Category: Cement

Although cement and lime are cementing materials, they have different features and properties:

During hydration of cement, heat is produced due to chemical reactions. In a large-scale construction this heat may raise the temperature of concrete to a high degree to as high as 50°C. In such cases low-heat cement has to be used or cooling methods must be employed. The test is conducted using a calorimeter adopting…

This test is conducted using a cement-mortar briquette in a tensile testing machine. The dimensions of the briquette are shown in Fig. 6.8. Figure 6.8 Standard cement-mortar briquette A 1:3 cement–sand mortar with water content of 8% is mixed and moulded into a briquette in the mould. It is cured for 24 hours at a temperature…

The Soundness Test is performed to detect the presence of uncombined lime and magnesia in cement. This test is conducted in Le Chatelier’s apparatus (Fig. 6.7). It consists of a small brass cylinder of 30 mm diameter, 30 mm height and 0.5 mm thickness, which is split along its generation with the split not exceeding…

The strength of cement can not be determined directly on cement. Instead the strength of cement is indirectly determined on cement-mortar of 1:3, and the compressive strength of this mortar is the strength of cement at a specific period. For this test, 555 g of standard sand and 185 g of cement is mixed with…

An arbitrary division has been made for the setting time of cement as the initial setting time and final setting time. Vicat’s apparatus is used for setting times also. 1. Initial Setting Time About 500 g of the cement sample is taken and water content 0.85 P, where P is the percentage of water required as per the…

Consistency Test is conducted to find the setting times of cement, viz., initial setting time and final setting time. The test is conducted using a standard consistency test apparatus, viz., Vicat’s apparatus (Fig. 6.6). Figure 6.6 Vicat apparatus with various plungers Standard or normal consistency of cement paste is defined as that water content which will…

About 100 g of cement is weighed and sieved using a 90-micron IS sieve. Air-set lumps are broken and the cement is sieved continuously in a circular and vertical motion for a period of 15 minutes. A mechanical sieve shaker may also be used. The residue left on the sieve is weighed. This weight shall…

Fineness of cement is responsible for the rate of hydration and rate of evolution of heat and hence on the rate of gain of strength. Finer the grains, more is the surface area and faster the development of strength. The fineness of cement can be determined by the following tests:

The following tests are conducted on cement in the laboratory (IS: 4031 – PT 1 to 15, 1989):