Experimental Study On Bond Property Between High Volume Fly Ash Concrete And Steel Bars

Fly ash is by-product of coal-fired power plants from combustion of fuel, and it is one of the larger emissions of industrial waste residue in china. Practice has proved that the rational use of fly ash resource in the concrete structures, both significantly improve part of the performance of the concrete, mechanical properties and durability, but also reduce environmental pollution, reduce the amount of cement, save resources and it has a very important practical significance of weakening the current energy crisis, but also conforms to the concept of the development of high performance green concrete. Currently, fly ash has become a most widely used substitute products of cement in concrete structural engineering around the world.In recent years, the application of fly ash in concrete engineering is becoming increasingly common, although many experts and scholars at home and abroad had undertaken extensive research on the performance of fly ash concrete, but the bonding properties of fly ash concrete and reinforced is eventually few, and the impaction of fly ash on the bonding properties of concrete and reinforced has not yet reached a consensus. In reinforced concrete structure, the reinforced and concrete work together, the bonding between reinforcement and concrete is the basic premise, and presently the analysis of bonding properties of fly ash concrete is still use the bonding theory of ordinary concrete and reinforced, thus, the research on bonding properties of fly ash concrete has a very important theoretical and practical significance.Based on the analysis of the results of the bonding properties of the predecessors, this paper adopts the direct pull-out empirical method to research the bonding properties of fly ash concrete and reinforced, according to the experimental data, we got the curve of bond stress-freeslip of fly ash concrete and reinforced, fitting to come to formula of the ultimate bond stress of fly ash concrete that consider the content of fly ash. Meanwhile, through comparative analysis of experimental data, we got the influence of fly ash, steel type and diameter, water-cement ratio on the bonding properties, proposed to the design method of bond anchoring of concrete and reinforced that consider the impact of fly ash. The tests shows that:with the increase of fly ash, the compressive strength of concrete reduces significantly, the ultimate bond strength of reinforced and concrete also show a downward trend, but the impact is not significant when fly ash is less; the smaller the water-cement ratio is, the better the bonding properties of the reinforced and concrete is; the with the diameter of steel increasing, the bonding properties of the reinforced and concrete is weakened.