Cement acceptance tests are carried out to find out if they meet the specifications of the work; the Cement must meet the properties of resistance, consistency, flexibility, and tension. These properties may vary in the preparation and the type of Cement used in work. The most popular tests are those of resistance and consistency, but there are other types of tests to know the properties of Cement.
Type of tests
The difference in height between the top of the mold and the top of the fresh Cement is called a slump. This test is performed to evaluate the ability of the Cement to adapt to the formwork that will contain it easily. The test verifies the settlement of the Cement consists of pouring the Cement into a cone (Abrams Cone); it has a standard measure of 30cm in height, 20cm at the base and 10cm at the top; this frustoconical metal mold has a flat metal base which prevents water absorption. The test is performed with a 5/8 smooth metal rod with a rounded end for compression.
The compression test is carried out with Cement cylinders taking a sample of the Cement used in work, and they are compressed in a laboratory press until they are broken; tests are carried out at different curing times, and the compression test is one of the most used to control the quality of Cement.
The cement testing equipment, cylinders must be metallic with dimensions of 30 cm high and 15 cm in diameter; at the time of carrying out the tests, they must be located on a flat surface, without vibrations, and in a cool place that is not exposed to the sun or water. All cement tests or cement test apparatus should be performed by the same person who has knowledge of the procedure and be supervised by a professional.
Air content test
The objective of this test is to determine the air content in freshly mixed Cement from the observation of the change in volume of the Cement with a change in pressure. To carry out this test, a type A or B air content meter must be used, in the example with type A, to determine the air in fresh Cement. It consists of a 7-liter cylindrical basket (vessel) and includes a large pressure gauge, air pump, and valves.
When air is added to the equipment, the Cement is trapped. When the air is released, the Cement must return to levels similar to the initial ones. The accepted difference is 0.1% plus the correction of aggregates. This test is not applicable to lightweight aggregate Cement and porous Cement.
Cement flex test
The test observes the flexural strength is a measure of Cement traction; it is a test performed on a non-reinforced Cement beam or slab; it is measured by applying forces to Cement beams of 15 cm * 15 cm cross-section and with a length of at least three times its thickness (greater than 45cm). The ultimate strength is expressed as the Modulus of Rupture (MR) in pounds per square inch (MPa). The bending tests are between 10% and 20% of the compression tests.
There are many cement testing machine manufacturers; you can contact the best manufacturer according to your needs.