- I have reviewed many recommended procedures for adding ingredients into a mortar mixer when mixing mortar. Are there similar recommendations for grouts?
- ASTM C 476 Standard Specification for Grout for Masonry states that the cementitious materials and aggregate shall be mixed thoroughly for a minimum of 5 minutes in a mechanical mixer, with sufficient water to bring the mixture to the desired consistency. Whether mortar or grout is being mixed, the goal is to achieve a uniform blend of ingredients throughout the batch. Cement and water (or cement, lime and water) form a paste surrounding the aggregates. There should be no clumps of sand or cement (or lime) in the mortar or grout. Grout often is delivered to the jobsite ready-mixed, in which case the charging sequence is determined by the grout producer. If grout is mixed at the jobsite, materials should be added in a sequence similar to the following charging sequence recommended for mixing mortar on-site in a mechanical mixer:
- 2/3 to 3/4 of the required water
- 1/2 of the required sand
- all of the cementitious material
- remainder of the sand
- water required to reach workable consistency.
Make sure the aggregates are damp when added to the mixer. Dry aggregates can absorb water from the grout and reduce flowability.
Adding grout ingredients
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