A new competitive class of grouting materials has been created. These lightweight grouting materials (LGM) with a density of 1370–1650 kg/m3 consist of oil well Portland cement PCTI-100, fine powder of PE grade (a by-product of fireclay production from kaolin), acidic fly ash from state district power plants, and lime dust (a by-product of lime production). The composition of the products formed during LGM hydration was clarified by X-ray phase and differential thermal analysis. The rational optimal ratios of ingredients and temperature regimes for the LGM hardening were determined according to the criteria of cement stone strength.
