GAIL (India) Limited

133.6.2 AGGREGATESa) Aggregates from natural sources shall be in accordance with IS:383. The contractor shall submit to theConsultant / Engineer-in-charge certificates of grading and compliance from the suppliers for allconsignments of aggregate. In addition at site from time to time, the contractor shall test the aggregates inaccordance with IS: 2386 parts 1, II, III and IV. The contractor shall allow for and provide all necessaryapparatus for carrying out each test and for supplying test records to the Consultant.b) For fair faced concrete, the contractor shall ensure that aggregates are free from iron pyrites andimpurities which may cause discoloration.c) The fine aggregates shall be river sand, stone dust or other approved sand. It shall be free from clay, loan,earth or vegetables matter and from salt or other harmful chemical impurities It shall be dean sharp, strongangular and composed of hard siliceous material.The grading of sand as determined by the method prescribed in IS: 2386 part I shall be within the limits ofgrading zone III given in Table 1. When the grading falls outside the percentage limits given for sievesother than 600 micron, 300 micron, and 150 micron (I.S) sieves by not more 5 percent, it shall be regardedas falling within this zone. The 5 percent can be excess submission on one more sieves.TABLE 1FINE AGGREGATEI. S. Sieve Percentage passing for GradingIV ZONEI ZONEII ZONEIII ZONE10 mm 100 100 100 1004. 75 MM 90-95 90-100 90-100 95-1002 36 mm 60-95 75-100 85-100 95-1001.18mm 30-70 55-90 75-100 90-100600 micron 15-34 35-59 35-60 80-100300 micron 5-20 8-30 8-30 20-65150 micron 0-10 0-10 0-10 0-15The maximum quantity of silt as determined by the method prescribed in IS: 2386 Part II shall not exceed8%.Stone dust shall be within the limits of Grading Zone III given in table 1. When the grading falls outsidethe percentage limits given for the sieves other than 600 micron and 300 micron (IS) sieves by not morethan 5 percent and on 150 micron sieves by not more than 20 percent it shall be regarded as falling withinthis zone. The 5 percent can be excess summation on one or more sieves.3.6.2.1 COARSE AGGREGATEThe coarse aggregate shall be crushed stone or broken stone. Coarse aggregate obtained from crushed orbroken stone shall be angular, hay, strong, dense, durable clean and free from soft, friable, thin, flat,elongated flaky pieces. The coarse aggregate should be from the approved source/quarry.Coarse aggregate River shingle or pit gravel shall be rounded, sound hard, clean, non porous, suitablygraded in size with or without broken fragments and free from flat particle of shale, clay, silt, loam andother impurities.Except where it can be shown to the satisfaction of the Consultant than a supply of properly gradedaggregate of uniform quality can be maintained over the period of the obtaining the coarse aggregate indifferent sizes & blending them in correct proportions as and when required.The maximum size of coarse aggregate shall be such that the concrete can be placed without difficulty soas to surround all reinforcement thoroughly and fill the comers of form work.