Civil Engineering - Building Materials - Discussion

Early gain of strength is caused due to tricalcium silicate and thus setting time too.

Tricalcium silicate responsible for early setting of cement.

Answer is wrong C3S (Tricalcium Silicate) is responsible for initial setting and Di Calcium silicate (c2s) contributes strength after 7 days.

Answer is right, When water is mixed with cement to form a paste, reaction starts. In its pure form, the finely ground cement is extremely sensitive to water. Out of the three main compounds, viz. C3A, C3S, and C2S, reacts quickly with water to produce a jelly-like compound which starts solidifying. The action of changing from a fluid state to a solid state is called 'setting' and should not be confused with 'hardening'.

Silica indicates strength aluminium indicates settings times.

How long time due to tri-calcium aluminate gains the initial setting by cement?

I think it is Tri calcium silicate.

C3S is responsible to early strength not early setting time, C3A is responsiblefor early setting time.

C3S is correct.

Properties of cement compounds These compounds contribute to the properties of cement in different ways

Tricalcium silicate, C3S:- This compound hydrates and hardens rapidly. It is largely responsible for portland cement's initial set and early strength gain.

Dicalcium silicate, C2S:- C2S hydrates and hardens slowly. It is largely responsible for strength gain after one week.

Tricalcium aluminate, C3A:- It liberates a lot of heat during the early stages of hydration, but has little strength contribution. Gypsum slows down the hydration rate of C3A. Cement low in C3A is sulphate resistant.

Tetracalcium alumino Ferrite, C4AF:- This is a fluxing agent which reduces the melting temperature of the raw materials in the kiln (from 1650o C to 1450o C). It hydrates rapidly but does not contribute much to the strength of the cement paste. By mixing these compounds appropriately, manufacturers can produce different types of cement to suit several construction environments.