Preparation Of High-strength Composite Ceramsite And Chloride Permeability Of Lightweight Aggregate Concrete

China is one of the countries who have the biggest product of fly ash. Although we carried out a number of developments and research on the comprehensive utilization of fly ash in recent years, the efficiency is not high, especially the utilization of low-grade fly ash. Meanwhile, the amount of glass and its products is increasing year by year, so it is inevitable that a large number of waste glass is generated and the load on the environment is bigger and bigger. Therefore, scientific and rational utilization of solid wastes such as fly ash and waste glass has a very important significance on the improvement of the economic benefits of the related industries and the protection of the natural environment.The high strength composite ceramsite was prepared by using fly ash and waste glass as the main raw materials and some admixtures such as binder and bubble forming agent. The best composition of the ceramsite and the best burning craft parameters had been confirmed through the basic experiment and orthorhombic experiment, namely, fly ash:waste glass: binder:bubble forming agent=56:24:8:12, dry temperature:110℃for24h; preheat temperature:600℃for20min; It is1140℃to burning temperature for30min.A comprehensive analysis of impact of raw materials, additives and burning craft parameters on performance of high-strength composite ceramsite and porosity formation mechanism had been carried out. Through the XRD and SEM analysis, it was showed that a large number of amorphous gel phases which affect the strength of ceramsite were produced in the process of roasting fly ash and waste glass and abundant even bubbles were formed in the ceramsite.The lightweight aggregate concrete which used the home-made high strength composite ceramsite was designed by absolute volume. When the water-cement ratio and the sand rate were0.4, the28d compressive strength of the concrete was47.5Mpa with the dry apparent density of1878kg/m3The concrete reaches the requirement of C40concrete.Anti-chloride penetrative properties of the lightweight aggregate concrete were studied by RCM and ASTM C1202, the comparative tests were carried out with the same intensity level of the ordinary concrete, and studied the influence of aggregate, pre-wet and admixture on the chloride ion penetration of lightweight aggregate concrete. The tests showed that the permeability coefficient and the electric flux of lightweight aggregate were less than the ordinary concrete; adding a certain amount of fly ash in the process of the preparation of lightweight aggregate concrete could effectively improve its impermeability; pre-wetted the ceramsite would have adverse effects on the impermeability of lightweight aggregate concrete.