strength of concrete

You can find this information in detail in any good book on concrete technology but i would suggest to refer CONCRETE TECHNOLOGY book written by A.M. Neville & J.J. Brooks chapter 6 and 7. Hope this information would be helpful

I am not 100% sure so feel free to correct me (still at uni) but to get you started:

In general the higher water content the lower the strength of the concrete, but the more workable it becomes.

Lower water content the stronger it is. Like a cake, to much liquid and it doesnt set and is not very stable. To little liquid and the materials do not bind together effectively.

If you have lots of reinforcement and small sections to fill you need it to be quite workable (medium to high slump), in order to fill all the voids.

After 28 days curing it should reach 70% strength (depending on size of pour and water cement ratio). Bigger pour takes longer to set.

Compaction: compaction can create a denser finished product, removing air voids and helping in settling the concrete around reo and filling other gaps. However over compaction can segregate the materials leading to a weaker final product (heavier material goes to the bottom).

Mixing and batching can change the strength of concrete from batch to batch. But thats all up to how accurate the adding and maintaining consistant ratios is. So if you are making several batches for one job, inconsistencies in mixing can lead to weaker sections.

There are additives that can be incorporated into the design to change the performance of the concrete. If you have a large batch or cold conditions there are accelerants to help it cure quicker. Opposite things to cure slower (retardents).

Lots more info if you search the web, but thats all i can think of from the top of my head.

This is too vast a question for the scope of this forum; you are talking about the entire subject of Concrete Technology. Our professor, Dr. Iqbal Ali, once parabled that Concrete is like a Human being; when freshly casted, concrete is like a baby needing supports, needing to be nourished else perished. Concrete also gets sick [deseases] and needs injections, like a baby ... it then gains the strength with time like a baby, then starts to take loads like a strong man..!!!

Short answer is you need to get a course on concrete technology.

Dear Friend,

Kindly refer the BOOK on "LEA's CHEMISTRY of CEMENT and CONCRETE - 4th EDITION, EDITED by PETER HEWLETT, Book No. ISBN: 0750662565 Publisher: Elsevier Science & Technology Books Pub. Date: January 2004." open this book, by down-loading.

I hope this Book (1066 Pages) will be HELPFUL to you. I could not locate the Down-Load Link in my system and I will try to retrieve the web-link and post it, so that the link can be used for down-loading.

I have down-loaded from the main link www.zone4info.com, where you have to get registered and become a MEMBER, and it is very simple procedure to get registered and then log in and you will find about 82 topics and plenty of down-loadable books/topics/details. Your Membership, once registered is PERMANENT.

Pl. try this route also, and down-load it. Any problem, pl. send message through personal messaging system available in CR4 as personal mail Id. etc NOT PERMITTED, and we have to respect this rule.

Thanks,

DHAYANANDHAN.S