Slump Flow Test for Self-Compacting Concrete SCC
Significance
The slump flow test is fundamental. it’s used to evaluate the workability and flowability of self-compacting concrete (SCC). It provides valuable information about the ability of SCC to flow and fill complex formwork without segregation or blocking. The test helps ensure that SCC meets the required fresh concrete properties for successful placement and compaction.
Standard
The droop drift check for SCC is usually achieved consistent with ASTM C1611/C1611M, “Standard Test Method for Slump Flow of Self-Consolidating Concrete.
ACI 237R-07 (Self-Consolidating (Compacting) Concrete)
EN 12350-8 relates to the testing of clean concrete, in particular focusing on self-compacting concrete through the droop-flow check.
CSA A23.1/A23.2 necessities embody recommendations for Concrete Materials and Methods of Concrete Construction, in addition to Methods of Test and Standard Practices for Concrete.
Scope
The purpose of this take a look at is to decide the slow drift of SCC, which measures the flowability and workability of the concrete combination. The take a look at presents an indication of the filling capacity of SCC and is very critical for quality management throughout concrete production and placement.
Aim
This test intends to determine the hunch waft of self-compacting concrete and inspect its workability and flowability.
Objective
The cause of this take a look at is to:
- Measure the slump flow of SCC using the slump cone method.
- Evaluate the flowability and workability of SCC based on the slump flow results.
Apparatus and Equipment
- Slump Cone: Slump cone Height 300 mm, top diameter 100 mm, bottom diameter 200 mm.
- Non-absorbent base plate: A thin, inflexible plate with a minimum dimension of six hundred mm by way of 600 mm (24 inches by using 24 inches).
- Tamping Rod: Tamping rod with a spherical head, approximately sixteen mm in diameter and six hundred mm in duration.
- Measuring Scale: A measurement of concrete volume.
- Stopwatch: A stopwatch to record the time taken for the concrete to flow.
Theory
The slump flow test measures the flowability and workability of SCC. The test involves filling a slump cone with SCC, removing the cone, and measuring the diameter of the concrete spread. The slump flow value indicates the ability of SCC to flow and fill without separating or blocking the formwork. A higher slump flow value indicates better flowability and workability of SCC.
T50 Slump Flow test
The T50 slump flow test evaluates the workability of fresh concrete by measuring its flow. It quantifies the spreading diameter of the concrete 50 seconds after it’s far released from the funnel-shaped field. Higher values of T50 imply better workability of concrete, even as lower values suggest less achievable and more potent concrete. These exams are vital to make certain that the concrete meets production requirements and include factors consisting of mix layout, liquid cement proportions, and temperature.
Procedure
- Prepare the slump cone
- Ensure the slump cone is clean and free from any hardened concrete or debris.
- Moisten the inside surface of the cone with water.
- Conducting the test
- Place the slump cone on the non-absorbent base plate.
- Load the slump cone with the freshly mixed concrete in three evenly distributed layers.
- A tamping rod is used to tamp each layer, tamping will be done by inserting the rod into the concrete and distributing the blow evenly throughout the cross section of each layer Tamping is usually as shown, with 25 strokes per layer in, evenly distributed across the cross-section.
- After tamping the third layer, strike off the excess concrete from the top of the slump cone using a trowel or straightedge, ensuring a level and smooth surface.
- Lift the slump cone vertically upward, allowing the concrete to flow freely and spread out.
- Use a ruler or tape measure to measure the diameter of the expanded concrete at the widest point perpendicular to the direction of flow.
- Record the slump flow value in millimeters.
Calculation
The formula for calculating the Slump Flow is simply the recorded diameter of the concrete spread:
Slump Flow = Diameter of concrete spread
The Slump Flow is typically expressed in millimeters (mm). It represents the average diameter of the concrete spread and provides an indication of the workability and flowability of the concrete mixture. A higher slump flow value indicates a more fluid and flowable concrete mixture.
Maximum Slump Flow for SCC Concrete
- ASTM C1611 is a standardized test method that specifies methods for measuring the slow flow rate of self-cured concrete.
- Maximum flow reduction is 750 mm (30 inches) .
- EN 12350-8 pertains to the testing of fresh concrete and specifically focuses on Self-Compacting Concrete through the Slump-flow Test:
- Maximum Slump Flow: 800 mm
- ACI 237R-07 (Self-Consolidating (Compacting) Concrete):
- Maximum slump flow is 650 mm (26 inches)
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CSA A23.1/A23.2 specifies standards for concrete materials, concrete production methods, and methods and standard practices for concrete testing:
- Maximum slow flow: 800 mm (31.5 inches) .
General Acceptance Criteria for Self Compacting Concrete SCC Workability
- Slump Flow: SCC should have a slump flow value within a specified range. Slump flow is a measure of the SCC’s ability to flow and spread without segregation. Example acceptance criteria for slump flow can be between 500 to 650 mm (20 to 26 inches).
- T50 Time: T50 time represents the time taken for SCC to reach half of its final spread diameter during the slump flow test. It is an indication of the SCC’s flowability. Example acceptance criteria for T50 time can be within 2 to 5 seconds.
Conclusion
The slump flow test provides valuable information about the flowability and workability of self-compacting concrete. The measured slump flow value helps evaluate the ability of SCC to flow and fill complex formwork without segregation or blocking. Optimizations for the workability and flowability of SCC can be made based at the stoop float consequences, together with modifications to the mixture layout, along with water content material or admixture dosage.
Recommendation
Based at the slump drift effects, optimizations for the workability and flowability of SCC may be made, which includes changes to the mixture layout, consisting of water content material or admixture dosage. It is important to observe the advocated hints and requirements for undertaking the stoop glide test to make certain consistent and reliable results.
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