Dry powder mortar, as an emerging green and environmentally friendly building material, not only ensures the quality stability of the product but also reduces environmental load, and will surely develop rapidly like commodity concrete. Cement-based self-leveling floor screed, as one of the dry powder mortars, is the most complex field in dry powder mortars from a technical point of view, and there are many factors that affect the performance of cement-based self-leveling floor screed materials.
Cement-based self-leveling screed mainly includes inorganic binding materials, polymer binders, aggregates (fillers), and admixtures, etc. The base formed after the curing of the self-leveling screed must be level, smooth, and strong, so as to lay other materials on it. If used as a surface layer, it must also have good wear resistance. Most of the inorganic binding materials used in cement-based self-leveling screed are composite of ordinary Portland cement and aluminate cement. If only ordinary Portland cement is used, the requirements of self-leveling screed cannot be met. The aluminate cement used is mainly produced by the melting method.
The main function of aluminate cement is to adjust the setting time, promote the development of early strength without affecting later strength, and suppress or compensate the shrinkage with other materials. There are two cases of the composite use of ordinary Portland cement and aluminate cement. One is that the proportion of ordinary Portland cement is larger, which is mainly used to prepare self-leveling screed used as cushioning layer; the other case is that the proportion of aluminate cement is more than ordinary Portland cement, which is mainly used to configure self-leveling screed for surface layer. The price of aluminate cement produced by sintering method is lower than that of melting aluminate cement. In order to study the feasibility of using sintering-produced aluminate cement in self-leveling screed, experiments were conducted on both melting and sintering-produced aluminate cement and compared their effects on the performance of self-leveling cement screed.
The performance of self-leveling screed prepared with melting aluminate cement was better than that prepared with sintering-produced aluminate cement, but the cost was also higher. The two different grades of sintering-produced aluminate cement were very similar in setting performance, strength, dimensional change rate, and bonding strength. We believe that aluminate cement produced by sintering method can also be used to prepare self-leveling screed with good performance.
