渗透渗出结晶资料(国外英文资料).docVIP

渗透结晶材料(国外英文资料) Business news on the 15th of April A porous concrete structure Concrete is a homogeneous structure, in pouring concrete, control the water cement ratio of 0.23 ~ 0.25 can meet the needs of the cement hydration reaction, but such a small ratio of water to make concrete highly illiquid, casting is very difficult or even impossible, to meet the requirements of construction, people often think of control the water cement ratio of 0.4 ~ 0.8. Concrete solidification process, the excess moisture to evaporate, formed in the concrete innumerable capillary channel and minor cracks, concrete is about 8% volume before and after solidification. In addition, the concrete also creates new cracks in the process. So, concrete is a porous structure. Porosity can be harmful to concrete, mainly due to (1) leaking of reinforced concrete structures. (2) causing the concrete to suffer from frostbite; (3) chemical destruction of concrete by water carrying harmful substances Cl and SO42, etc. The C02 in the air is carbonizing the concrete. The harm seriously affected the use function and service life of concrete, so people always want to is highly compacted concrete seamless structure, instead, Chinas famous concrete crack control expert Wang Tiemeng after decades of research, draw the conclusion: the perfect is just peoples pursuit of ideal and distant, in the real world is day garment seam. We can never be overcome cracks, impossible to eliminate cracks, impossible to eliminate cracks, can only control the cracks, allows harmless crack exists, asked not to appear and appear less harmful cracks. From another Angle, crack is not only the defects, it is also the physical and mechanical properties of concrete. How big a crack is a harmful crack? American scholar Mehta believes that the pore size that affects concrete strength and permeability is not less than 100 nanometers; According to the influence of pore on the effect of the concrete, the members of wu zhongwei are divide