Study On Shrinkage Of Fly Ash Ceramsite Concrete

Lightweight aggregate concrete is a new type of engineering material in concrete,and is second only to ordinary concrete in China.It is helpful to make a large number of ordinary concrete instead of ordinary concrete through the further research and development of lightweight aggregate concrete.Fly ash ceramsite concrete is a kind of concrete which is made of ceramsite instead of traditional crushed stone and added with a certain proportion of fly ash.Because of its low apparent density,it is regarded as lightweight aggregate concrete.Lightweight aggregate concrete elastic modulus of coarse aggregate is low,the porosity is larger and the used amount of cement per cubic meter than ordinary concrete,these features will lead to shrinkage of lightweight aggregate concrete is too large,easy to crack.So in order to better use of lightweight aggregate concrete,we must study its contractile properties.In this paper,the shrinkage performance of fly ash ceramsite concrete is analyzed by means of experimental research,theoretical analysis and engineering experience.In this paper,the raw material requirements and technical indexes of fly ash ceramsite concrete are selected,and the mixing test is carried out.The correct feeding mode is selected,and the optimum mixing and vibration time range is determined.Based on the calculation of the mix proportion,the flexural strength test was carried out by orthogonal test.After the analysis of the results,the mechanical properties and workability of the experimental groups were basically satisfied,therefore the use of the same orthogonal table and mechanical properties of dry,temperature shrinkage test,study the water cement ratio,fly ash ceramsite,dosage of three different influence of mix design parameters on the drying shrinkage and temperature shrinkage characteristics and significance,the purpose of this paper is to explore the effect of mix proportion on the shrinkage of fly ash ceramsite concrete,and to find the best mix ratio of mechanical properties,working performance and shrinkage characteristics,so as to guide the practical construction in the future.The shrinkage stress and temperature shrinkage stress of concrete are analyzed theoretically.Also through theoretical analysis,calculation formulae of critical pavement plate length,the pavement transverse seam cut spacing between joints,starting from the perspective of experience,the distance between fly ash ceramsite concrete pavement longitudinal seam and cut the best time seam and reasonable kerf depth,for future reference.The experimental results show that the dry shrinkage of fly ash concrete,The matching parameter which has the greatest influence on the drying shrinkage is the water to binder ratio,and it increases with the increase of the water binder ratio,and the matching parameter to the temperature shrinkage is the amount of ceramsite.Based on the mechanical properties,workability,dry and temperature shrinkage characteristics,the optimum proportion of fly ash ceramsite concrete was obtained.Based on the theoretical analysis,combined with the engineering experience,the fly ash ceramsite concrete pavement longitudinal joints are generally in accordance with the width of the lane to set,transverse spacing for 4.61~7.38 m suggest that the cutting depth can be used to our specification of relative kerf depth.