Fiber-cement compositions modified by flocculating additives

Chemical additives in the production of cement-fiber products are used to improve the properties of cement-fiber suspension and freshly formed sheets, as well as to accelerate the process of filtration and sedimentation of the solid phase in recuperators. To improve the filtration properties, flocculating additives are added to the composition of cement-fiber suspensions. The purpose of research is to establish the influence of the degree of ionic charge and the molecular weight of polyacrylamide (PAA) on the kinetics of cement hydration, the rate of precipitation of cement-fiber suspension and the strength of cement-fiber plates. According to the results of the first stage of the performed experimental studies, it was established that the deposition efficiency increases with an increase in the degree of ionic charge of PAA. At the second stage, it is determined that the amount of PAA from 0.05-0.15% by weight of cement slightly increases the normal density (NG) of the cement paste and, depending on the content, has approximately the same effect on its setting time...