Research On Poly-carboxylic Super-plasticizer's Application In Guizhou Region

Guizhou, being located remote, is relatively poorer than other areas in the constituent materials of concrete: the cement product quality control is laggard compared with the developed eastern regions; the fine aggregate is almost mountain sand which has poorer particle shape and grading and its content of clay and powder weighs heavier. Therefore, the limitations exist in concrete preparation, which leads to poor workability and a great slump loss. However, it has been internationally acknowledged that the poly-carboxylic super-plasticizer is a kind of new green environment-friendly water-reducing admixture which provides lower mix proportion, higher water-reducing rate, better scattered maintaining performance, less slump loss and more comprehensive cement adjustability, which illustrates a favorable research and application prospects. Currently, the poly-carboxylic super-plasticizer has still not been popularly applied in Guizhou district and this paper has taken the lead in doing research on the adaptability between the poly-carboxylic super-plasticizer and local materials in Guizhou and the region's concrete mix proportion design.Firstly, through the cement paste and mortar experiment, the adjustability between poly-carboxylic super-plasticizer and local materials in Guizhou is studied in this thesis, the results of which suggest that poly-carboxylic super-plasticizer can achieve the goals of low mixing proportion, high water-reducing rate and wide adjustability with the Guizhou local binding materials. It has effectively solved the problem of bad fluidity in mixing mortar and concrete caused by the higher content of clay and powder in mountain sand. Secondly, in this thesis through the orthogonal experiments the mix proportion for the concrete applying poly-carboxylic super-plasticizer in Guizhou region is redesigned and the results has demonstrated that the application of poly-carboxylic super-plasticizer has decreased the dosage of both cement and water and the initial and final strength will increase with the additives increasing. Furthermore, a contrast with the concrete using the naphthalene super-plasticizer has also been carried on in this thesis and it has proved the fact that concrete mixed with poly-carboxylic super-plasticizer relatively prevails in both fresh concrete performance like workability, slump maintenance, compressive bleeding rate, air content, etc. and hardened concrete's properties such as strength, permeability, freezing resistance and so on. On the basis of the former study, this thesis has worked on the preparation of High Performance Concrete with poly-carboxylic super-plasticizer in Guizhou region: in the cases of low water-gel ratio and slag powder as additives, the HPC can achieve the required strength and what is more important is that the problem of higher viscidity in HPC preparation caused by adding silica fume has been successfully solved, which has provide guidance for the preparation of HPC in Guizhou region.