Development of non-air entrainment and internal hydrophobic porous powder for high performance of concrete

本研究的目的是开发一种无引气、内部疏水的多孔粉体，以建立一种有助于提高AE混凝土抗冻性和减少因引气引起的强度下降的新技术，结果表明，当ALC用作多孔粉体材料时，可以通过改变硅油的添加速率和类型、紫外线处理和亲水剂对粉末表面的吸附来控制拒水性和水蒸气的吸附性能。但制备表面亲水、内部疏水的多孔粉体比较困难，而采用低水灰比的硬化水泥浆体作为多孔粉体材料，即使不具有憎水性，也不会引气，可以减少强度下降，提高砂浆的抗冻性。

In this study, the aim is to develop a non-air entrainment and internal hydrophobic porous powder in order to establish a new technique which can contribute to improve the frost resistance and reduce the strength reduction due to entrained air bubbles caused in AE concrete.As a result, when ALC was used for the material of the porous powder, it was possible to control the water repellency and the adsorption properties of water vapor by changing the addition rate and type of silicone oil, ultraviolet treatment and adsorption of hydrophilic agent to the powder surface. But it was difficult to make a porous powder having hybrid properties of the hydrophilic surface and internal hydrophobic capillary.On the other hand, when the hardened cement paste with low W/C was used for the material of the porous powder, even without water repellency, there was no air-entraining and it was possible to reduce the strength reduction and improve the frost resistance of mortar.