AS 1012.3.5:2015 – Methods of testing concrete Method 3.5: Determination of properties related to the consistency of concrete-Slump flow,T500 and J-ring test.
(0 Place the slump cone carefully on a stable and levelled base plate, which is free from vibration or shock. Hold the slump cone firmly in place. Position the slump cone with the larger opening coincident with the 200 mm circle on the base plate (see Figure 2). Maintain the slump cone in position while it is being filled, ensuring that no concrete can leak from tinder the cone (see Figure 3).
(g) Ensure that the procedure from the start of filling to the removal of the slump cone [i.e. Steps (h) to (1)], is carried out without interruption and is completed within an elapsed time of2.5 mm.
(h) Fill the slump cone by pouring in concrete continuously until it reaches the top edge without vibration or tamping. Over-fill the slump cone slightly and if a detachable conical collar or funnel is used (see Note) then remove this.
NOTE: A detachable conical collar or funnel may be used to facilitate filling the slump cone. The collar or funnel should not penetrate the slump cone by more than 5 mm.
(i) Strike offthe surface ofthe concrete level with the top ofthe slump cone by means of a screeding and rolling motion of the rod so that the slump cone is filled exactly. Quickly remove any concrete overflow from around the base of the mould to preclude interference with the movement of the flowing concrete and while doing so avoiding any movement or vibration of the slump cone.
j) Maintain a firm downward pressure at all times until the slump cone is removed. immediately remove the slump cone from the concrete by raising it slowly and carefully in a vertical direction, allowing the concrete to subside as it flows concentrically along the test surface. Complete the operation of raising the slump cone in 3 ±1 s in a steady vertical lift without causing any tilting, lateral or torsional movement of the slump cone and without interfering with the flow of the concrete.
(k) If the T500 time (flow rate) is required, start the stopwatch immediately the slump cone ceases to be in contact with the base plate and record the time to the nearest 0.1 second, for the spreading concrete to reach the marked 500 mm (see Figure 2) circle at any point.
NOTE: it is possible for the stopwatch to be operated by the concrete tester or another person under the concrete tester’s supervision.
(1) Wait for the concrete to stop flowing and without disturbing the base plate or concrete measure and record the largest diameter (d1) of the resulting circular spread of concrete to the nearest 5 mm. Measure and record a second diameter ((12) of the circular spread at an angle approximately perpendicular to the first measured diameter (d1), to the nearest 5 mm. [See Figure 4(a).]
If the measurement of the two diameters differs by more than 50 mm, the test is invalid and shall be repeated.
(rn) When the J-ring passing ability is required, measure and record the height of concrete at four locations just inside the J-ring bars and at four locations just outside and adjacent to the bars, the locations being at the 0, 90, 1 80 and 270 degree positions around the i-ring. [See Figure 4(b).] Record and report if blocking of aggregate has occurred.
(n) When segregation assessment is required, assess the stability and resistance to segregation of the SCC by checking the concrete spread for detectable blocking and/or segregation. Record and report as either segregated or not segregated.
NOTE: Blocking and/or segregation is detected visually. The cement paste/mortar may segregate from the coarse aggregate to give a ring of paste/mortar extending beyond the coarse aggregate. Segregated coarse aggregate may also be observed in the central area. In the case of severe segregation, most coarse aggregate remains in the centre of the ring and mortar paste moves to the periphery.