Testing Research On Physical And Mechanical Performance Of High Fly Ash Content Concrete

As a kind of industrial by-product, the emission of fly ash is so great in china, high fly ash content concrete as a "green" building materials can consume plenty of fly ash, not only reduce cement dosages and the production of concrete, but also reduce environmental pollution and save the cultivated land. But with the increase of the number of fly ash, some performance of high fly ash content concrete get bigger weakened, such as the early strength of concrete lowed obviously, limiting the application scope of high fly ash content concrete. It is the main reason that the potential activity of fly ash has not been fully excitation. In this paper, the experimental study and theoretical analysis on the performances of high fly ash content concrete under flexural, discount compressive, setting time, hydration heat and crack resistance are carried on. The main results are as follows:1.The effect of the number of fly ash, the active agent and water-cement ratio on flexural properties of fly ash concrete are researched through549fly ash concrete specimens of100mm×100mm×400mm. The more reasonable of the number of fly ash(30%-40%), the active agent(1%～1.5%) and water-cement ratio of fly ash concrete are put forward respectively.2. The effect of the number of fly ash on the air content of fly ash concrete, the effect of the air content on flexural properties is researched through the experiments of the air content, flexural strength and compressive strength of fly ash concrete on21. The experiment results showed, the air content of fly ash concrete can be lowed effectively by fly ash, the lower of the air content can improve the mechanical properties of concrete.3. The effect of the number of fly ash, the active agent on the setting time of fly ash concrete are researched through the experiment of the setting time of fly ash concrete which is on the different number of fly ash and the active agent on13. The experiment results showed, the setting time of concrete can be postponed by fly ash and the effect of the active agent is contrast.4. The effect of the number of fly ash, the active agent on hydration heat of fly ash concrete are researched through the experiment of fly ash cement hydration heat on10. The experiment results showed that fly ash can reduce the hydration heat of concrete and the effect of the active agent on hydration heat of fly ash concrete is not big when the number of the active agent is lower(1%～1.5%).5. The effect of the number of fly ash, the active agent on the property of fly ash concrete anti-cracking are researched through observed the crack characteristic of10plate specimens of fly ash concrete with the size of600mm×600mm×40mm. The experiment results showed that fly ash can improve the property of concrete anti-cracking and the effect of the active agent on the property of fly ash concrete anti-cracking is not big when the number of the active agent is lower(1%～1.5%).