Research And Application On Low-Cost High Performance Concrete (LC-HPC)

Depending on the Tenth Five-year Plan by China, the workability, physical mechanics property, durabilities of concrete were systematic studied. Combining with micro-structure test and applying the laws between the composition, structure, qualitiy of materials and considering the production cost of engineering, the principle of the design and technique route of mamufacturing Low-Cost High Performance Concrete (LC-HPC) was put forward. The important theoretical and technological support for the design, application of LC-HPC is provided.Analyzing the factors of concrete workability, mechanics quality, durability, cost, the key of mamufacturing LC-HPC are compatible of chemical admixture, stability of volume durability are pointed out, at the same time the principle and the technique route of LC- HPC is put forward .On the base of studying the compatible of chemical admixture and mineral admixture with cement, according to heat of hydration, chemical shrinkage and environment condition in the course of concreting and restrained cracking sensitivity indicates different quantity of mineral admixtures lead to different effect to the stability of concrete, such as 30% fly ash and 40%~60% micro-slag can improve the stability, but silica fume deteriorates the stability. The one of most important factor of affecting durabilities in construction concrete is chloride deterioration. The chloride penetration current exceeds 2,000 coulomb in the no mineral admixtures silicate cement, using 30%~40% fly ash it falls to 800 coulomb and the 60% micro-slag falls to 500 coulomb; though silica fume reduces penetration current, it deteriorates the workability of concrete. At the same time fly ash and silica fume also can repress the anti-sulfate attack and the alkali-aggregate reaction; In addition, the relation between air-entraining admixture, cementitious materials quantity with Freezing-thaw property of concrete were studied; and according to the different affecting factors the durable life of concrete was estimated.The laws between the composition, structure, quality of materials of LC-HPCis studied by means of SEM, MIP, and so on testing measures. The reaction of hydration and filling effect of mineral admixture not only reduces the proportion of pore of structure and sizes and odds directional crystal of the unfavorable crystal phases such as CH but also leads to the mining of pore size, so it the effect improves the weak structure of interface transition area.Summarying ShenZhen and WuHan's concrete companies practical proportion design of concrete and analyzing relations between each composition in the LC-HPC, author puts forward to lower cost ways and applies to engineering that leads to reducing cost of production over 8?m .On the base of analyzing engineering construction in some mass concrete author first puts forward the self-catalysed effect of micro-slag and indicates the one of keys of guaranteeing the engineering quantity is the reasonable measure of heat preservation and descention.