LOW ALKALI CEMENT

摘要

One prior requirement for concrete is durability. Ensuring of such a property demands, among other things, precluding of factors entailing deterioration in the concrete mass. The presence of alkalis above a certain limit in the cement employed in preparing concrete with reactive aggregates is one of the main factors to incite unwitting defects as a result of the alkali-aggregate reactions (expansion, cracking, deformation, etc.) in concrete. To develop low alkali cement, the siliceous aluminous component in the raw mix was replaced by materials low in alkalis. So, raw mixes were prepared with the siliceous aluminous component (clay or marl) replaced by non-traditional natural raw materials (siliceous materials, bauxite) as well as industrial by-products (granulated blast furnace slag, fly ash). The paper presents a comparison between the results obtained in the laboratory investigations on the performance (grindability, clinker burnability, volatility) of raw mixes made with traditional and non-traditional raw materials as well as the properties of clinkers and cements obtained therewith.