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Concrete creep is essentially the sagging of concrete over time. Creep and shrinkage of concrete are two physical properties of concrete.The creep of concrete, which originates from the calcium silicate hydrates (C-S-H) in the hardened Portland cement paste (which is the binder of mineral aggregates), is fundamentally different from the creep of metals and polymers.
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Test methods for the water-cement ratio and fineness modulus). 1919 – Effect of Curing Condition on Wear and Strength of Concrete (Describing 120 tests on cylinder-shaped samples and 300 tests on cubic samples in various moisture conditions and testing periods varying from 3 days to 4 months).
Their addition allows to decrease the water-to-cement ratio of concrete or mortar without negatively affecting the workability of the mixture. It enables the production of self-consolidating concrete and high-performance concrete. The water–cement ratio is the main factor determining the concrete strength and its durability. Superplasticizers ...
Prestressed concrete is a form of concrete used in construction. It is substantially prestressed during production, in a manner that strengthens it against tensile forces which will exist when in service.
A lower ratio leads to higher strength and durability, but may make the mix more difficult to work with and form. Workability can be resolved with the use of plasticizers or super-plasticizers. A higher ratio gives a too fluid concrete mix resulting in a too porous hardened concrete of poor quality.
The test is carried out using a metal mould in the shape of a conical frustum known as a slump cone or Abrams cone, that is open at both ends and has attached handles.The tool typically has an internal diameter of 100 millimetres (3.9 in) at the top and of 200 millimetres (7.9 in) at the bottom with a height of 305 millimetres (12.0 in).The cone is placed on a hard non-absorbent surface.
The ancient Romans used a type of lime mortar that has been found to be self-healing. [8] The stratlingite crystals form along the interfacial zones of Roman concrete, binding the aggregate and mortar together and this process continued even after 2000 years and it was discovered by the geologist Marie Jackson and her colleagues in 2014.