① glass fiber, while having high tensile strength and modulus of elasticity, but its poor alkali resistance; although alkali fiberglass and composite low-alkali cement-based, but if the use of alkali-resistant glass and ordinary portland cement composite , the alkali fiberglass still be Ca (OH) 2 erosion. Cement liquid phase mainly Ca (OH) 2 silicon-oxygen bond the glass fibers would fracture, SiO2 and Ca (OH) 2 in combination, the reaction of low calcium calcium silicate hydrate. This reaction can be carried out until all SiO2 is depleted and termination, and thus the tensile strength of glass fiber consequent significant decline until the lost enhancement effect, not only that, to generate in the glass fiber bundles of Ca (OH) 2 crystals are also it will damage the fibers gradually lose toughness and brittle. Even the composition contains a certain amount of ZrO2 (zirconium oxide) alkali silicate glass fiber cement substrate is still being eroded cement hydrates, but its erosion rate has slowed. If you use a low-alkali cement is not only costly, but also have an adverse effect on the structure of the steel. Compared with glass fiber, polyacrylonitrile fiber at pH 2 and pH equal to no change in the solution 14, which shows the chemical stability. This stability determines the dominance of polyacrylonitrile fibers. For the alkali and alkali fiber, will be eroded as a result of an alkaline environment, and how to enhance the concrete without any adverse effects, which are still being studied. Durability of glass fiber reinforced cement products has been the Achilles heel of the impact of their widespread use.
 

② mixing process in the construction of glass fiber easily agglomerate, improper operation will cause some physical harm, polyacrylonitrile fiber has good dispersion. In addition, larger diameter glass fiber, and the bulk density is about two times more polyacrylonitrile fibers, the number of terms in the same weight polyacrylonitrile fiber is far more than glass fiber, so you can play better crack resistance, seepage, impact resistance, freeze-thaw, toughening effect.