Test Method C1403 is used to determine the amount of water absorbed into a mortar cube over time by capillary suction. The results are expressed in terms of grams per cm2 of surface area of the face of the cube at any given test time. C1403 is specified in Specification C1384, Specification for Admixtures for Masonry Mortars, for demonstrating compliance of mortar admixtures classified as Water Repellent. In this compliance testing, the rate of water uptake of an admixed mortar is compared to the rate of water uptake of a reference mortar made with the same mortar materials except that it does not include the admixture. For quality control testing of water repellent preblended dry mortar mixes, the reference mortar is not typically available since the water repellent additive is added during the manufacturing process prior to bagging the final product. In this case, the rate of water uptake in terms of g/cm2 is not a useful measure, in and of itself, because the rate of water uptake of a blank reference mortar is not available for comparison. The proposed new Annex A1 details a procedure that can be used to determine the relative resistance of the mortar to absorption by capillary uptake. In this procedure, the relative resistance of a mortar to absorption by capillary uptake is expressed as the amount of water absorption of the test specimen at any given test time versus the amount of water uptake of the test specimen at full saturation.
Keywordsabsorption; absorption rate; masonry mortar; water repellent;