Effect of surface treatment on carbonation of concrete -- the influence of water binder ratio

    After silane penetration coating surface treatment, the concrete still has good air permeability, concrete internal moisture can be evaporated from the surface, it will not affect the diffusion and migration of CO2 to the concrete interior. Figure 5.4 for the water content of up to 9% of the cement mortar test block with silane surface treatment, dry conditions in the natural environment. After 3D, the residual moisture content is 3%~4%, the evaporation rate of water is close to that of common cement test block, which shows that the surface treatment does not affect the moisture content of the concrete, that is, it will not affect the permeability of the concrete. In view of this, permeable coating surface treatment of concrete while reducing the gross of water, but the permeability and no change, after surface treatment of concrete of with and without surface treatment of concrete carbonization performance should be basically the same.

    By silane siloxane surface treated concrete accelerated carbonation test and 16 weeks after determination of carbonation and found that the surface treatment of concrete carbonation depth decreased slightly, and the increased with the amount of paint, the carbonation depth has further reduced the trend, and in the permeable coated material under the same volume, concrete water cement ratio is smaller, the depth of carbonation smaller, as shown in Figure 5.5, water binder ratio is still decided to main factor the carbonation resistance of concrete surface treatment, 5.5. Water binder ratio is still decided to main factor the carbonation resistance of concrete after surface treatment, the numbers in Figure 5.5 said concrete using different quantity of paint surface treatment after carbonation depth accounted for untreated percentage of concrete carbonation depth.

     It is required that the rapid test result is obtained under the condition that the relative humidity is 60%. If dye environment is very dry, without surface treatment of concrete dehydrate faster and the surface treatment of concrete due to the slow dehydration but will accelerate the carbonation process, resulting in greater carbonation depth.