Composite cement materials for structures foundation strengthening

Строительные изделия и конструкционные материалы

There was a development of сomposite cements (CC), that include aluminosilicates (AS), obtained by enrichment of ash-to-slag mixture (up to 65 wt. %), cement clinker, and gypsum. Based on the developed CC, wide range of injection mortars, including crushed granite, was created. Injection mortars are capable of effectively fixing of underground structures foundations soils, providing high strength (25.6 MPa) with deformation modulus 10.1 GPa. These materials have percentage of water separation from 22.5 % at W/B=1 to 36.5 % at W/B=2. Viscosity indicators of these materials indicate high penetrating ability, since time for mortars to flow through Marsh viscometer is 39 and 33 seconds at W/B=1.5 and W/B=2, respectively. Effect of increasing density of injection mortars at 28 days was maximum at AS dosage of 45 wt. %, then it decreased with aluminosilicate content increase. There are high ratios of strength values on second day to those in grade age: for compressive strength 0.24 (0.20–0.22 for additive-free clinker compositions), for flexural strength 0.16 (0.15 for additive-free compositions; with AS content increase above 45 %, this ratio decreases to 0.14). High early strength makes it possible to effectively use injection mortars for urgent fixing of soils during the repair of underground structures.