Search results
Results from the WOW.Com Content Network
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 ...
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 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.
SCC is known as self-consolidating concrete in the United States. SCC is characterized by the following: extreme fluidity as measured by flow, typically between 650–750 mm on a flow table, rather than slump (height) no need for vibrators to compact the concrete; easier placement; no bleeding, or aggregate segregation
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.
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.
Concrete is a composite material composed of aggregate bonded together with a fluid cement that cures to a solid over time. Concrete is the second-most-used substance in the world after water, [1] and is the most widely used building material. [2] Its usage worldwide, ton for ton, is twice that of steel, wood, plastics, and aluminium combined. [3]
However, this study concerned hollow concrete blocks and its results are unverified for concrete slabs. The actual value of k varies significantly in practice, and is usually between 0.8 and 2.0 W m −1 K −1. [8] This is relatively high when compared to other materials, for example the conductivity of wood may be as low as 0.04 W m −1 K −1.