Self consolidating concrete testing Chatalternativ

The J-Ring test, in conjunction with the Slump- Flow test, is one way to determine the passing ability of SCC, defined as the ability of the concrete to flow under its own weight to completely fill all spaces within the formwork.Depending upon the procedure selected, a modified slump cone is positioned either inverted or upright in the middle of the J-Ring and filled with concrete in a single lift.The complete HM-55 set includes the J-Ring assembly, Modified Slump Cone, high-density polyethylene Strike-Off Bar and a plastic Base Plate with convenient cut-out carrying handles. Ship Wt.: 19lb (9kg), and is inscribed with concentric circles.

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The cone is then lifted straight up and the diameter of the resulting circular flow of concrete is measured.

A similar test is then run without the J-Ring in place and the difference in the flow diameters is recorded as the passing ability.

In the case of SCC, rounded aggregates would provide a better flowability and less blocking potential for a given water-to-powder ratio, compared to angular and semi-rounded aggregates.

Moreover, the presence of flaky and elongated particles may give rise to blocking problems in confined areas, and also increase the minimum yield stress (rheology terms are discussed in the next section).

Incorporation of aggregate shape in mixture design, based on the method developed by O’Flannery and O’Mahony, is explained in Table 1.

Another deficiency in aggregates is poor gradation.

Use of fillers (either reactive or inert) has been suggested as a means of overcoming this problem. In view of on increased awareness of the environmental impact of mining river sand and depleting supplies of the same, use of manufactured sand and other alternative fine aggregate has become essential in some parts of the world.

In fact, river sand is simply not available in many areas.

The J-Ring Test Set is used to determine the passing ability of self-consolidating concrete.

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