The Effect of High Volume Phosphorus Slag in Cementitious Material on Hydration and Mechanical Behavior of Concrete

Abstract

This dissertation will start with the activation of phosphorous slag, and study the change rule of mechanical properties of PHS cementitious materials under the combined action of physical and chemical excitation. At the same time, the change of hydration property is studied while the mechanical property of PHS is improved. The purpose is to stimulate the activity of phosphorous slag cement base material and improve its mechanical property as much as possible under the premise of retaining its low hydration thermal property. This dissertation mainly has the following four research objectives.(1) PHS contains elements such as phosphorus and fluorine, which can effectively reduce the hydration heat generated by the hydration reaction. (2) Methods to activate PHS were studied. In this dissertation, the effects of mechanical excitation and chemical excitation on PHS activation were respectively verified. (3) Study on the optimum ratio (more than 30 percent) of PHS cement-based material, try to find the PHS-cement ratio which has great mechanical and hydration property. (4) Simulate PHS materials performance in actual mass concrete projects. After a series of studies, the result show the with decreasing of fineness, the activity of PHS would increase, and with the increase of the content of PHS, the amount of PHS involved in the reaction was higher. Using the CCS as an activator exhibits obvious alkali activate effect for both raw PHS and the ultra-fine PHS particles. Come to a conclusion, PHS slurry is a good-quality cementitious material, which (especially after effective pre-treatment) is suitable for the preparation of admixture cement mortars even at higher PHS contents. At the same time, both PHS and CCS are industrial wastes. Using PHS to make cement-based materials not only can greatly reduce production costs, but also avoid environmental pollution caused by industrial wastes. High volume PHS cement-based material is a kind of environment-friendly material also with good mechanical and thermodynamic properties.

This dissertation will start with the activation of phosphorous slag, and study the change rule of mechanical properties of PHS cementitious materials under the combined action of physical and chemical excitation. At the same time, the change of hydration property is studied while the mechanical property of PHS is improved. The purpose is to stimulate the activity of phosphorous slag cement base material and improve its mechanical property as much as possible under the premise of retaining its low hydration thermal property. This dissertation mainly has the following four research objectives.(1) PHS contains elements such as phosphorus and fluorine, which can effectively reduce the hydration heat generated by the hydration reaction. (2) Methods to activate PHS were studied. In this dissertation, the effects of mechanical excitation and chemical excitation on PHS activation were respectively verified. (3) Study on the optimum ratio (more than 30 percent) of PHS cement-based material, try to find the PHS-cement ratio which has great mechanical and hydration property. (4) Simulate PHS materials performance in actual mass concrete projects. After a series of studies, the result show the with decreasing of fineness, the activity of PHS would increase, and with the increase of the content of PHS, the amount of PHS involved in the reaction was higher. Using the CCS as an activator exhibits obvious alkali activate effect for both raw PHS and the ultra-fine PHS particles. Come to a conclusion, PHS slurry is a good-quality cementitious material, which (especially after effective pre-treatment) is suitable for the preparation of admixture cement mortars even at higher PHS contents. At the same time, both PHS and CCS are industrial wastes. Using PHS to make cement-based materials not only can greatly reduce production costs, but also avoid environmental pollution caused by industrial wastes. High volume PHS cement-based material is a kind of environment-friendly material also with good mechanical and thermodynamic properties.