MORD 506 Open Graded Pre Mix Carpet (OGPC) 20 mm thick pre mix carpet Aggregate 13.2mmchips = 0.18cum 11.2mm chips = 0.09cum 2/3rd of aggregate to be retained on 11.2mm sieve (13.2mm = passing 22.4 & retained on 11.2mm sieves 11.2mm chips passing 13.2mm retained on 5.6mm sieves) Binder Bitumen @ 14.6 kg/10sqm Emulsion @ 21.5 kg/10sqm AIV < 30%, FIV < 25% and WA < 1% for coarse aggregates. 06cum 6.36 cu.2mm sieve.7mm for type C 0.2.09cum If OGPC+SC type A/C are done. Quantity of chips per 10sq.m .8 12 to 14 6.8 4.m is 0.7mm chips Per 10sqm Bitumen kg Emulsion kg 9.7mm chips (passing 11. 50% chips to be retained on 11.12.510.36mm sieve) for type A 0.09cum Sand or grit (for type B) passing 2.2 6.2 mm and retained on 2.36mm sieve and retained on 180 micron sieve 0.MORD 508 Seal Coat Table 500. Requirement of materials for seal coat Type of seal coat Type A Liquid seal coat Type B Pre mix seal coat Type C Pre mix seal coat using 6.5% by weight of total mixture 10 to 12 9 to 11 Quantity of chips per 10sqm as per cl. 2mm and 11.2mm chips at 0.2 and 11.m/10sq.8kg/10sq.9cu. Total quantity of chips: 36mm loose thickness.09 cum /10sq.7mm chips retained on 2.m on OGPC layer > application 0.m of bitumen >spreading > sectioning > compacted to a minimum thickness of 20mm > application of bitumen at the rate of 9.7mm chips at 0.m Bitumen application at 9.27cum/10sq.m of 6.2mm chips at the rate of 0.m OGPC with a mixture of 13. Compacted thickness in the range of 26 to 28mm .m Type A seal coat with 6.OGPC layer 20mm thick with 13.27cum and pre mixed with 14.8kg/10sq.36mm IS sieve > rolling OGPC with Type A Liquid seal coat.6kg/10sq. 2mm and 6.7mm into 20mm compacted layer? How much loose quantity is required for 20mm compacted layer? Requires 35% extra for open graded mixes. 27mm loose quantity is specified For SDBC and BC. For MSS.2mm. . 11. in which dust content is around 30%. Is it possible to compact a total quantity of 36mm loose thick material of 13. about 40% extra thickness is specified.Checking width of OGPC + SC. They can also find out the quality and quantity of chips used. Compacted thickness specified = 20mm. Measuring thickness is also done and it is used in arriving at the bitumen content. More the thickness more is the bitumen requirement. Final Bitumen Content is arrived by multiplying by a factor of 20mm/observed thickness. Bitumen Content = 14.Bitumen Content(BC) in OGPC + SC/MSS Present practice in AP PR Quality wing is to cut a square cake of 150mm×150mm in OGPC/MSS layer and extracting bitumen from it and calculating bitumen per 10sq. It is not being done.m or 27mm loose thickness.m proportionally.m for type B MSS. Bitumen Content = 19Kg/10sq.m or of 27mm loose thickness. Compacted thickness specified = 20mm. quantity of chips = 0.27cum/10sq.6Kg/10sq. For MSS. bitumen content may be assessed accurately by multiplying by a factor of 20mm/ observed thickness as compacted thickness is specified as 20mm .27cum/10sq. quantity of chips = 0.m In MSS or OGPC without seal coat. For OGPC. the thickness is more and the quality engineers find it deficient in bitumen content. If the quality engineers calculate the quantity and quality of chips used after extraction of bitumen from 150mm×150mm cake. 20mm thickness can be achieved only if a total quantity of chips of 27mm loose thickness are used.Bitumen Content(BC) in OGPC + SC/MSS However in OGPC+Seal coat. This assumption is directly results in bad quality work and causing immense loss to the department. the required compacted thickness is not specified. Unfortunately PR quality engineers are assuming that the compacted thickness required is 20mm only even after application 9mm thick loose quantity of 6. they