Laserfiche WebLink
n <br />u <br />L <br />u <br />it <br />u <br />1 <br />C. All central plant and rolling stock equipment and methods shall conform to the latest Truck <br />Mixer and Agitator Standards of the Truck Mixer Manufacturers' Bureau of the National <br />Ready -Mixed Concrete Association, as well as ACI Standard 304 and ASTM Specification <br />C94. <br />D. The re- tempering of concrete or mortar which has partially hardened, that is, mixing with or <br />without additional cement, aggregate, or water, will not be permitted. <br />E. Attention is called to the importance of dispatching trucks from the batching plant so that <br />they shall arrive at the site of the work just before the concrete is required, thus avoiding <br />excessive mixing of concrete while waiting or delays in placing successive layers of <br />concrete in the forms. <br />3.03 FIELD TESTS <br />A. Sets of four field control cylinder specimens will be taken at random by the Engineer <br />during the progress of the work, in conformity with ASTM Designation C31; the total <br />number of specimens taken on the project may average one set per 150 cubic yards, and in <br />general not less than one set of specimens will be taken on any one day when concrete is <br />being placed. When average ultimate 28 -day strength of control cylinders in any set falls <br />below the required ultimate strength or below proportional minimum 7 day strengths where <br />proper relation between 7 and 28 day strengths have been established by tests, proportions, <br />water content, or temperature conditions shall be changed to secure the required strength. <br />B. The Contractor shall cooperate in the making of such tests to the extent of allowing free <br />access to the work for the selection of samples, providing heated (when required) moist <br />storage facilities for specimens, affording protection to the specimens against injury or loss <br />through his operations, and furnishing material and labor required for the purpose of taking <br />concrete cylinder samples, curing boxes and shipping boxes. All shipping of specimens will <br />be paid for by the Owner. <br />C. Slump tests will be made in the field by the testing laboratory. <br />3.04 INSPECTION AND CONTROL <br />A. The preparation of forms, placing of reinforcing steel, conduits, pipes, and sleeves, <br />batching, mixing, transportation, placing and curing of concrete shall be at all times under <br />the inspection of the Engineer. <br />B. The Contractor shall engage the services of an approved testing laboratory to establish the <br />basic mixtures of concrete as required by the specifications. <br />C. The Owner will engage the services of a testing laboratory to test field control cylinder <br />specimens and to conduct other tests as specified herein or as deemed required by the <br />Engineer to insure the quality. <br />D. Air entrainment shall be measured by the testing laboratory or his representative at time of <br />concrete deposit in accordance with ASTM Designation C231. <br />3.05 CONCRETE APPEARANCE <br />1 12/04 <br />A. Concrete for every part of the work shall be homogeneous structure which, when hardened, <br />will have the required strength, durability and appearance. <br />B. Formwork, mixtures and concrete placement workmanship shall be such that concrete <br />surfaces, when exposed, will require only minimal finishing with no excess honeycombing, <br />voids or irregular color lines. <br />03300 -7 03 -4138 <br />