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the concrete has developed a modulus of rupture of 3.8 MPa. The modulus of rupture will be determined by California <br /> Test 523. <br /> • No traffic or Contractor's equipment, except as hereinafter provided, will be permitted on the pavement before a <br /> period of 10 days has elapsed after the concrete has been placed,nor before the concrete has developed a modulus of rupture <br /> of at least 3.8 MPa. Concrete that fails to attain a modulus of rupture of 3.8 MPa within 10 days shall not be opened to traffic <br /> until directed by the Engineer. <br /> • Equipment for sawing weakened plane joints will be permitted on the pavement as specified in Section 40-1.0813, <br /> "Weakened Plane Joints." <br /> • When requested in writing by the Contractor, the tracks on one side of paving equipment will be permitted on the <br /> pavement after a modulus of rupture of 2.4 MPa has been attained,provided that: <br /> A. Unit pressure exerted on the pavement by the paver shall not exceed 135 kPa; <br /> B. Tracks with cleats, grousers, or similar protuberances shall be modified or shall travel on planks or equivalent <br /> protective material,so that the pavement is not damaged;and <br /> C. No part of the track shall be closer than 0.3-m from the edge of pavement. <br /> • In case of visible cracking of,or other damage to the pavement,operation of the paving equipment on the pavement <br /> shall be immediately discontinued. <br /> • Damage to the pavement resulting from early use of pavement by the Contractor's equipment as provided above <br /> shall be repaired by the Contractor. <br /> • The State will furnish the molds and machines for testing the concrete for modulus of rupture,and the Contractor,at <br /> the Contractor's expense,shall furnish the material and whatever labor the Engineer may require. <br /> 90-9 COMPRESSIVE STRENGTH <br /> 90-9.01 GENERAL <br /> • Concrete compressive strength requirements consist of a minimum strength that shall be attained before various <br /> loads or stresses are applied to the concrete and, for concrete designated by strength, a minimum strength at the age of <br /> 28 days or at the age otherwise allowed in Section 90-1.01, "Description." The various strengths required are specified in <br /> these specifications or the special provisions or are shown on the plans. <br /> • The compressive strength of concrete will be determined from test cylinders that have been fabricated from concrete <br /> sampled in conformance with the requirements of California Test 539. Test cylinders will be molded and initially field cured <br /> in conformance with California Test 540. Test cylinders will be cured and tested after receipt at the testing laboratory in <br /> conformance with the requirements of California Test 521. A strength test shall consist of the average strength of 2 cylinders <br /> fabricated from material taken from a single load of concrete, except that, if any cylinder should show evidence of improper <br /> sampling, molding, or testing, that cylinder shall be discarded and the strength test shall consist of the strength of the <br /> remaining cylinder. <br /> • When concrete compressive strength is specified as a prerequisite to applying loads or stresses to a concrete <br /> structure or member, test cylinders for other than steam cured concrete will be cured in conformance with Method 1 of <br /> California Test 540. The compressive strength of concrete determined for these purposes will be evaluated on the basis of <br /> individual tests. <br /> • When concrete is designated by 28-day compressive strength rather than by cementitious material content, the <br /> concrete strength to be used as a basis for acceptance of other than steam cured concrete will be determined from cylinders <br /> cured in conformance with Method 1 of California Test 540. If the result of a single compressive strength test at the <br /> maximum age specified or allowed is below the specified strength but is 95 percent or more of the specified strength, the <br /> Contractor shall make corrective changes, subject to approval of the Engineer, in the mix proportions or in the concrete <br /> fabrication procedures, before placing additional concrete, and shall pay to the State $14 for each in-place cubic meter of <br /> concrete represented by the deficient test. If the result of a single compressive strength test at the maximum age specified or <br /> allowed is below 95 percent of the specified strength,but is 85 percent or more of the specified strength,the Contractor shall <br /> make the corrective changes specified above, and shall pay to the State $20 for each in place cubic meter of concrete <br /> represented by the deficient test. In addition, such corrective changes shall be made when the compressive strength of <br /> concrete tested at 7 days indicates,in the judgment of the Engineer,that the concrete will not attain the required compressive <br /> strength at the maximum age specified or allowed. Concrete represented by a single test that indicates a compressive strength <br /> of less than 85 percent of the specified 28-day compressive strength will be rejected in conformance with the provisions in <br /> Section 6-1.04, "Defective Materials." <br /> If the test result indicates that the compressive strength at the maximum curing age specified or allowed is below the <br /> specified strength,but is 85 percent or more of the specified strength,payments to the State as required above shall be made, <br /> unless the Contractor, at the Contractor's expense, obtains and submits evidence acceptable to the Engineer that the strength <br /> of the concrete placed in the work meets or exceeds the specified 28-day compressive strength. If the test result indicates a <br /> Contract No. 10-OM7104 <br /> 89 <br />