Cement is an important part in any construction activities; and naturally scores of problem and haggling take place between contractor and client on Cement – The Cement Company and the Mix Design.
Inorder to make your life easy if you are the project manager or have faced the similar problem. Below given are five ways to save cement in concreting.
Using Water retarder :-
The IS Code says for M25 the water ratio should be between 0.5 to 0.65. Now it means that the content of the cement is guided by the Water ratio. Using admixture like Sikka or any other equivalent will decrease water requirement and hence also cement quantity. Also note that our IS Code also says that the minimum cement content for M25 should be 300 kg/m3. Hence we cannot cross that limit, but there is another trick.
Using Fly Ash :-
It is not that we have burned lot of coal in last 100 years, that we needed to figure out how to use the side product – “Ash”; But nevertheless, with so much of Fly ash,that the scientist have found a novel way to use it – As a substitute of Cement. Now the IS Code says that one cannot mix it more then 25% of cement content as specified, But still considering the cost of cement, and the cheapness of Fly Ash, it is a very valuable idea. How does Fly Ash has concreting properties, Well this is a matter of research and many papers have been published and spoken of but in a nutshell it says that Fly Ash is not cement, but under the presence of Calcium Hydoroxide it forms chemical which has a pozollanic properties.
Using Silica fume :-
Similar to Fly Ash, Similar History like fly Ash – Waste product ; Silica Fume possess same pozollanic properties like fly ash. It has high silica content > 85. But unlike Fly Ash , which is used as a substitute of Cement; It is used as a property enhancer for cement, and is mainly used in High Performance Concrete.
Try to increase aggregate size – 40 mm :-
For Mass concreting use 40 mm aggregate, do not go for RMC without checking the design requirements. It happened in one of our mass concreting project for Foundation of OHE ( Over Head Electrical) for Metros. We keep on haggling over the price with RMC supplier; only at the end we got the trick of increasing the aggregate size to 40 mm to reduce the cement and hence reduce the price. To know more about it, check out our tutorial for Mix Design.
Finding Optimized Slump and Workability :-
Like the above mention case with haggling over with RMC vendor ; Try to work out your own slump and workability requirement. IS Code define various slump and workability requirement for foundaiton, Beams, Columnns and Slabs. If one can find the right balance of Slump and Workability; one may be able to reduce cement.
If you have any more ideas, please feel free to share in the comment section.Your ideas and views would be greatly appreciated.