Self-compacting Fly Ash Concrete Research And Application

Self-compacting Concrete(SCC) is one of High Performance concrete(HPC) which can consolidate under its own weight with advantages: remarkably reducing the noisy pollution and the worker's labor intensity in construction;deducing the rough surface because of over-vibration or missing-vibration in the conventional construction and resolving the quality problems of hole resulting from the coarse aggregate blocking in the section of complex shapes and densely-packed reinforcement;using largely industrial solid waste such as fly ash and blast furnace slag. The development and application of SCC is useful for using the comprehensive utilization of resource and the protection of the environment.In this paper, the raw materials of self-compacting Fly Ash concretes were discussed by analyzing of rheological behavior and formulating method. The paper study the influence of the mineral admixtures such as fly ash, superplasticizer, as well as their composite on the rheological performance of concrete. Base on experiments, it is analyzed that the effect of fly ash and superplasticizer on the rheological performance of concrete. The factors leading to the incompatibility between concrete superplasticizers and cement were discussed, and some useful methods to solve these problems were put forward. In addition ,The reasons and the mechanisms of the greater slump-loss of concretes added with superplasticizers were summarized , and some valid measures which can be used to control the slump-loss of the concretes were proposed.Shrinkage is a basic characteristic of cement concrete, which is one of the main reasons caused of cracks of concrete structures and has been an unsolved technical problem. This paper has made a thorough study on its properties and delved further into its mechanism of compensation on cement concrete shrinkage by adding concrete expansive agent.By using orthogonal experimental studies on mix design of self-compacting Fly Ash concretes, in this paper, an orthogonal experimental method of five factors and four factor levels was adopted to carry out the experiments of proportioning of SCC. The influence of different experimental factors including total water/binder ratio, fly ash, superplasticizers, expansive agent and sand percentage on the strength and workability of SCC was studied, and the effect of each factor level on proportioning of SCC and the difference between factor levels were also analyzed. Liner regression was carried outwith the results and a prediction model is given. At last, according to the characteristic of self-compacting Fly Ash concretes, put forward the measure to untie quality of concrete, and the compare in technique and economy were carried.