SS 73 Pt.20-1992 Methods for sampling and testing of mineral aggregates,sand and fillers Part 20: Methods for testing and classifying drying shrinkage of aggregates in concrete
This Part of SS 73 describes the method for classifying the drying shrinkage of aggregates for use in concrete. It applies to aggregate combinations where the coarse aggregate nominal maximum size does not exceed 20 mm and uses concrete prisms made with the coarse and/or fine aggregate to be tested.
NOTE 1. In those cases where the drying shrinkage of a source of coarse aggregate only or a source of fine aggregate only is required, the other component to be used should be, respectively, a fine or coarse aggregate of known low shrinkage.
NOTE 2. Aggregates are generally used in a moist condition. However, this procedure uses constant mass proportions and aggregates prepared in an oven dry condition to minimize practical difficulties in carrying out the test. This may have an influence on the shrinkage value obtained and makes the method inappropriate for determining the shrinkage of particular concrete mixes.
The use of constant mass proportions imposes some restriction on the applicability of the procedure. Experience is limited to aggregates having oven dry particle densities not less than 2450 kg/m3 and to aggregate combinations in which the weighted combined water absorption is not greater than 3.5 % by mass when tested according to BS 812 : Part 107 or equivalent Singapore Standards. Caution is necessary when interpreting results for aggregates with properties outside these values or where difficulty is experienced in compacting the specimens but advice on testing such aggregates will be given in a new BRE Digest on the shrinkage of natural aggregates in concrete (see foreword).
NOTE 3. The titles of the publications referred to in this standard are listed at the end of the standard.
SS 73 Pt.20-1992 history
1992SS 73 Pt.20-1992 Methods for sampling and testing of mineral aggregates,sand and fillers Part 20: Methods for testing and classifying drying shrinkage of aggregates in concrete