Study On Preparation And Properties Of Slag Geopolymer Pervious Concrete

To deal with the shortage of groundwater resources and waterlogging in urban areas,the national authority has proposed Construction of Sponge City as a significant initiative.Pervious concrete is the important material for the construction of Sponge City,and has great significances.With regard to the difficult coordination between permeation coefficient and strength of pervious concrete,in this paper,slag geopolymer with early strength and high strength were utilized to replace cement to produce high-performance pervious concrete.Orthogonal experiment was utilized to analyze the significance level of three preparation parameters(i.e.bone glue ratio,liquid glue ratio and briquetting pressure)upon the strength and permeation coefficient of pervious concrete.Single factor experiment was conducted to study the patterns of bone glue ratio,aggregate size,methods of maintenance and period of maintenance influencing the performance of pervious concrete.The anti-frost property was utilized to evaluate the endurance quality of pervious concrete.The major results of research are listed as follows:(1)The effect of liquid glue ratio,bone glue ratio and briquetting pressure on the properties of pervious concrete was analyzed by orthogonal design and single factor variable test.The results show that liquid glue ratio,bone glue ratio and briquetting pressure on the strength of the pervious concrete and permeability coefficient has an important impact,the results of orthogonal test show that: the bone glue ratio is the most significant factor affecting the performance of pervious concrete,followed by liquid glue ratio,briquetting pressure;When the bone glue ratio is 4: 1 to 7: 1,the bone glue ratio increases,the porosity and permeability coefficient increase,and the compressive strength decreases;When the liquid glue ratio is 0.35 ~ 0.50,the porosity and permeability coefficient decreases and thecompressive strength increases first and then decreases;When the forming pressure is 1.0 ~3.5 MPa,the compressive strength increases with the increase of the briquetting pressure,the porosity and the permeability coefficient.(2)Aggregate particle size determines the degree of tight accumulation of pervious concrete hardened bodies,the results show that: Three kinds of aggregates with particle sizes ranging from 3.0 to 5.0 mm,5.0 to 9.5 mm and 9.5 to 16.0 mm,with the increase of aggregate size,the degree of accumulation of pervious concrete decreases,the porosity and permeability coefficient increase gradually,compressive strength increase first and then decrease,the pervious concrete prepared with 5.0 ~ 9.5 mm aggregate is in good condition and the bonding state between the aggregate particles is the best,and the compressive strength is the highest.(3)The effect of curing mode and curing time on the properties of slag geopolymer pervious concrete and cement pervious concrete is different.The results show that: The curing mode(Standard maintenance and Natural maintenance)and curing age of slag pervious concrete have little effect on porosity,permeability coefficient and compressive strength,and with the curing age extended to 28 d,the mechanical properties growth is not obvious;The curing mode and the curing age of cement pervious concrete have a great influence on the porosity,permeability coefficient and compressive strength of pervious concrete.In the standard maintenance mode,with the curing age extended to 28 d mechanical properties growth is obvious;Compared with cement pervious concrete,slag pervious concrete has the characteristics of early strength and high strength.(4)The frost resistance of slag geopolymer pervious concrete and cement pervious concrete was compared by fast freezing and slow freezing test.The results show that the cement pervious concrete specimen is broken after six quick freezing and thaw cycles,and the slag pervious concrete specimen has been broken after 10 quick freezing and thaw cycles;After 25 times of slow cooling cycle,The mass loss rate of slag pervious concrete is 1.82%,compressive strength loss rate of 5.06%;The quality loss rate of cement pervious concrete is1.9% and the compressive strength loss rate is 9.30%;Slag geopolymer pervious concrete has higher frost resistance than cement pervious concrete,and the slow freezing method is more suitable for evaluating the frost resistance of pervious concrete.