To ensure the same compactive effort, the number of blows per lift is increased to 56. The sample should be representative of the concrete supplied. Then again open the trap of the lower hopper. New York: McGraw Hill, Inc. Step 4:- fill the freshly mixed concrete in upper hopper part.
Let the mass be W3 kg. But it is simpler to apply a standard amount of work to the concrete and to measure its degree of compaction. During the 1970s and early 1980s the modified Proctor test became more widely used as a modern replacement for the standard Proctor test. With their assistance, you can become well prepared and can avoid having to retake exams. The slump plate should be clean, firm, level and non-absorbent.
The mould is then placed on a smooth, horizontally leveled rigid and non-absorbent surface such as a rigid plate. . After this refill the cylinder with the same sample of concrete in approximately 50 mm layers, by vibrating each layer heavily so as to expel all the air and obtain full compaction of the Concrete. Testing should always be done carefully. Reston, Virginia: American Society of Civil Engineers, 25-26.
More specifically, it measures consistency between batches. This test is most suitable for concrete having a low water-cement ratio. Low workable concrete used in Mass concreting foundations and lightly reinforced sections. Accurate amount of water, cement and sand are to be taken to avoid collapsing of sample. Collect a sample of concrete to perform the slum test. The workability of concrete has also been defined as the amount of work required to place the concrete and to compact it thoroughly.
And if the cone is in completely dry condition then dampen it using a damp cloth. Compaction factor test of Concrete Formula:- Important: The Compaction factor of concrete ranges from 0. The reason behind using low workable concrete is to minimize the thermal stresses development which is caused due to the large volume of the heat of hydration which in turn develops thermal cracks on concrete surface. Weight the partially compacted concrete thus filled in the cylinder and say it W2 kg. Now mix the fresh concrete. Maintain the consistency throughout the experiment to avoid the failure. Work is applied by dropping the concrete through a standard height into a cylindrical container.
It is held firmly in place during filling by the operator by standing on the two foot pieces provided in the slump cone. The compaction in the cylindrical container is produced by the destruction of kinetic energy of the falling concrete. The standard quantity of work is provided simply by allowing the concrete to fall under gravity through a standard distance. Thus the concrete falls on the lower hopper. Comprising two conical hoppers having a hinged trap door attached to the lower end of each hopper, allowing the concrete sample to flow freely into the cylindrical mould.
Roads vibrated by power operated machines. Also indirectly to determine of concrete consistency or stiffness. The following sections provide an explanation of how the results of compaction tests are used in the design and construction of earth fills. Close the trap door of the upper hopper. Cylinders may also be compacted by vibrating using a vibrating table.
This process is then repeated for various moisture contents and the dry densities are determined for each. A lower water cement ratio means less water, or more cement and lower workability. Data and Result The result of slump test by using the above amount of cement, fine aggregate, coarse aggregate, and water was zero slump. The concrete should be filled to the brim of the hopper and level it of with trowel. The compression test shows the best possible strength concrete can reach in perfect conditions.
It can be realized that the compacting factor test measures the inherent characteristics of the concrete which relates very close to the workability requirements of concrete and as such it is one of the good tests to depict the workability of concrete. Compacting Factor Test Lab Report Compacting Factor Test is mainly used in laboratory to determine workability of concrete. The hoppers and the mould are mounted onto a rigid steel frame and are easily removable for cleaning. This test is one of the most accurate test performed in order to determine the workability of concrete. This is a simple commun.