would have realized the grave mistake in their assumption . The wrong assumption that the total compacted thickness is 20mm irrespective of seal coat chips is forcing the contractor to use less quantity of chips than specified to satisfy bitumen content requirement. When a total quantity of 36mm chips are used the compacted thickness is 26mm to 28mm. If he uses correct quantity of chips.7mm chips. m 17% 8 27 0.365 cu.27 cu. After compaction.m 12% 5 24 0. % chips to be retained on 11.Thickness.m 15% 7 26 0.35 cu.29 cu.36cu.m from some QC test pits S.m 32% Note: In OGPC + Type A or C Seal coat.m 14% 6 25 0.33 cu.m per 10sq.2mm sieve is 50% before compaction.m extracted sieve 20 0. %retained on 11.m 26% 9 28 0.275 cu. total quantity of chips to be used is 0.2mm thickness in mm 10sq. it may reduce upto 35% .355 cu.m 9% 2 21 0.m 12% 4 23 0.m.m 11% 3 22 0. Quantity of chips obtained.No 1 Observed Quantity of chips per % retained on 11.2mm sieve in different BT wearing coats per 10sq.26 cu.31 cu. 80 kgs/10sqm ** Bitumen content is 6. i.75m carriageway (2014-15 rates) S.5kgs/10sq. .00 % BT 1050060.00 5 OGPC 20 mm thickness+Seal coat Type A 992851.No Description of Item Amount 1 SDBC 25 mm thickness With 5.00 4 MSS Type B 20 mm thickness 758438.m.e.00 7** OGPC 20 mm thickness+Seal coat Type C 919763.00 3 MSS Type B 25 mm thickness 874538.50 % by weight of mix as Per MORD.00 * Bitumen content is 6.Comparative cost of different bituminous courses per km of 3.00 6* OGPC 20 mm thickness+Seal coat Type B 922951..00 2 MSS Type A 25 mm thickness 941813. 4. 8 of IRC: SP: 20 1 test per 500 cum or per day Thickness - regularly . Frequency of Quality Control Tests for OGPC or Mix Seal Surfacing Test Test Method Frequency AIV IS: 2386-part 4 1 test per 250 cu.m per source Stripping IS: 6241-1971 1 set of 3 representative specimens per source Water Absorption IS: 2386-part 3 1 set of 3 representative specimens per source Soundness IS: 2386-part 5 1 test per source Grading IS: 2386-part 1 1 test per 50 cu.MORD Table 1800.7.m of aggregates Binder Content Appendix 10.m per source FIV IS: 2386-part 1 1 test per 250 cu. . 2mm and 11.2mm chips 1501.7mm chips 1.332Kg Weight of 6. Calculation of Density of chips: Diameter of the Cylinder 100mm Height of Cylinder 113mm Volume of Cylinder 0.606Kg/cuM Density of 6.2mm chips 1.0008871cuM Weight of 13.2mm and 11.8 of IRC:SP:20) All the IRC publications IRC:SP:20.308Kg Density of 13. MORD table 1800.Calculation of percentage of bitumen for combined layer of O. IRC:SP:11: Hand book for quality control and PMGSY Quality Assurance Manuals stipulate that bitumen content is to be assessed on percentage for OGPC and MSS also.7mm chips 1474.P.550Kg/cuM .7( Appendix 10.G.C + Type A Liquid Seal coat. 27cuM 405.6Kg 419.C in 10 SqM Volume of OGPC chips (13.6÷419.334Kg 14.P.27×1501.2mm and 11.Calculation of percentage of bitumen for O.934 =3.G.476% .2mm) Weight of OGPC chips = 0.934Kg Percentage of Bitumen in OGPC mix=100×14.606= Weight of Bitumen = Weight of OGPC Mix = 0. 09×1474.887% .Calculation of percentage of bitumen for Type A seal coat in 10 SqM Volume of 6.51Kg Percentage of Bitumen in Seal coat mix=100×9.7mm chips Weight of 6.8Kg 142.550= Weight of Bitumen = Weight of Type A seal coat Mix = 0.8÷142.71Kg 9.7mm chips = 0.51 =6.09cuM 132. 4Kg Percentage of Bitumen in OGPC+Type A Seal Coat =100×24.36cuM Total Weight of Bitumen in Combined OGPC+SC = 14.8 =24.444Kg Total Volume of Combined OGPC+SC = 0.337% .6+9.51 = 562.444 =4.09 = 0.Calculation of percentage of bitumen for Combined Mix of OGPC and Type A seal coat per 10 SqM Total Weight of OGPC+Type A Seal Coat =419.934+142.4÷562.27+0.
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