Specifications - Laserfiche WebLink

Home Browse Search

r The entrained air, as measured by the Pressure Method, ASTM C231, shall be as shown in (Table Q. Nominal Maximum Size of Coarse Aggregate(in) 2" 1" 3/4" 1.07 ACCEPTANCE TESTS Total Air Measured at Discharge from trick ( %) 2.5-5.5 6.5 4.0-8.0 A. Conformity of aggregates to these Specification, and the actual proportions of cement, aggregates, and water necessary to produce concrete conforming to the requirements set forth in Table A, shall be determined by tests made with representative samples of the materials to be used on the work. Tests will be made by an accredited testing laboratory, and approved by the Engineer. B. Cement may be subject to testing to determine that it conforms to the requirements of this Specification. Methods of testing shall conform to the appropriate specification, but the place, time, frequency and method of sampling will be determined by the Engineer in accordance with the particular need. C. Water content of the concrete shall be based on a curve showing the relation between water content and 7 and 28 -day compressive strengths of concrete made using the proposed materials. The curves shall be determined by four or more points, each representing an average value of at least three test specimens at each age, and shall have a range of values sufficient to yield the desired data, including all the compressive strengths called for on the Drawings, without extrapolation. The water content of the concrete to be used, as determined from the curve, shall correspond to the test strengths of the laboratory trial mixtures as shown on (Table D) below. Design Min. Lab. Strength Strength 7 Days* 28 Days ** 3000 2500 3500 3500 3000 4100 4000 3500 4600 * May be employed by preliminary design. ** To be used for final designs. E. In no case, however, shall the resulting mix conflict with the limiting values for maximum water - cement ratios and minimum cement contents as specified in Table A. 1 12/04 03300 -4 03 -4138