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<br /> <br />160 (3) AASHTO T 22 Compressive Strength of Cylindrical Concrete Specimens shall be performed <br />161 with at least two specimens at 7 days and three specimens at 28 days. Three additional <br />162 specimens tested at 56 days shall be required for Class H and HT concrete. <br />163 <br />164 (4) Class H and HT concrete shall include a measurement of permeability by ASTM C 1202 <br />165 Electrical Indication of Concrete's Ability to Resist Chloride Ion Penetration. The concrete <br />] 66 test specimens shall be two 2 inch thick disks sawed from the centers of two molded 4 inch <br />167 diameter cylinders cured no more than 56 days in accordance with A~iTM C 192 Standard <br />168 Practice for Making and Curing Concrete Test Specimens in the Laboratory. ' <br />169 <br />170 (5) Class H, HT and S50 concrete shall include a measurement of crackin€; by AASHTO PP 34 <br /> <br />171 <br />Standard Practice for Estimating the Cracking Tendency of Concrete. The ring shall be cured ' <br />172 in an indoor room with the temperature maintained 65°F to 75°F and relative humidity not <br />173 exceeding 40 percent. <br />174 I <br />175 (6) Class E and P concrete shall include AASHTO T 97 Flexural Strength of Concrete (Using <br />I76 <br />177 Simple Beam with Third-Point Loading) performed with two specimens at seven days and <br />four specimens at 28 days. <br />178 <br />]79 (7) Class E concrete shall include a report of maturity relationships in accordance with ASTM C <br />180 1074 with the following additions or modifications. The Contractor shall provide amulti- <br />181 channel maturity meter and all necessary wire and connectors. The Contractor shall be <br />182 responsible for the placement and maintenance of the maturity meter and wire. Placement <br />183 shall be as directed by the Engineer. <br />184 <br />185 (i) The cylinders used to establish the compressive strength vs. maturity relationship shall be <br /> <br />186 <br />cast and cured in the field in conditions similar to the project. , <br />187 <br />188 (ii) These cylinders shall be tested in pairs at times which yield compressive strengths three <br />189 sets of which are at or below 2500 psi and one of which is above 2500 psi. <br />190 <br />191 (iii) Testing to determine datum temperature or activation energy will not be required. <br />192 <br />193 (iv)A test slab shall be cast at the same time and location as the cylinders. The test slab shall <br />194 have a length and width of 6 feet x 6 feet and a thickness equal to the pavement design <br />195 thickness. The maturity of the test slab, when used in the compressive strength vs. <br />196 maturity relationship from the cylinders, shall indicate that a compressive strength of <br />197 2500 psi is achieved in the required time. Slab maturity will be determined with two <br />198 probes located in the slab approximately 1 and 2 feet from the edge. The test slab shall be <br />199 covered with a blanket similaz to the one to be used on the pavement. <br />200 <br />201 Except for class BZ concrete, the maximum slump of the delivered concrete shall be the slump <br />202 of the approved concrete mix design plus 1%: inch. Except for class H and HT concrete, the <br />203 laboratory trial mix must produce an average 28 day compressive strength .at -east 1 I S percent of ' <br />204 the required 28 day field compressive strength. The laboratory trial mi:K for Class H or HT <br /> , <br /> 3-34 <br /> G \101 W0100 02WUYeporta\KP\Txhniwl speufications tlac Feor~ary 3, 2006 <br /> <br />