Slump Cone, Steel

ASTM C143 Compliant Slump Cone, Steel

Slump Cone, Steel

The Slump Cone (Abrams Cone) is used to test the slump of fresh mixed concrete. The slump cone helps determine if the concrete mix is cohesive enough to meet construction standards. 8” diameter base with 4” diameter top opening, 12” overall height. Spun from heavy gauge steel with handles and base tabs for easy assembly to base plate. Cones are plated for corrosion resistance. Handles and foot pieces are welded to the cone.

• Test concrete slump in the field.

• Seamless steel for easy cleaning.

• Handles and foot lugs plated to resist rust.

• Conical shape 8” diameter base, 4” top, 12” height.

• Meets ASTM C143

Slump Cone (Abrams Cone) Test Accessories:

• Graduated Tamping Rod, 24 x 5/8in is a round, straight steel rod used with concrete cylinder molds, slump cones and unit weight tests. The tamping rod is used for rodding, a technique used to consolidate each layer of concrete during the slump test.

• Tamping Rod, 12 x 3/8in is rounded hemispherical tips, less scale and used primarily on 4” test cylinders.

• Aluminum Scoop, 24oz, Round Mouth, #1 makes easy work of concrete sampling for slump or air entrainment testing.

• Strike Off Bar, Aluminum, 1 x 12in is used to remove excess material when molding concrete cylinder specimens and slump cone tests.

• Slump Cone Filling Funnel for Concrete is used to allow for fast and easy filling.

Having the right testing equipment ready ahead of time is key to getting accurate and timely results for the slump test.

Steel Slump Cone (Abrams Cone) Meets Test Methods:

AASHTO T119
ASTM C 143
ASTM C 143M
BS 1881

Concrete Slump in Fresh Concrete Testing

Overview

Concrete slump is a critical parameter in the construction industry, a measure of the consistency and workability of fresh concrete. The slump of concrete can change continuously from the time the batch is mixed, influenced by various factors. The concrete slump test is a simple but important procedure to determine the quality and suitability of a concrete mix for various applications. This overview will cover concrete slump test, its importance, types of slumps, factors affecting slump values and key terms related to concrete slump. Slumps less than 1/2 inch may indicate the concrete is not plastic enough.

What is Concrete Slump

Concrete slump is the measure of how much a pile of freshly mixed concrete subsides when the mold (slump cone) is removed. This test gives insight to the workability and fluidity of the concrete mix which is important for proper placement and compaction of concrete in various construction projects. Multiple portions of fresh concrete are combined into a composite sample to ensure accurate testing results.

1. Compressive Strength of Concrete Slump Test Procedure:

• Fill the cone with freshly mixed concrete in three layers

• Each tamped 25 times with the tamping rod.

• Lift the cone vertically and measure the slump. The amount of slump is the measure of the consistency of fresh concrete.

Equipment: Slump Cone

• Metal mold with 8” base diameter, 4” top diameter and 12” height.

• Base Plate: Non-absorbent flat surface.

• Tamping Rod: 5/8” diameter and 24” long steel rod.

• Measuring Scale: For measuring the average slump value.

Procedure Steps: Place the cone on the base plate.

• Fill the cone with concrete in three layers, tamping each layer 25 times.

• Strike off the top.

• Lift the cone vertically and measure the slump. Marking the slump cone with required depth levels in advance can save time and speed up the testing process.

Types of Slump

1. True Slump: The slumped concrete subsides evenly, good workability and uniform consistency. The sides of the concrete can bulge out during a True Slump.

2. Shear Slump: The slumped concrete shears and slips sideways, often due to insufficient cohesion or too much water. Portions may fall away to the sides in a Shear Slump.

3. Collapse Slump: The slumped concrete collapses completely, mix is too wet and lacks stability. Slumps greater than 9 inches may indicate a lack of cohesion and affect the reliability of the test results.

4. Zero Slump: The slumped concrete maintains its shape with minimal subsidence, very stiff mix.

Importance of Concrete Slump Test

The concrete slump test is important for:

1. Quality Control: Ensure the concrete mix meets the specified consistency and workability requirements.

2. Workability Assessment: Determine how easily the concrete can be placed and compacted.

3. Predicting Performance: Indicates potential issues with the concrete mix, too much water or poor cohesion.

4. Compliance: Ensure the concrete mix meets industry standards and project specifications.

Ensuring the concrete is adequately plastic is crucial for achieving accurate and meaningful slump test results.

Factors Affecting Slump

Several factors can influence the slump value:

1. Water-Cement Ratio: Higher water content increases workability but may reduce strength and durability due to excess water.

2. Aggregate Properties: Size, shape and grading of aggregates can affect the slump.

3. Admixtures: Chemical admixtures and concrete mixture can modify the workability and other properties of concrete to make it normal reinforced concrete.

4. Mixing Time and Method: - Proper mixing ensures uniform distribution of materials.

5. Temperature: Higher temperatures can accelerate water evaporation and affect the slump.

The standard slump test methods are only applicable to plastic concrete with coarse aggregates up to 1-1/2 inches. If the coarse aggregate is larger than this size, specific procedures need to be followed to ensure accurate testing under those conditions.

