Water/ Cemetitous Materials Ratio
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The water / cementitious (w/c) ratio is used in both tensile and compressive strength analyses of Portland concrete cement. This ratio is found from
w / c = w m / w c
where w m = weight of mixing water in batch, lb (kg); and w c = weight of cementitious materials in batch, lb (kg).
The ACI Code lists the typical relationship between the w/c ratio by weight and the compressive strength of concrete. Ratios for non-air-entrained concrete vary between 0.41 for a 28-day compressive strength of 6000 lb/in 2 (41 MPa) and 0.82 for 2000 lb/in 2 (14 MPa). Air-entrained concrete w/c ratios vary from 0.40 to 0.74 for 5000 lb/in 2 (34 MPa) and 2000 lb/in 2 (14 MPa) compressive strength, respectively. Be certain to refer to the ACI Code for the appropriate w/c value when preparing designs or concrete analyses.
Further, the ACI Code also lists maximum w/c ratios when strength data are not available. Absolute w/c ratios by weight vary from 0.67 to 0.38 for non-air-entrained concrete and from 0.54 to 0.35 for air-entrained concrete. These values are for a specified 28-day compressive strength f ’ c in lb/in 2 or MPa, of 2500 lb/in 2 (17 MPa) to 5000 lb/in 2 (34 MPa). Again, refer to the ACI Code before making any design or construction decisions.
Maximum w/c ratios for a variety of construction conditions are also listed in the ACI Code. Construction conditions include concrete protected from exposure to freezing and thawing; concrete intended to be watertight; and concrete exposed to deicing salts, brackish water, seawater, etc
March 31st, 2008 at 12:25 pm
Dear sir
i am in the process of designing a concrete mix for the main line sleepers. the required strength is
60 Mpa at 28 days. Can you suggest a suitable w/c ratio and probable ingredients of the mix. i will
be greatfull for your reply
thanks
Abid Hussain
Materials Engineer
North South Railway, KSA
April 1st, 2008 at 5:52 pm
Soon we will be adding a report on this and hope that helps all !!
Thanks
KJS
May 6th, 2008 at 5:32 pm
Dear sirs,
Congratulations, your site is extremely interesting.
I am afraid that the w/c % will have to be revised in lots of formulae due to the use of nanosilica which will be launched internationally.
a normal w/c relation will be abt. 0,3, depending the % of the nanosilica strenghts of over 80 mpa can be reached in 24 hrs., cement could be reduced or the thickness of the concrete could be reduced.
I will be glad to give you more info if wanted.
Best regards
November 5th, 2008 at 3:13 pm
Dear Sir;
I need W/B ratio vs. Compressive Strength Relationship chart for my dissertation purpose.It will be very helpful for me if i get it at the earliest. So pls do the needful.
January 17th, 2009 at 10:41 am
Dear Sir
What is The Best Quality of Water, For Concrete Mixing?
Best Regards
July 8th, 2009 at 5:35 pm
please i appreciate u and send
me examples on mix design calculation & proportion!!!
thank u!!!!!!
October 23rd, 2009 at 12:56 pm
what is W/C ratio for M15, M20, M30 & M35. Also tell me their cement content as per IS 456:2000.
Please do the needful for me. I want ans as soon as possible.
Thank u for your cooperation.
November 19th, 2009 at 8:43 am
pl.give how to conduct Bend, Rebend tests for steel.
March 2nd, 2010 at 10:26 pm
Dear Sir;
I am a QA/QC or Quality Engineer trainee sir, can u give me a proper checlist of pre and post concreting sir?with explanations sir so i can easily understand the checklist. thank you