What are the advantages and disadvantages of slump test?
If shear slump occurs, it may attain true slump in next test. It cannot differentiate in workability of stiff mixes as it shows zero slumps. In dry range, no difference can be detected between different mixes with different workability. It is not suitable for concrete formed of aggregate higher than 40 mm.
What happens if the slump test fails?
If the slump test fails, then we should reject that concrete. If the water-cement ratio is high, then the workability of concrete is increased. Still, the durability of concrete is decreased due to excessive water, which forms voids in the concrete and reduce the strength of the concrete.
What are the limitations of compaction factor test?
Disadvantages of Compaction Factor Test:
- Reduces its usefulness in the field due to the large and bulky nature of the device.
- To measure the mass of the concrete in the cylinder, the test method requires a balance.
- This test method does not use vibration and although the test is commercially available and used rarely.
What is the maximum concrete slump?
International Concrete Abstracts Portal ACI 301-101 calls for the slump to be proportioned to 2 to 4 in. (50 to 100 mm) prior to a high-range water-reducing admixture (HRWRA) being added and calls for a maximum slump of 8 in.
What is the best slump to pour concrete?
A good slump for most flatwork placed by hand: five inches. For slabs struck off with mechanical equipment: two to four inches.
What is a 4 slump?
Slump is the measure of concrete consistency and fluidity. It shows the flow and overall workability of freshly mixed concrete. Simply put, the higher the slump, the wetter the mix. Four-inch (4”) slump is very common with normal weight concrete and is a good for pumping.
What does slump test indicate?
The concrete slump test measures the consistency of fresh concrete before it sets. It is performed to check the workability of freshly made concrete, and therefore the ease with which concrete flows. It can also be used as an indicator of an improperly mixed batch.
What does a high slump test indicate?
Slump is a measurement of the workability or consistency of concrete. Accordingly, its slump rating indicates what construction application the concrete is good for. The higher the slump, the more workable the concrete. If the slump of concrete is too low, it won’t shape very easily.
What is true slump test?
True slump refers to general drop of the concrete mass evenly all around without disintegration. It may undergo segregation and bleeding and thus is undesirable for the durability of concrete. Collapse slump indicates that concrete mix is too wet and the mix is regarded as harsh and lean.
What is a good slump value?
What is the ideal value of slump? Answer 1 In case of a dry sample, slump will be in the range of 25-50 mm that is 1-2 inches. But in case of a wet concrete, the slump may vary from 150-175 mm or say 6-7 inches.
How is Slump value calculated?
In case of a shear slump, the slump value is measured as the difference in height between the height of the mould and the average value of the subsidence.
What is a positive slump test?
The test is considered positive if symptoms are increased in the slumped position and decreased as the patient moves out of neck flexion.
What is Slump test used for?
The Slump Test is a neural tension test used to detect altered neurodynamics or neural tissue sensitivity.
What is a zero slump concrete?
Zero Slump : Zero slump is the indication of very low water-cement ratio, which results in dry mixes. Collapsed Slump : This is an indication that the water-cement ratio is too high, i.e. concrete mix is too wet or it is a high workability mix, for which a slump test is not appropriate.
What is the maximum compressive strength of concrete?
In normal concrete work, the maximum compressive strength that can possibly be obtained is generally reckoned to be about 7,500 psi for a 28-day cylinder.
What is concrete workability?
Workability of Concrete is a broad and subjective term describing how easily freshly mixed concrete can be mixed, placed, consolidated, and finished with minimal loss of homogeneity.
What is SpaceCrete?
SpaceCrete : zero-slump concrete that pumps easily – to build walls with no forms.
Does AirCrete absorb water?
Aircrete absorbs water over time hence the need to add cover using materials like plaster. Expansion of the absorbed water makes the aircrete prone to cracking over time.
Is Aircrete waterproof?
Aircrete is waterproof and it will not rot or decompose in water. You can have sprinklers fitted on your roof garden and water will not seep through the aircrete waterproof roofs.