Laserfiche WebLink
UNDERGROUND STORAGE T <br />Section 13215 — Page 14 <br />D. Concrete: Proportions to attain min ultimate compressive strength of 3000 <br />psi in 28 days, with 5.75 sacks of portland cement per cu yd of wet concrete, <br />5" max slump. Shrinkage limited to .048% at 35 days. Air entrainment <br />between 3% and 6% by volume in freshly mixed concrete. Mix and aggregates <br />as approved. <br />Mix concrete in batch machine mixer of approved type for at least 1-1/2 <br />minutes after all ingredients are in mixer. <br />Transit mixing, in lieu of mixing at site, may be approved if rate of <br />delivery, haul time, mixing time and hopper capacity are such that all <br />mixed concrete delivered is placed in forms within 90 minutes from time of <br />introduction of cement and water to mixer. When temperature of concrete <br />is 85 degrees F or above, reduce placing time to 45 minutes. <br />Place concrete immediately after mixing. Do not use concrete that has <br />begun to set. Tempering not allowed. Chuting, if used, shall be done in <br />manner to avoid segregation. In placing new concrete against existing <br />concrete, use bonding agent per manufacturer's directions. <br />Thoroughly compact concrete by means of a mechanical vibrator within 15 min— <br />utes after placing. <br />Give careful and thorough attention to curing of concrete. Keep concrete <br />and forms wet for 7 days. <br />Correct defective work as directed. <br />Appearance of exposed concrete: Horizontal surfaces, steel troweled mono— <br />lithic finish; vertical surfaces, smooth and free of fins, holes, projec— <br />tions, etc. <br />E. Damp proofing: Cover exterior face of manholes or vaults located below <br />finished grade with two coats of asphalt emulsion, clay type, ASTM D1187. <br />Thin first coat of emulsion with 20% water and apply at rate of 2 gallons <br />per 100 sq ft. Apply second coat full strength (not thinned) at rate of <br />3 gallons per 100 sq ft. Apply emulsion in uniform coat without skips, <br />thin spots or holidays. Extend damp proofing for distance of 1' on adjoin— <br />ing walls, including existing walls. <br />Allow ample drying time between coats and before backfilling. <br />F. Inserts: Anchor inserts, anchor devices, bolts, cans, and similar items in <br />place before pouring concrete. <br />G. Tests and Inspection: Provide two molded test cylinders, one for 7 day com— <br />pression tests, for each batch or pour of concrete. In addition, when <br />requested, furnish samples for testing shrinkage per Test Method California <br />#530C. <br />END OF SECTION <br />R061087:ds:la:ds:ds MAR 70 2 <br />