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Creep and shrinkage can cause a major loss of prestress. Underestimation of multi-decade creep has caused excessive deflections, often with cracking, in many of large-span prestressed segmentally erected box girder bridges (over 60 cases documented). Creep may cause excessive stress and cracking in cable-stayed or arch bridges, and roof shells ...
Later in the setting phase, when the fresh concrete becomes more viscous and starts to harden, water loss due to unwanted evaporation can cause "plastic shrinkage". This occur when concrete is placed under hot conditions, e.g. in the summer and not sufficiently protected against evaporation. Cracks often develop above reinforcement bars because ...
ASTM C1293: "Test Method for Concrete Aggregates by Determination of Length Change of Concrete Due to Alkali-Silica Reaction". It is a long-term confirmation test (1 or 2 years) at 38 °C in a water-saturated moist atmosphere (inside a thermostated oven) with concrete prisms containing the aggregates to be characterised mixed with a high-alkali ...
Concrete is used to create hard surfaces which contribute to surface runoff that may cause soil erosion, water pollution and flooding. Conversely, concrete is one of the most powerful tools for proper flood control, by means of damming , diversion, and deflection of flood waters, mud flows, and the like.
Concrete has a very low coefficient of thermal expansion, and as it matures concrete shrinks. All concrete structures will crack to some extent, due to shrinkage and tension. Concrete which is subjected to long-duration forces is prone to creep. The density of concrete varies, but is around 2,400 kilograms per cubic metre (150 lb/cu ft). [1]
Concrete may be considered waste according to the European Commission decision of 2014/955/EU for the List of Waste under the codes: 17 (construction and demolition wastes, including excavated soil from contaminated sites) 01 (concrete, bricks, tiles and ceramics), 01 (concrete), and 17.01.06* (mixtures of, separate fractions of concrete ...
Lab testing has shown that subjecting a clayey soil to wetting and drying cycles leads to a hysteresis of shrinkage in the soil, significantly reducing its free swelling potential. [7] Dispersive soils, such as fine graded sands, can also pose a threat to concrete canal linings since they erode when in contact with flowing water, which can ...
Previous stresses and other changes in a soil's history are preserved within the soil's structure. [4] If a soil is loaded beyond this point the soil is unable to sustain the increased load and the structure will break down. [4] This breakdown can cause a number of different things depending on the type of soil and its geologic history.