Study On Preparation And Performance Of Bio-superplasticizer

Biological refining is a new industrial production mode which parallels to the oil refining, and it is the conversion of biomass materials, such as wood fiber, agricultural waste and plant-based starch and other renewable into products including various of chemicals, fuels and bio-based materials. In this way for development of modern energy and environmental protection has found a new way out. Major domestic and foreign companies are gradually to a biological refining industry development. Our country mainly uses corn and accessories as raw material to develop the biological refining industry. Among them, bio-chemical polyols is the emerging field and the focus of attention of bio-refining industry. But corn polyols residue (CPR) restricts industry development during the corn bio-chemical polyols. Within the framework of the decrease water action theory of water-reducer, kinds of novel bio-superplasticizer were prepared in present paper from the view of CPR resource utilization and environmental protection. The optimum conditions of these products and their performance of application were investigated systemically.The results of preparation of bio-superplasticizer show that:Three kinds of bio-superplasticizer were prepared (superplasticizer based cornstarch, superplasticizer based polysaccharide and corn polyols residue based plasticizer (CPRP)), determined the optimum process parameters, respectively. The fluidity of cement paste adding three kinds of bio-superplasticizer are246.5,218.5and225.5mm (Benchmark for180±0.5mm), respectively. According to GB requirements of superplasticizer (≥20%), CPRP can instead of superplasticizer based cornstarch, and use for cement additives.The application performance of CPRP in the cement slurry was investigated. The results show that the plasicizing ability of superplasticizer with CPRP in cement paste is better, optimum dosage is0.8%, decrease water rate reached24.2%, and keep good dispersion ability. Initial and final set time of cement by adding CPRP than the blank cement extended89min and99min, respectively. CPRP produces slow coagulation effect to cement. The early strength of hardened cement by adding CPRP was reduced, but it does not affect the development of the compressive strength,28days compressive strength achieved42.7MPa (42.7/123).In order to discuss the water-reducing mechanism of CPRP, the effects of cement slurry rheological behavior, dispersion of cement particles and cement hydration process were investigated after adding water-reducing agent. The results show that the more limit adsorption quantity of CPRP on the surface of cement particles, the greater fluidity of cement paste, the slower the settlement; and the higher cement particle size distribution frequency, the better dispersion performance of CPRP. The early hydration process of cement was slowed by adding CPRP, but promoted the late hydration process of cement. The early cement slurry by adding CPRP form a huge AFt crystal and fill cement particle pore, make later hydration more fully, improving the mechanical properties and durability of hardened cement. On the basis, the water-reducing mechanism of CPRP was put forward that the hydrogen bonding interaction, hydration film lubrication and electrostatic repulsion. Applied CPRP to mortar, the measured saturation dosage is0.8%, and decrease water rate can amount to22.5%. Under the saturation dosage, the mortar compressive flexural strength is the best.Based on the corn polyols residue as raw material, this paper studied on CPRP preparation and discussed the application performance. It provides theoretical basis for CPR resource utilization, and promotes the overall level of biological refining industry, broaden sources of the raw materials in water-reducing industry. It has a good application value to save resources and protect the environment.