in the applied initial load, was found to decrease with age and was found to increase with the applied initial load; microsilica addition resulted in a reduced relaxation. Hooked fibres were found to relax more than the crimped fibres. A high temperature of 100°C was found to significantly increase the relaxation. After 24 h of relaxation, the specimens, in general, had a poorer pull-out performance as measured by the peak pull-out load and the pull-out energy, compared to the virgin specimens.     

Studies on mechanics of development of physical and mechanical properties of high-volume fly ash-cement pastes

High-volume fly ash concrete for structural applications was developed at CANMET. In this concrete fly ash to ‘total cementitious material’ was maintained over 55%. The purpose of this work was to investigate, by the use of similar paste mixtures of the same fly ash and cement, the mechanism by which the mechanical properties were developed. Mechanical property-porosity relations, pore size distribution, permeability, degree of hydration and Ca(OH)₂ content measurements were made. It was observed that the fly ash-cememt reaction occurred relatively early at 3 to 7 days and it was concluded that the cement matrix and residual unreacted fly ash form a good mechanical bond.