Self consolidating concrete spread test
That is probably why, up until now, a simple slump window requirement was enough, in conjunction with good consolidation practices, to lead to dense concrete elements in most applications.With SCC, other rheological requirements are needed to obtain good consolidation since no additional placing operations will compensate for any lack of rheological performances.
However, the performance criterion remains the only objective means to evaluate the adequacy of an SCC mix.
Since criterion relates to measurements, test procedures need to be developed.
This test is mostly used for evaluating the SCCs self-compactibility as it mainly relates to its yield stress.) simulate the casting process by forcing an SCC sample to flow through obstacles under a static pressure.
The final height H and H2/H1 for the U-box and the L-box respectively are recorded.
By 1988, the concept was developed and ready for the first real-scale tests.
The first paper on SCC was presented at the second East-Asia and Pacific Conference on Structural Engineering and Construction (EASEC-2) in 1989, followed by another presentation at an Energy Diversification Research Laboratories (CANMET)/American Concrete Institute (ACI) meeting in 1992.
In addition, that earlier type of concrete was not used in civil engineering structures with normal durability requirements because they either contained too much water or were not stable and led to unacceptable heterogeneity in the structure.
Reduction of the coarse aggregate content in order to reduce the friction, or the frequency of collisions between them, increasing the overall concrete fluidity; Increasing the paste content to further increase fluidity; Managing the paste viscosity to reduce the risk of aggregate blocking when the concrete flows through obstacles.
They provide indication on the static and dynamic segregation resistance of an SCC as well as its ability to flow through reinforcements.