CONCRETE MATERIALS. A. Cementitious Material: Use the following cementitious materials, of the same type, brand, and source, throughout Project:
CONCRETE MATERIALS. Composition of mixes, production, sampling, testing and compliance to be in accordance with BS EN 206-1 and BS 8500. Mixing: The amount of water used in each batch of concrete shall be sufficient only to ensure the hydration of the cement and to give reasonable workability of the concrete. Within a maximum period of 20 minutes the concrete is to be placed where it is required and tamped or vibrated. Concrete ingredients to be measured in proper gauging boxes and mixed in proper platforms. The materials to be well mixed with a concrete mixer or by turning over by hand until the colour of the cement is distributed over the aggregate and a due proportion of clean fresh water is applied through a hose. No concrete shall be remixed after it has started to set, neither shall it be reused. Concrete shall not be tipped from a height of more than 6ft, but shall be lowered by strips or chutes. No concrete shall be mixed or placed when the air temperature is below 5°C or during any time when the aggregate or ground surface is frost bound. During frosty weather, recently placed concrete to be adequately protected. Unless otherwise specified in the Schedule of Works, the mix of the concrete shall be 1:2:4 cement: sand: aggregate. Placing: All concrete shall be thoroughly rammed into position and tamped continuously while being laid. All concrete in beams is to be consolidated with an appropriate mechanical vibrator. Types of Mixes: Ordinary prescribed mixes to BS EN 206-1 and BS 8500 using ordinary Portland cement and aggregates to BS EN 12620 and A1. Batching by weight (kg): Grade Cement Fine Aggregate Coarse Aggregate Normal Use C20P 50 115 190 Below ground (unreinforced) C25P 50 90 170 Below ground (reinforced) The finished surface of floor slabs taking tiled or sheet flooring should not vary by more than 3mm in 3m under a straight edge. Curing the Concrete: After pouring, all concrete to be protected that there will be no loss of moisture from the surface for a period of seven days when OPC is used. Protect for a period of three days when rapid hardening is used. In normal weather, loss of moisture from the surface shall be prevented by keeping it continuously wet by ponding and flooding concrete or by covering with wet hessian, straw or sawdust or continuous sprinkling.
CONCRETE MATERIALS. A. Cement: Furnish from one source for the Project. 1. Portland cement Type II:
CONCRETE MATERIALS. 1. Cementitious materials: Information showing type, manufacturing locations, shipping locations, manufacturer’s quality control reports, and certificates showing compliance with ASTM C150, ASTM C595, ASTM C618, ASTM C845, ASTM C989, ASTM C1157, or ASTM C1240.
CONCRETE MATERIALS. A. Cementitious materials and aggregates shall have proven history of successful use together, or submit evidence satisfactory to Architect that aggregate will not react harmfully in presence of alkalis in cement
CONCRETE MATERIALS. 2.2.2.1 Cement: Type GU, conforming to CSA A3001. Cement shall originate from the same mill.
CONCRETE MATERIALS. A. Materials shall be delivered, stored, and handled so as to prevent damage by water or breakage. Only one brand of cement shall be used. Cement reclaimed from cleaning bags or leaking containers shall not be used. Cement shall be used in the sequence of receipt of shipments.
CONCRETE MATERIALS. (i) Cement: Cement shall be of Portland type and shall conform to the requirements of BS 12 or equivalent. The contractor shall select only one type or brand of cement or others. Changing of type or brand of cement will not be permitted without a new mix design approved by the Engineer. All cement is subject to the Engineer’s approval, however, approval of cement by the Engineer shall not relieve the Contractor of the responsibility to furnish concrete of the specified compressive strength. Conveyance of cement by jute bags shall not be permitted. Storage in the Contractor’s silo or storehouse shall not exceed more than two (2) months, and age of cement after manufacture at mill shall not exceed more than four
CONCRETE MATERIALS. A. Source Limitations: Obtain each type or class of cementitious material of the same brand from the same manufacturer's plant, obtain aggregate from single source, and obtain admixtures from single source from single manufacturer.
CONCRETE MATERIALS. A. Cement: ASTM C150, Portland Cement Type – IA, Air Entrained.
