When mixing concrete compound

Microsilica concrete repair material strength than non-mixed  with silica fume concrete repair material strength up to 20% to 30%, while the experiment is the same as water, concrete  mixing thereof, in order to obtain construction Liquidity requirements, and often need to add some water (more than the required amount of water of hydration of cement), these more water Not only the thinning slurry, cement weakened, and the excess water remaining in the concrete to form blisters Or waterways, with the concrete to harden and evaporate after  leaving pores. Precast concrete plant the actual stress of concrete surfaces Plot, but also in concrete strength, easy stress concentration  around the pores. In concrete, the internal Bleeding blocked by the aggregate particles gather in aggregate form porous interface below. In aggregate interface filter Region is formed of calcium hydroxide (CH) to more than other areas. CH crystal growth and parallel to the larger aggregates concrete mix plant orientation. Parallel to the aggregate surface cracking large CH crystals easier than calcium silicate hydrate Gel (C-S-H) weak. Cement and aggregate the interface between the porous and the filtering zone as many fixed CH to the arrangement of large crystals, the strength of a weak  area within the concrete.