Strength Mechanism of Cement ~ Bogue's Compounds
(i) Tri-calcium silicate (C3S): It is responsible for the gain of strength at 28 days.
(ii) Di-calcium silicate (C2S): it imparts strength to cement at a later stage due to hydration of c2s.
(iii) Tri-calcium aluminate (C3A): It is responsible for the flash setting of cement. It is also responsible for the highest amount of heat evolution.
(iv) Tetra-calcium alumino ferrite (C4AF): It hydrates very rapidly but its contribution to the overall strength of concrete is very low.
Strength Mechanism of Cement
When water is added to a mixture of concrete components, the cement reacts chemically with the water and forms a various complex chemical compounds. This chemical reaction that takes place between cement and water is known as the hydration of cement which is responsible for Strength Mechanism of Cement
Anhydrous cement cannot bind fine aggregate and coarse aggregate together it acquires adhesive property only when mixed with water
The silicates component such as C3S, C2S and aluminates component C3A of cement reacts with water and form hydro silicates and hydro aluminates. These products are thick and sticky in nature. It knows as Gel
Gel possess the adhesive property and bind fine aggregate (sand) and course aggregate together. It also fills the voids between aggregate and sand so that honeycombs effect eliminated
The hydration process of cement can be done in two ways
The first is a "through solution" mechanism, in which the cement components are dissolved in water to produce a supersaturated solution, from which different hydrated products are precipitated
Another theory is that water attack cement compounds in the solid-state converting them into hydrated products
It is probable that both ‘through solution’ and ‘solid state’ types of mechanisms occurs during the so-called reaction between cement and water
Obviously, the ‘through solution’ mechanism occurs in the early stages of hydration when a large amount of water is available. The ‘solid state’ mechanism may occur during the later stages of hydration
Authorities in the field of Cement concrete technology
Various authorities in the field of concrete technology are:
1. Indian Standard Institute (ISI) – New Delhi
It publishes standards regarding the concrete
It has developed a concrete mix design process
2. Indian Road Congress (IRC) – New Delhi
Research on materials for road construction, construction methods and other developments
3. Concrete Association of India – Mumbai
It publishes handbooks, guides and Journals on the reacher work on concrete carried out nationally as well as internationally
4. Structural Engineer Research Institute – Roorkee
Research on concrete technology and structural engineering
5. Cement Research Institute of India – New Delhi
Research on cement and its properties, uses and publications
6. Cement Corporation of India – New Delhi
7. Road Research Laboratory (RRL) – London (U.K)
Road research, concrete mix design development etc
8. American Concrete Institute (ACI) – USA
Research and development on concrete, Publication of paper, journals etc