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<br />002125 <br /> <br />Durango Pumoing Plant - Stage I <br /> <br />I. <br /> <br />Place mass structural concrete where shown on the drawings or where the depth <br />of concrete placements exceeds 3 feet or where the wall thickness exceeds 3 feet. <br /> <br />Allow a minimum of 7 days between adjacent mass structural concrete <br />placements to allow for volumetric shrinkage due to temperature rise. <br /> <br />Embed thermocouples supplied by the Govemment at locations determined by the <br />Government in the mass structural concrete to monitor the temperature rise of <br />mass concrete for a minimum of7 days. <br /> <br />~ <br /> <br />2. <br /> <br />3. <br /> <br />3.02 BATCHING, MIXING, AND TRANSPORTING <br /> <br />A. Batching <br /> <br />I. Ensure before a concrete placement is started that sufficient cement is in storage <br />at the batch plant to complete the placement and that cement is free from lumps <br />and other deleterious matter and otherwise undamaged when used. <br /> <br />2. Notif'y the Contracting Officer 24 hours before batching concrete. <br /> <br />3. Perform batching only in the presence of the Contracting Officer unless <br />inspection is waived in each case. <br /> <br />4. Dry batching will not be allowed. <br /> <br />5. Batch admixtures separately in liquid form in dispensers capable of measuring at <br />one time the full quantity of each admixture required for each batch. <br /> <br />6. Measure either by weighing or by volumetric-admixture dispensers constructed <br />and located such that the full batch quantity of each admixture can be observed in <br />a visual gauge by the plant operator. <br /> <br />7. Discharge each admixture separately into the mixing water as the water is being <br />discharged into the mixer. <br /> <br />8. Provide, maintain, and operate the batching equipment as required to accurately <br />determine and control the prescribed amounts of the various materials entering the <br />concrete mixers. <br /> <br />9. Determine the amounts of bulk cement, sand, and each size of coarse aggregate <br />entering each batch of concrete by individual weighing. <br /> <br />10. Sand and coarse aggregate may be weighed with separate scales and hoppers or <br />cumulatively with one scale and hopper. <br /> <br />11. Weigh cement and pozzolan separately with 3ft individual scales and hoppers, <br />unless the batchp1ant is equipped with automatic sequential batching controls to <br />weigh materials cumulatively with one scale and hopper. <br /> <br />12. Measure water and admixtures by weight or by volume in accordance with this <br />section. <br /> <br />13. Where bagged cement is used, it need not be weighed ifthe concrete is <br />proportioned on the basis of integral bags of cement. <br /> <br />14. Protect all concrete materials from freezing. <br /> <br />Cast-in-Place Concrete <br />03300 - 21 <br />