The Slump is performed according to the procedures mentioned in the ASTM C143 standard in the United States, IS 1199 – 1959 in India, and EN 12350-2 in Europe. Generally, the value of the concrete loss is used to find workability, which indicates the water-cement ratio, but there are several factors, including material properties, mixing methods, dosing, additives, etc. also affect the
Concrete Slump Test Procedure, Applications & Types of Slump
The size of the concrete slump concrete directly reflects the quality of mobility, transport resistance of concrete slump increases and decreases. Pumping concrete slump is generally within the range of 8 ~ 18cm, for long distance and large pumping height generally be strictly controlled at about 15cm.
2/3/2015 · Hydration process of cement generates heat, which is also a cause of slump loss. The process of hydration can be retarded by keeping the temperature of the concrete low. At low temperature the slump loss is also slow. Use of ice flakes by replacing some amount of water is resorted to reduce the slump loss.
Pumping experts approximately agree that the pressure required to push 100 mm slump concrete through 200 m of horizontal 100 mm diameter steel pipe at 25 m³/h is 33 bar when pumping continuously, which is 6 m per bar. Putting all this together we get the
Low-Slump-Loss Superplasticized Concrete Mario Collepardi, Department of Materials Science, University of Ancona, Italy Pumping, for example, or transportation with buckets, particularly in hot weather, or v1bration of the in-place concrete to difficult for
25/4/2013 · All concrete has slump loss or it would never harden. In the normal slow congealing we call 'setting', the concrete first gradually loses all its slump and then proceeds to harden. However… What can be a cause for concern to the concrete user is an abnormally high rate of slump loss…
Slump Loss When Pumping? - Concrete Engineering general
A project in June during the pouring of C30 beam slab, found that the loss of concrete slump very quickly, resulting in concrete caking in the drum. Cause analysis: The temperature of the incoming cement was found to be 80℃, and the cement was generally fine, resulting in an increase in water demand, which caused rapid slump loss when the water consumption was insufficient.
The most common factors that affect the air loss are identified as: 1. Slump of the concrete (water to cement ratio), 2. Maximum pressure on the concrete due to pumping, 3. Coarse Aggregate Factor (CAF), 4. Use of Intermediate Aggregate6.
1/11/2009 · I've had 8" slump mixes with 1/3 the shrinkage of a 4" slump concrete just due to proportioning and admixture packages. Just by changing the aggregate proportions of a given cementitious content and water content, I've gone from a 2" slump up to a 7" slump and then back down to a 5" just by increasing the coarse aggregate content and reducing the fine aggregate.
The use of retarding admixture has the main drawback of the possibility of rapid stiffening, where rapid slump loss will result in difficulty of concrete placement, consolidation, and finishing. An extended-set admixture has been developed as another retarding admixture.
25/4/2013 · Aggregates are often blamed for causing slump loss because they are dry or because they have latent absorption. Prevention Sprinkled to make aggregate wet and pre-saturate so that they will not take water from concrete after mixing or during pumping
1 - Increased slump loss 2 - Increased tendency for cracking 3 - Long term strength loss 4 - All of the above When mixing concrete, the reason for adding water to the cement is called: 1 - Hydration 2 - Add weight 3 - Extra strength 4 - Bonding 1 - Hydration
Factors affecting the workability of concrete are materials such as water content, cement concrete, sand and aggregate properties such as size, shape, grading, mix design ratio and use of admixtures. 🕑 Reading time: 1 minuteFactors affecting the workability of
14/3/2017 · Concrete slumps have ranged from 4 to 6 in.—the specification requirements—and the last truck is on site with about 12,000 cu. yd. of concrete on the ground. But then a slump test on that last
Researches show that the slump loss of fresh concrete is influenced by the mineral composition of cement clinker, the type and characteristics of aggregate, the species and dosage of admixture, the mix proportion and the construction environment, etc.
These pumps are capable of pumping 130 m3 of concrete per hour with 8 inch pipes. Squeeze pumps or peristaltic pumps are the ones that use vacuum pumping. These pumps can cover a distance of 90 m horizontally and 30 m vertically, and are capable of pumping 20 m3 of concrete per hour using 3 inch pipes. (a) Direct acting piston pump.