Search results
Results from the WOW.Com Content Network
Self-consolidating concrete or self-compacting concrete (SCC) [1] is a concrete mix which has a low yield stress, high deformability, good segregation resistance (prevents separation of particles in the mix), and moderate viscosity (necessary to ensure uniform suspension of solid particles during transportation, placement (without external compaction), and thereafter until the concrete sets).
The flow table test or slump-flow test is a method to determine consistency of fresh concrete. Flow table test is also used to identify transportable moisture limit of solid bulk cargoes. [ 1 ] It is used primarily for assessing concrete that is too fluid (workable) to be measured using the slump test , because the concrete will not retain its ...
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.
During the 1980s, Okamura and his Ph.D. student Kazamasa Ozawa at the University of Tokyo developed self-compacting concrete (SCC) which was cohesive, but flowable and took the shape of the formwork without use of any mechanical compaction. SCC is known as self-consolidating concrete in the United States. SCC is characterized by the following:
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.
In the category of self-leveling concrete there are two main groups of materials: underlayments and toppings. An underlayment is installed over an existing subfloor to smooth it out and correct any surface irregularities prior to the installation of all types of floor coverings, including sheet vinyl, vinyl composition tile (VCT), wood, ceramic tile and carpet.
Superplasticizers (SPs), also known as high range water reducers, are additives used for making high-strength concrete or to place self-compacting concrete. Plasticizers are chemical compounds enabling the production of concrete with approximately 15% less water content. Superplasticizers allow reduction in water content by 30% or more.
The effect of the water-to-cement (w/c) ratio onto the mechanical strength of concrete was first studied by René Féret (1892) in France, and then by Duff A. Abrams (1918) (inventor of the concrete slump test) in the USA, and by Jean Bolomey (1929) in Switzerland.