Experimental Study On Performance Of Sand-based Water Permeable Concrete Road Brick

This paper examines the strength and the frost-thawing resistance of sand-based permeable concrete road bricks applied a self-developed reinforcing agent,compared with three kinds of similar additives purchased on the market,aiming at the effect of considerations on permeable bricks,such as large difference of temperature from day to night during winter-spring season in the north area of China,the serious freeze-thaw action,the use of snow-melting agents and the pollution resulting from coal dust and other acidic substances.And this research focuses on the application of permeable bricks to the cold areas to enhance their strengths and ability to resist freezing-thawing.The permeable concrete road bricks,which have good water permeability,moisturizing,skid-resisting,frost-thawing resisting,environmentally sound,etc.,are a concrete product made of cement,sand,and water as the main raw materials,supplemental additives（such as reinforcing agents,binding agents,protective agents,modifiers,etc.）,after having mixed,molded and cured,and other processes.These bricks are used for paving the roads in parkway,footway and parking lots,and they allow for quick infiltration of rainwater,restoring the water storage capacity,improving the ecological environment of vegetation.The utilization of these bricks in the construction of municipal or urban engineering would reach the good economic,social and ecological benefits,while reducing the discharge of three wastes（i.e.,waste gas,waste water and waste residues）and the waste of various natural resources.For these reasons,many research works and related product development have been done by many organizations and manufacturers at home and abroad,most of research works focuses on the applications of permeable bricks to the non-freezing areas.It has shown that the compressive strength of concrete brick specimens at the 28d reaches 59.2MPa,with rupture strength of 9.3MPa,when the self-developed reinforcing agent of 5%was added to the ordinary concrete（C25）.The enhancement of concrete strength by self-developed reinforcing agent is 1.55 to 2.75 times of that by three similar additives.The consumption of self-developed reinforcing agent is only 62.5%of that of three similar additives,and its cost is 64.6⁶8.4%of that,thus reaching high economical efficiency.The compressive strength of concrete specimens at the 28d after adjusting the water-cement ratio,gradation,and ash-gather ratio,reaches to 35.6MPa,with the coefficient of water permeability being 3.5×10^-2cm/s.Also,the test results show that the road performance and durability of permeable bricks may meet or exceed the requirements of the Specifications,so the application of these bricks can be promoted in cold areas in northern China and some areas with high levels of saline soil.The innovation of this research is to analysis the mechanism of self-developed reinforcing agent and its action,as well as its good economy.