Precast concrete plates

Abstract

A precast concrete plate, such as a roof tile, floor tile, wall tile or house siding, comprises in total from about 0.2% to about 5% by weight of a polymeric modifier having a Tg of above −40° C. The portion of said concrete which comprises no more than about 50% of the thickness of all the concrete which forms the plate, when measured from the bottom surface of the plate towards the top surface of the plate, includes at least about 60% by weight of said polymeric modifier. The plates have a relatively higher degree of resistance to flexural loadings and resistance to impact-impulse loadings in comparison to concrete plates which comprise no polymeric modifier, thus rendering them less likely to be broken or fractured during their storage, transfer and assembly. The concrete plate is formed by superimposing a first layer of concrete possessing one composition and characteristic over another bottom layer of concrete having a different composition and characteristic with the bottom layer of concrete possessing the highest concentration of the polymeric modifier in the concrete plate.

Dependencies are inferred from the claim text.