The Chloride Permeability of Persulphated Phosphogypsum-Slag Cement Concrete

• 作 者: 黄有强 LU Jianxin CHEN Feixiang 水中和
• 机 构: State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology,China R
• 出 处: Journal of Wuhan University of Technology(Materials Science)
• 发表日期: 2016年05期
• 关键词: permeability hydration Portland penetration communicating pores hydroxide interf

The chloride permeability and microstructure of persulphated phosphogypsum-slag cement concrete(PPSCC), the Portland slag cement concrete(PSCC) and ordinary Portland cement concrete(OPCC) were investigated comparatively. Some test methods were used to evaluate the chloride permeability and explain the relationship between the permeability and microstructure of concrete. The results show that the resistance to chloride penetration in PPSCC is significantly better than that in OPCC, the reasons are as follows: 1) the slag in PPSCC is activated by clinker(alkali activation) and phosphogypsum(sulfate activation), forming more low Ca/Si C-S-H gel and gel pores below 10 nm than OPCC, improving the resistance to chloride penetration; 2) the hydration products of PPSCC have a much stronger binding capacity for chloride ions; and 3) in the same mix proportion, PPSCC has a better workability without large crystals calcium hydroxide in the hydration products, the interfacial transition zone(ITZ) is smoother and denser, which can cut off the communicating pores between the pastes and aggregates.

The chloride permeability and microstructure of persulphated phosphogypsum-slag cement concrete (PPSCC), the Portland slag cement concrete (PSCC) and ordinary Portland cement concrete (OPCC) were investigated comparatively. Some test methods were used to evaluate the chloride permeability and explain the relationship between the permeability and microstructure of concrete. The results show that the resistance to chloride penetration in PPSCC is significantly better than that in OPCC, the reasons are as follows: 1) the slag in PPSCC is activated by clinker (alkali activation) and phosphogypsum ( sulfate activation), forming more low Ca / Si CSH gel and gel pores below 10 nm than OPCC, improving the resistance to chloride penetration; 2) the hydration products of PPSCC have a much stronger binding capacity for chloride ions; and 3) in the same mix proportion, PPSCC has a better workability without large crystals calcium hydroxide in the hydration products, the interfacial transition zone (ITZ) is smoother and denser, which can cut off the communicating pores between the pastes and aggregates.