Study On Drying Shrinkage Of High Volume Fly Ash Concrete

With the growing environmental consciousness of all humanity, higher requirements are proposed to economy, ecology and environmental benefits of concrete in modern engineering.As a new green high-performance building material growing into maturity in this particular historical circumstances, High Volume Fly Ash Concrete wins the favor of more and more scholars and engineers, because of its economy and environmental benefits. Therefore, this paper introduces a lot of experimental research work about dry shrinkage of High Volume Fly Ash Concrete, as well; this papar also analyzes the nonlinearity of dry shrinkage and compressive strength. The following works have been accomplished in this paper:(1)By the dry shrinkage test of High Volume Fly Ash Concrete in different water-cement ratio, quantity of fly ash, age and the mixing amount of additive, the impacts of these factors on dry shrinkage have been studied.The experimental results are followed: Dry shrinkage rate increased sharply in the ealier stage, but the growth slowed in the later stage, to the 60 days dry shrinkage rate no longer developed obviously; keeping the quantity of fly ash equal, Lower water-cement ratio can reduce the shrinkage rate of concrete; the quantity of fly ash produced many apparent negative effects on dry shrinkage rate, the dry shrinkage rate of fly ash concrete were obviously less than reference concrete, and dry shrinkage rate increasesd with reducing the quantity of fly ash; keeping the water-cement ratio equal, the shrinkage rate reduced with increasing the quantity of fly ash.(2) By the compressive strength test of High Volume Fly Ash Concrete with the size of 150mm×150mm×150mm, the impacts of age, quantity of fly ash, water-cement ratio and additive on compressive strength have been studied.The experimental results are followed: under normal curing conditions, the intensity developed rapidly in the first few days, and then gradually slowed; keeping the quantity of fly ash equal, the intensity of concrete decreased with the increasing of water-cement ratio; keeping the water-cement ratio equal, the intensity of concrete reduced with the increasing of quantity of fly ash.(3) Fitting the dry shrinkage rate of concrete and compressive strength using Matlab softmare, model between dry shrinkage rate and age,model among dry shrinkage rate and water-cement ratio, quantity of fly ash, age, the mixing amount of additive and model between dry shrinkage rate and compressive strength were obtained.