The Sulphate Resisting Cement of Dalmia is a unique product specially designed to stand the challenges of aggressive environments leading to 100 years of life to the concrete construction. The salient features which sets it apart are -
1. Exposure to aggressive environments:
The chlorides and other acidic pollutants in today’s atmosphere gradually and incessantly attack the C3A ( Tricalcium Aluminate ) contained in our ordinary cement leading to deterioration of concrete structures. Similarly the sulphate infested soil conditions also lead to disintegration of concrete structures, reducing the life of construction to 5- 7 years depending upon the concentration of the aggressive elements.
The C3A or Celite is the most vulnerable component in ordinary cements. The proportion of this component is reduced to a bare minimum of 3% in Dalmia SRC cement, making it chemical resistant even to the most aggressive environments.
The Bureau of Indian standards have specified the use of such Sulphate Resisting Cement for aggressive environments and they specified the maximum limit of 5% C3A in such cements. But to make it totally fool proof against the chemical attacks, we have f
2. Volume stability:
Volume stability is another important character of the cement that affects the durability. The volume stability of the cement is mainly influenced by two parameters viz. Free Lime and Magnesia. These ingredients, when present in cement, exhibit a strange phenomenon as explained below. While other components undergo normal hydration, they remain dormant in the beginning and goes for a late reaction which involves expansion after a period of 5-7 years, when the whole structure has totally hardened. The stress exerted by such expansion reaction leads to cracks and damage of the construction. BIS has rightly added a clause in the specification that such expansion determined through Le-chatelier tests should not exceed 10mm. You will be very happy to know that the Le-chatelier expansion for Dalmia SRC is hardly 0.5 mm, which is the least among all brands available in the market.
Similarly Magnesia, another deleterious component responsible for late expansion is limited by BIS to 6% in ordinary cements, where as its presence in our intelligently designed SRC is hardly 1%. The extremely low % of magnesia makes the concrete totally safe against expansion. The autoclave expansion is another test specified by BIS to understand such expansion and the maximum limit for autoclave expansion is limited to 0.8% by BIS. But surprisingly, Dalmia SRC possesses a very low volume expansion of 0.08% autoclave expansion, depicting the extra-ordinary volume stability of this supreme product- The DCBL SRC.
3. Corrosion Resistance:
Chloride is another deleterious content in ordinary cement that attacks the steel re-inforcement of RCC. The chloride contained in ordinary cements are highly soluble and hence the corrosion reaction initiates even when the concrete is green. The corrosion reaction of steel takes place in several stages, finally leading to the formation of Hydrated ferric Oxide, which has 6 times higher volume than original steel, which results in de-lamination of concrete cover from the underside of the concrete RCC slab, exposing the re-inforcements to further atmospheric attacks.
To protect the construction and the customer happiness, BIS has restricted the presence of chloride in cement to 0.1%, whereas Dalmia SRC is a special product, unique by itself, with only 0.009% of chloride in it making it thoroughly chloride resistant. Besides the chloride attack aggravates when the pH of concrete is lower. Unlike many blended cements like PSC, the Dalmia SRC imparts very high pH to concrete, due to the presence of calcium oxide as high as 64% against 45% present in the best variety of blended cements in the country. Due to the low lime content, there is a probability of concrete losing the pH, in case of blended cements like PSC, providing a favourable atmosphere for the Steel re-inforcements to undergo corrosion. The case is entirely otherwise for Dalmia SRC, where the lime content is 64% as mentioned before.
4. Gigantic compressive strength and economizing the project:
Above all, Dalmia Cement manufacturing units are blessed with consistent quality of cement grade Lime stone, which makes it possible to go for the most stringent quality standards and hence the compressive strength obtained for Dalmia SRC is distinctly more than 2 times of that specified in the BIS standards for all ages viz 3 days, 7days and 28days. In fact, the compressive strength achieved for this product in one day is more than 2 times the 3days strength specified by BIS. This offers mighty strength to the concrete structures with extreme degree of durability and enables higher grade of concrete with cement content lower than that specified for the grade. There is also a possibility of reducing the cement content for a given grade of concrete if the same can be replaced with fine mineral admixtures to economize your project.