Compressive Performance Research On High Fly Ash Content Concrete

Fly ash is coal-fired power plant produces industrial byproduct, the emission of fly ash is very enormous in our country. High fly ash content concrete (HFCC) can consume lots of fly ash, reduce cement consumption and the production cost of concrete. It also can economize the resources and in the meantime turn waste into wealth. In the mass concrete structure HFCC can effectively reduce the temperature by the cement hydration heat caused, thus HFCC can avoid the early crack of the mass concrete structure. But in the same time with increasing the number of the fly ash, the volcanic ash activity of the fly ash do not get good arousal, the make the early strength of concrete reduced considerably. It is this reason for technological personnel to fly ash concrete have certain of prejudice, limiting high fly ash concrete application.This text represents the study on the main performance of HFCC, combining practice data, and makes every to find and improve the early strength of HFCC, raising their use potentiality actually. The main achievements are as follows:1.Property of the fly ashFly ash is the main compositions of HFCC. The natures of the fly ash influence the performance of the concrete directly. Several main physical and chemical properties are introduced:the density, detailed degree, chemical element composition, activity of the fly ash, the interaction between the fly ash and concrete etc.2.The compressive strength of concrete cubeThrough the experiments of the compressive strength of concrete cube on 351 fly ash concrete with the dimensions of 100mm×100mm×100mm, concrete grade on compressive strength, the number of the fly ash, the varieties of the active agent and conserve age were investigated. The experiment results showed, the early strength can be improved after adding to active agent; With the conserve age growth, The strength development of the fly ash concrete is quicker than benchmark.3.Flexural compressive strength of the cement grinding Through the experiments of the Flexural compressive strength of the cement grinding on 113 fly ash cement grinding with the dimensions of 160mm X 40mm X 40mm, the number of the fly ash, the varieties of the active agent and conserve age were investigated. The experiment results showed, the early strength can be improved after adding to active agent; With the conserve age growth, The strength development of the specimens adding into the fly ash is quicker than benchmark.4.The air content of the fly ash concreteThrough the experiments of the air content of the fly ash concrete and the density of the mix on 18, the experiment results showed, the mixture of the fly ash have little influence with the air content of the concrete.5.The cement hydration heatThrough the experiment which is on the fly ash content was 0%,40%,50%, 60% of the cement hydration heat determination of seven days. The experiment results showed, with the fly ash content increasing, the cement hydration heat is little.