𝐂𝐢𝐯𝐢𝐥 𝐄𝐧𝐠𝐢𝐧𝐞𝐞𝐫𝐢𝐧𝐠

Slump Test of Concrete — ASTM C143/C143M 1. Aim To determine the slump of fresh concrete as an indication of its consistency/workability, in accordance with ASTM C143/C143M. 2. Apparatus Slump cone (Abrams cone): Height: 300 mm Bottom diameter: 200 mm Top diameter: 100 mm Tamping rod: Diameter: 16 mm Length: approximately 600 mm Rounded end Rigid, level, non-absorbent base Scoop Measuring scale 3. Procedure 1. Dampen the inside of the slump cone and the base plate. 2. Place the cone on the level base and hold it firmly. 3. Fill the cone with fresh concrete in three approximately equal layers. 4. Rod each layer 25 times using the tamping rod. 5. When rodding the second and third layers, allow the rod to penetrate slightly into the underlying layer. 6. After rodding the third layer, add concrete if necessary and strike off the surface level with the top of the cone. 7. Remove excess concrete around the base of the cone. 8. Lift the cone vertically and steadily, without twisting or lateral movement. The lifting operation should take approximately 5 ± 2 seconds. 9. Allow the concrete to subside. 10. Measure the vertical difference between the original height of the cone and the displaced center of the top surface of the concrete. 11. Record the slump to the nearest 5 mm (¼ in.). 4. Calculation \[ \boxed{\text{Slump} = H_c-H_s} \] Where: \(H_c\) = height of the slump cone = 300 mm \(H_s\) = height of the slumped concrete at its center Example: If the height of the slumped concrete is 220 mm: \[ \text{Slump}=300-220=80\text{ mm} \] Slump = 80 mm 5. Observation Table Trial Height of cone Height of slumped concrete Slump 1 300 mm _ mm _ mm 2 300 mm _ mm _ mm 3 300 mm _ mm _ mm 6. Result > The slump of the given fresh concrete sample was __ mm. 7. Precautions The base must be level, rigid, and non-absorbent. The cone must be held firmly during filling and rodding. Rod each layer exactly 25 times. Do not twist or tilt the cone while lifting it. Lift the cone smoothly within approximately 5 ± 2 seconds. Perform the test promptly after obtaining the concrete sample. If the concrete shears off or collapses substantially, the test should be repeated according to ASTM C143/C143M; the type of slump should be noted where applicable. Reference: ASTM C143/C143M, Standard Test Method for Slump of Hydraulic-Cement Concrete.

ASTM C143/C143M — Standard Test Method for Slump of Hydraulic-Cement Concrete. ASTM slump test procedure 1. Apparatus Slump cone (Abrams cone): 300 mm high, 200 mm bottom diameter, 100 mm top diameter. Tamping rod: 16 mm diameter, 600 mm long, rounded at one end. Rigid, non-absorbent base plate. Scoop and measuring scale. 2. Sampling Obtain a representative concrete sample according to the applicable ASTM sampling procedure. Remix the sample sufficiently before testing. 3. Moisten equipment Dampen the inside of the cone and the base. Place the cone on a level, rigid, non-absorbent surface. Hold the cone firmly in position. 4. Fill the cone Fill the cone in 3 approximately equal-volume layers. For each layer: Rod 25 times uniformly over the cross-section. For the second and third layers, penetrate the previous layer slightly while rodding. The final layer should slightly overfill the cone. 5. Strike off After rodding the top layer, strike off the concrete level with the top of the cone. Clean away concrete around the base. 6. Lift the cone Raise the cone vertically and steadily, without twisting or lateral movement. Complete the lifting operation in approximately 5 ± 2 seconds. 7. Measure slump Immediately measure the vertical difference between the original height of the cone and the displaced center of the top surface of the slumped concrete. Report the slump to the nearest 5 mm (¼ in.). Important ASTM points Item ASTM requirement Number of layers 3 Rodding per layer 25 strokes Cone height 300 mm Top diameter 100 mm Bottom diameter 200 mm Rod diameter 16 mm Cone lifting time 5 ± 2 s Slump measurement Vertical difference Note: ASTM C143/C143M is specifically for determining the slump of plastic hydraulic-cement concrete. A concrete that shears or collapses significantly may require the test to be repeated, with the result interpreted according to the standard.

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