BS 8000:2.1:1990 pdf free.Workmanship onbuilding sites Code of practice for concrete work Mixing and transporting concrete.
BS 8000:2.1 Store in a proper cement silo ensuring that:
a) the silo mechanism is cleaned regularly inaccordance with the manufacturer’s siteworkinstructions;
b) the air filter is cleaned after every delivery;
c) the inlet pipe is marked with the type of cement;d) different types of cement are kept in different silos.
COMMENTARY.Unless the mechanisms are regularlycleaned they become clogged and the feed of the cementis likely to become irregrular:
a) Store cement in a dry, weatherproof，frost-free,enclosed shed or building with a dry floor. If thefloor is concrete, store on a timber platform.
b) Stack bags closely together away from walls andnot more than eight bags high.
c) Stack bags so that consignments can be used inthe order of delivery.
of storage. Do not use if it is lumpy, withoutobtaining instructions.
COMMENTARY.It is essential that cement is kept dryand awagy from air as far as practicable. Air containsmoisture which causes an air-set in the cement,therefore by keeping the doors and windows of thestoreroom shut the supply of fresh moist air isreduced.Even in good conditions cement stored in bags can lose significant strength(20 %) after about four to sio weeks,hence the need tocheck stocks.COMMENTARY.Generally stocks of different sizes andtypes of aggregates should be separated by partitionsto ensure there is no micing.This is essential whereaggregates are stored behind the micer and loadedwith a skip and drag line. Where small quantities ofaggregates are required it may be sufficient to storethem in several heaps.
Generally large stocks of aggregate should be stored ona hard standing of lean concrete and this can be extended to accommodate the micer: The base shouldextend well beyond storage and miser area with gooddrainage towards the edges. Alternatively small quantities of aggregate can be stored on polythene ortarpaulin sheeting to assist in keeping the aggregatesclean.
The control of the water content of concrete is assistedif wet aggregates can be allowwed to drain for at leasti6 h after delivery and if they are kept covered duringlong periods of rain.It also assists if the bottom 300 mm to 6o0 mm of a stockpile is not used as thiswill be much wetter than the rest.
In very cold weather it maay be necessary to use someform of insulated covering.Polgthene sheets will keepout rain and dirt but do not offer much protectionagainst the aggregates freezing.Howvever the sheetsmay be improved by holding the sheets clear of theaggregates.BS 8000:2.1 pdf download.