Laserfiche WebLink
Colorado Legacy Land Former Schwartzwalder Mine <br /> North Waste Rock Pile Diversion Channel <br /> cylinders, and deliver test cylinders to the testing laboratory. The prescribed tests <br /> shall be made in the presence of or with the concurrence of Owner. <br /> 2. Test concrete and make test cylinders conforming to ASTM C31, C143,and <br /> C 172. Samples shall be taken at random and at the point of truck discharge. <br /> 3. Perform slump and air content tests throughout any placement as required to <br /> maintain constant quality of fresh concrete, and when directed by Engineer. <br /> 4. Field testing personnel shall remain on Site throughout placement of concrete. <br /> 5. Make not less than four test cylinders for each 50 cubic yards of concrete or <br /> fraction thereof for each day concrete is placed. Deliver to testing laboratory <br /> within 24 hours after taking cylinders. Exercise care not to damage cylinders in <br /> transit. <br /> 3.02 Laboratory Testin¢ <br /> A. An independent testing laboratory will be selected and paid by the Owner to perform the <br /> required laboratory tests. <br /> B. Laboratory will cure concrete cylinders conforming to ASTM C 192. <br /> C. Cylinders shall be tested conforming to ASTM C39. Average strength of two cylinders <br /> (same age) shall be used as result of the test. Break two cylinders at 7 days;two at 28 <br /> days; and one hold at Contractor's option. <br /> 3.03 Placing of Concrete <br /> A. Preparation: <br /> 1. Clean bonding surfaces free from laitance and foreign materials. <br /> 2. Verify that all embedded items are accurately and securely installed. <br /> 3. Place concrete on properly prepared and unfrozen subgrade and only in <br /> dewatered excavations. <br /> 4. Do not deposit partially hardened concrete or concrete contaminated by foreign <br /> materials. <br /> B. Placing Concrete: <br /> 1. Conform to ACI 304R. <br /> 2. Place within 45 minutes after mixing, except Engineer may extend the period to <br /> 90 minutes(maximum)dependent upon weather conditions. <br /> 3. Place in horizontal layers not exceeding 18 inches. <br /> Section 033053-Miscellaneous Case-in-Place Concrete Page 5 <br />