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e. Oil pavement repairs - Oil pavement shall have a repaired thickness equal to that existing, <br />but in no case less than 3" compacted thickness. <br />Oil base pavement shall be composed of native sand and road oil. The sand and road oii <br />will be mixed in proportion to one cubic yard (1 c.y.) of sand material per eleven (11) <br />gallons of road oil. Materials shall be mixed by mechanical means until a homogenous <br />mix is obtained. The installed mixture shall be thoroughly compacted. <br />f. Unimproved street surface repairs - Unimproved streets shall be repaired by standard <br />backfill operations as specified herein, with mechanical compaction to 95% standard <br />proctor compaction. However, care shall be taken to insure the finished backfill is of <br />similar type material to that of the existing unimproved road, i.e. sandy top soil should <br />have a similar backfill surface and not clay, shale, etc. <br />Concrete <br />Concrete for any use on this project shall be uniform and workable, and shall be mixed in a <br />central plant and transported to the job site in agitator type trucks. Tirne elapsed between the <br />addition of water to the cement and final placement of the concrete shall not exceed 45 minutes. <br />Water used for mixing shall be approved for drinking by the Texas Cornmission on <br />Environmental Quality. Coarse aggregate shall be sound, durable, and free of frozen lumps or <br />deleterious material. Gradation will meet TxDOT 2004 standard specification item 421, <br />aggregate grade #4. Fine aggregate shall consist of clean, hazd, durable and uncoated particles of <br />natural masonry sand, shall meet TxDOT 1993 standard specifications, item 421, 421.2(5). <br />Cement shall be Type I Portland cement from an approved manufacturer. No admixtures will be <br />permitted without prior approval of the ENGINEER. <br />Concrete for use in structures, paving, or where, in the opinion of the ENGINEER, a higher <br />quality mix is necessary, shall be Class A, 6-sack, with a maximum water/cement ratio of 6.0 and <br />a minimum 28-day compressive strength of 3500 psi, and a rnixture to entrain 4 to 6% air. <br />All other conerete shall be Class B- 5-sack, with a maximum water/cement ratio of 8.0 and a <br />minimum 28-day compressive strength of 3000 psi, except that pipeline blocking and <br />encasement may be Class D- 4-sack, with a maximum water/cement ratio of 8.0 and a minimum <br />28-day compressive strength of 1500 psi. <br />Concrete shall not be placed on frozen subgrade, in freezing weather, or in standing water. It <br />shall be allowed to obtain its initial set before backfilling thereon. Exposed items shall be <br />formed, with a neat finished appearance, true, plumb and square. Earth forms may be used for <br />buried items. <br />Unless otherwise specified, all reinforcing steel will be Grade 60, deformed bars. <br />Concrete for use on this project shall not be a separate pay item. <br />97 <br />