Research On Ceramsite Aggregate's Surface Modification And Property For Concrete

Lightweight aggregate concrete has the advantages of high strength, light weight, good durability, heat preservation thermal insulation, earthquake resistance and etc, thanks to the characteristics of lightweight aggregate. Compared with traditional aggregate, lightweight aggregate is light and has internal porous unique structure. But because we started to product the lightweight aggregate quite late, our process equipments'development was lag behind, resulting in most of ceramsite is single grain, grading is not good, water absorption is heavy, density is too large, and the intensity is low relatively. At present, construction of high-rise building and large span bridge in Chongqing provides a broad development space for the application of lightweight aggregate concrete, but because of its deficiencies, the development of high-strength lightweight aggregate concrete has been a certain degree of obstruction.This paper aims to change the characteristics of ceramsite produced in Chongqing with various measures of crushing, pre-wetting, water-repellent and coating with compounded gel materials to plant high strength ceramsite concrete, and study the properties of concrete with modified ceramsite.Test results show that:â‘ The ceramsite with unsatisfactory gradation can be broken into a continuous gradation, after crushing, the ceramsite's particle size become smaller, grading change better, cylinder compressive strength increase significantly. With the same experimental conditions in other cases, use broken ceramsite replace part of complete ceramsite, the compressive strength increase with the substitution.â‘¡After pre-wetting , the ceramsite's water absorption is lower after pre-wet with 1h, hardly absorb from concrete mixture when mixing, the mixing content liquidity is better than untreated ceramsite mixture. With the degree of pre-wetting increasing, early strength of concrete decreased rapidly, but late strength gradually flat with untreated ceramsite concrete.â‘¢After hydrophobic processing, the ceramsite's water absorption reduce significantly, the effect is best when the proportion of WKT hydrophobic agent is 1:16. After treated, the mixing content liquidity is better, the initial slump is 195mm, while 160mm when the ceramsite is untreated. The slump loss is relatively small, its strength higher than untreated ceramsite concrete strength. â‘£After coating with different proportion compounded gel materials, the ceramsite's water absorption reduce significantly, the effect is best when the proportion of ceramsite quality to compounded gel materials quality is 3:2. After coating with compounded gel materials, the adhesive aggregation become better, the density increase, the compressive increase significantly, the coefficient of thermal conductivity is small, its coefficient of thermal conductivity is 0.22 w/(m.k) when the dry bulk density is 1500kg/m3, compared with ordinary concrete, its thermal conductivity is very small, and the insulation property is very good.