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Changes of pore water content due to drying or wetting processes cause significant volume changes of concrete in load-free specimens. They are called the shrinkage (typically causing strains between 0.0002 and 0.0005, and in low strength concretes even 0.0012) or swelling (< 0.00005 in normal concretes, < 0.00020 in high strength concretes).
Portland cement had been imported into the United States from England and Germany, and in the 1870s and 1880s, it was being produced by Eagle Portland cement near Kalamazoo, Michigan. In 1875, the first portland cement was produced in the Coplay Cement Company Kilns under the direction of David O. Saylor in Coplay, Pennsylvania . [ 11 ]
[citation needed] In the concrete and petroleum industry, however, a bag of cement is defined as 94 lb (43 kg) because it has an apparent volume close to 1 cubic foot (28 litres). [61] When ready-mix concrete is specified, a "bag mix" unit is used as if the batching company mixes 5 literal bags of cement per cubic yard (or cubic metre) when a ...
Approximately 8 acres (32,000 m 2) of soil was contaminated by wood with arsenic, chromium, and polycyclic aromatic hydrocarbons. 8% of Portland cement was used by wet weight of contaminated soil. Both in situ and ex situ processes were utilized to treat over 35,000 cubic meters of contaminated soil.
The resulting hard substance, called 'clinker', is then ground with a small amount of gypsum (CaSO 4 ·2H 2 O) into a powder to make ordinary Portland cement, the most commonly used type of cement (often referred to as OPC). Portland cement is a basic ingredient of concrete, mortar, and most non-specialty grout. The most common use for Portland ...
Bags have been used as standard measures for a variety of commodities which were actually supplied in bags or sacks. These include: Cement is commonly sold in bags of 94 pounds weight, because this is about 1 cubic foot of powdered cement. [1] Agricultural produce in England was sold in bags which varied in capacity depending on the place and ...
As a consequence, even concrete containing low-C 3 A sulfate-resisting Portland cement may be affected. [9] TSA is sometimes easily recognizable on the field when examining the altered concrete. TSA-affected concrete becomes powdery and can be dug with a scoop, or even scrapped with the fingers. Concrete decohesion is very characteristic of TSA.
Batching and mixing is done under controlled conditions. In the UK, ready-mixed concrete is specified either informally, by constituent weight or volume (1-2-4 or 1-3-6 being common mixes) or using the formal specification standards of the European standard EN 206+ A1, which is supplemented in the UK by BS 8500. This allows the customer to ...