BEDDING SAND COURSE. The bedding sand shall consist of naturally occurring, clean, well graded sand passing through 4.75mm sieve and suitable to concrete manufacture. The bedding should be from either a single source or blended to achieve the following grading. IS SIEVE SIZE % PASSING 9.52mm 100 4.75mm 95-100 2.36mm 80-100 1.18mm 50-100 600 microns 25-60 300 microns 10-60 150 microns 5-15 75 microns 0-10 Contractor shall be responsible to ensure that single-sized, gap-graded sands or sands containing an excessive amount of fines or plastic fines are not used. The sand particles should preferably be sharp, not rounded. The sand used for bedding shall be free of any deleterious soluble salts or other contaminants likely to cause efflorescence. The sand shall be of uniform moisture content, which shall be within 4% - 8%, at the time of spreading and shall be protected against rain when stockpiled prior to spreading. Saturated sand shall not be used. The bedding sand shall be spread loose in a uniform layer as per drawing. The compacted uniform thickness shall be 50mm and within 5mm. Thickness variation shall not be used to correct irregularities in the base course surface. The spread sand shall be carefully maintained in a loose dry condition and protected against pre-compaction both prior to and following spreading. Any pre-compacted sand left overnight shall be loosened before further laying of paver blocks takes place. Sand shall be slightly spread in a loose condition to the predetermined depth only slightly ahead of the laying of the paver block. Any depressions in the spread sand exceeding 5mm shall be loosened, raked and re spread before laying of paver block. 5.6.3
