Want a grout mix with adequate strength, pumpability, and low cost? Then head to your nearest testing laboratory and ask for a grout mix design. DESIGN CRITERIA Consider the following criteria: Compressive strength: The compressive strength is measured in accordance with ASTM C 1019. Durability: The durability of grout is seldom an issue. The grout usually is protected from moisture saturation and thus not susceptible to freeze-thaw deterioration. Grout space: According to ASTM C 476, grouts are classified as fine or coarse depending on the maximum aggregate size. Grout must flow easily into confined spaces, so the smaller the space, the smaller the grout's maximum aggregate size must be. Consistency: Grout needs to be very fluid to be pumped or poured, to flow around reinforcing steel, and to fill a cavity leaving no voids. MATERIAL SELECTION Cementitious materials: Use portland cement meeting ASTM C 150 or blended cements meeting ASTM C 595. Aggregates: Aggregates used in grout must conform to ASTM C 404. Admixtures: ASTM C 476 doesn't allow the use of admixtures in grout unless specified by the engineer or architect or approved by the contractor.