Abstract: Compositions of especially good properties particularly for use in the construction industry have been found which comprise a matrix of solid particles, comprising at least two groups of particle types selected from aggregate, sand and filler, embedded in a binder, which is predominantly polyethylene terephthalate, wherein the binder is present in an amount in the range of from 1 to 50% by weight. Also provided is a process for the preparation of such a composition, which comprises mixing heated particles and binder, shaping if desired, and allowing the mixture to solidify, wherein solid particles and binder are heated independently of each other prior to mixing such that on mixing the temperature of the mixture is in the range of from 230 to 300° C., and wherein the solid particles are heated to a higher temperature than the binder.