Research On Compound Additive Of Plaster For Aerated Concrete

Aerated concrete is a new kind of wall material. It has many merits, but when common plaster is used for aerated concrete, there are bad water retention, low bond strength, easy cracking and bulging, which seriously limits aerated concrete's promotion and application. Owing to these defects, a kind of compound additive with good performance was developed.Firstly, the effect of Caxboxymethycellulose, Polyacrylamide, hydroxyethyl methylcellulose, polyethylene vinyl acetate, naphthaline water-reducer, polycarboxylic acid type water-reducer, slag, fly ash on performance of mortar was researched. It was found that the compound additive is composed of fly ash, slag, hydroxyethyl methylcellulose, polyethylene vinyl acetate, and polycarboxylic acid type water-reducer. Based on principle of optimality, the optimum mix was decided. After studying the over-all properties of the compound additive, it was found that the compound additive improves the workability, water retention,toughness and the bond strength, and decreases the shrinkage of mortar.The mortar with the compound additive fits for aerated concrete. The problem that there are bad water retention, low bonding strength ,cracking, bulging when common plaster is used for aerated concrete can be well solved.By means of SEM and XRD, the mechanism of the compound additive on mortar was researched and analyzed. The model of bond interface between mortar and aerated concrete was established. After studying the damaging forms of the bond interface, the factors of influencing interface damaged, the acting forces of bond interface between mortar and aerated concrete, it was found that the compound additive improves not only the property of mortar itself, but also the property of bond surface between mortar and aerated concrete, and increases the bond strength between mortar and aerated concrete.