Practical Applications

1. Foundations and Footings: Ensure the concrete mix is workable enough to fill forms and provide a strong base.

2. Pavements and Slabs: Achieve the right consistency for smooth and durable surfaces.

3. Columns and Beams: Ensure proper placement and compaction for structural elements.

4. Walls: Ensure the concrete can be poured and consolidated without voids.

Advanced Considerations

1. Digital Slump Testers: Provide more accurate measurements and can record data automatically.

2. Integration with Quality Control Systems: Real-time data analysis and automated reporting improves consistency and compliance.

3. Environmental Impact: Optimize the water-cement ratio and use recycled materials to enhance sustainability.

4. Training and Certification: Proper training ensures the test is done correctly, results are reliable.

Case Studies

1. Highway Construction: Regular slump tests to ensure concrete used in highways meets specifications.

2. High-Rise Buildings: Ensure concrete has required workability for complex structures.

3. Bridge Construction: Monitor concrete consistency for durable bridges.

Regular slump tests and checks on concrete temperature during curing ensure concrete quality and consistency as it reaches the job site.

Slump Test Analysis

The slump test may be simple but provides a lot of information about the concrete mix and its suitability for various applications. This section will go into technical aspects, best practices and advanced methods of slump testing. Getting a representative sample of fresh concrete for accurate test results is critical, as per ASTM C172 guidelines.

Technical Aspects of Slump Test

1. Concrete Mix: The concrete mix composition, including type and proportion of cement, aggregates and water, plays a major role in determining the slump value. The mix must be homogeneous and representative of the improperly mixed batch being tested.

2. Slump Cone Test: The slump test is a standard method for measuring slump of concrete. The cone is filled in three layers, each tamped 25 times to ensure proper compaction. The cone is then lifted vertically and the slump is measured.

3. Slump Values: Slump values range from 0 to 250 mm. 0 slump indicates very stiff mix and 250 mm indicates very fluid mix. The ideal slump value depends on the application and required workability.

4. Hydraulic Cement Concrete: The slump test is used for hydraulic cement concrete which sets and hardens through hydration process. Water-cement ratio is a critical factor affecting the slump and overall quality of concrete.

Best Practices for Slump Testing

1. Consistency: Ensure the concrete sample is representative of the improperly mixed batch and the test is done consistently. Variations in technique or sample preparation can lead to inaccurate results even for an experienced concrete technologist.

2. Equipment Maintenance: Regularly clean and inspect the slump cone, base plate and tamping rod to ensure they are free from previous concrete residues. Proper maintenance of testing equipment is crucial for accurate measurements.

3. Environmental Conditions: Conduct the slump test in a controlled environment to minimize the impact of temperature, humidity and wind. Environmental conditions can affect the water content and workability of concrete.

4. Recording and Reporting: Record the slump value and any observations about the concrete’s behavior during the test. Detailed records are important for quality control and to address any issues that may arise during construction.

Advanced

1. Digital Slump Testing: Digital slump testers provide more accurate and reliable results than traditional methods. They can record and store data automatically, reducing human error and improving consistency. Slumps above 9 inches may indicate the concrete is not cohesive enough, which affects the significance of slump test results. While lab results may show a clear relationship, this is not always the case in real-world scenarios.

2. Integration with Quality Control Systems: Advanced quality control systems can integrate slump test data with other tests to give a complete picture of the concrete properties. Real-time data analysis allows for immediate mix adjustments to ensure consistency.

3. Environmental Impact Assessment: Modern slump testing can also include environmental impact assessment of the concrete mix. Optimizing water-cement ratio and using sustainable materials can improve the environmental performance of concrete.

Practical

1. Field Conditions: When testing in the field, pay attention to details. Make sure the base plate is level and stable and test away from direct sunlight or strong winds to prevent water evaporation. Also sieve out larger aggregates to get accurate slump of plastic concrete mixes.

2. Sample Preparation: Proper sample preparation is key to accurate slump testing. The concrete mix should be homogeneous and free from segregation. Use a representative sample from the improperly mixed batch to get meaningful results. Getting a representative sample of fresh concrete is critical for accurate slump test results.

3. Data Interpretation: Interpreting slump test results requires understanding of the project requirements. For example higher slump may be acceptable for high workability mix and lower slump may be required for structural elements.

Case Studies and Applications

1. Highway Construction: Slump testing is a must for large highway projects. Ensuring the consistency and workability of the concrete mix is critical for the durability and performance of these structures. An option to enhance efficiency during slump test is to clamp the slump cone to a non-absorbent base plate instead of standing on foot tabs.

2. Building Construction: Slump test ensures the concrete used in building construction meets the required standards for strength and workability. This is more important for structural elements like columns, beams and slabs.

3. Special Applications: For special applications like precast concrete elements or high performance concrete, slump testing gives valuable information about the mix properties. This helps to achieve the desired performance and quality of the finished product. Slump tests are necessary to document the properties and consistency of concrete as it’s used on site.

Conclusion

The slump test is a basic and widely used method to check the consistency and workability of fresh concrete. By understanding the technical, practical and advanced methods of slump testing, construction professionals can ensure the quality and performance of their concrete structures. Whether for large infrastructure projects, residential buildings or special applications, the slump test gives you the data to get the desired results. Writing down the measurements and observations during the slump test helps to document the concrete mix properties. With advancements and integration with modern quality control systems, the slump test will continue to be an essential tool in the construction industry to ensure the concrete mixes meet the required specifications.