A pumpable cement grout and method for use thereof for grouting annular cavities. The pumpable cement grout is a mixture of a hydraulic cement, water in an amount sufficient so that the water-to-cement ratio of the grout is from about 0.60 to about 1.00 by weight, and pregenerated aqueous foam in an amount sufficient to adjust the wet density of the grout to a value of from about 48 to about 72 pounds per cubic foot. The grout is pumped into an annular cavity formed intermediate a tubular external member and an internal member disposed in the tubular external member, so that the grout fills this cavity by flowing in a generally longitudinal direction therethrough. The tubular external member may be a concrete sewer pipe, and the internal member may be a plastic liner pipe. The pressure at which the grout is injected into the annular cavity is maintained at or below a predetermined maximum pressure, so as to avoid collapsing the plastic liner pipe.