C/W Ratio for 1500, 2000, 2500 PSI Concrete

Hello everyone, I am checking through my stuff but I can't find anywhere in my references I have that show  W/C to Compressive strength relationship ranges for making concrete below 3,000 PSI.  If someone happens to have these standards I would really appreciate it if someone could post up the table or the graph for C/W ratios for 1500, 2000, 2500 PSI Concretes.

Thanks!
Frank Perez

Sources for "maximum permissible water-cement ratios for concrete when strength data from field experience or trial mixtures are not available"

http://www.hopkinsmn.com/inspections/building/concreteslabs.html  is identical to the version in ACI 318-89 and UBC-97... covers 2500 and 3000 psi. ACI 318-95 and later editions deleted this table.

http://www.ladbs.org/faq/info%20bulletins/building%20code/IB-P-BC%202002-031%20Concrete%20Proportioning%20and%20Admixture.pdf   check Table 2..covers 2000, 2500 and 3000 psi etc for three different aggregate sizes.

The best source for W/C ratios versus strength is either trial batches (field or lab) or statistical evaluation of actual field test results utilizing compressive strength tests results and W/C ratios based on known material sources.

Also one should bear in mind that when dealing with W/C vs compressive strength relationships, the W/C ratio may be lowered due to durablity considerations.

Thanks Henri2 I really appreciate it, I was planning on making some test batches to refine my mix designs, but I was curious what the base-line ratios were to use them in my initial designs.  Now if could just find one for 1,500 P.S.I.  I even called my local ready-mix provider, but when I asked the sales-operator she didn't seem to know what I was talking about and didn't want to give me the number to their engineering department...go figure

Frank  

If she assumed you were working for a competitor ready mix company then you should not be suprised at her response. However, if you work for a materials testing lab that designed mixes that may have to be supplied by the company she works for, there should be no cause for concern.

In areas of the country where construction materials testing laboratories proportion concrete mix designs, ready mix companies work closely with labs, often trying to get the labs to utilize their standard performance mixes. Nontheless, I think it is a good idea for labs who design mixes to collaborate with engineering depts of ready mix companies.

For a first trial batch, use W/C of 0.55-0.6, then adjust up for less compressive strngth.

1500 psi concrete? What would you be using that for? It is too weak to be much use. Remember that strength is seen as a proxy measure of durability and other desirable properties.

In Canadian practice most structural concrete starts at 30 mPa (4500 psi). Even sidewalks are over 3000 psi.

If you Google ‘concrete mix design programs’ the first site after the paid advertisements is

http://www.union.edu/PUBLIC/CERDEPT/FACULTY/GHALY/CONCRETE/general.htm

w/c ratio varies with size of aggregate and you also have to allow for moisture present in the aggregate in batching your concrete.

Rick Kitson MBA P.Eng

Construction Project Management
From conception to completion
www.kitsonengineering.com

Henri2: Thats what I figured she was thinking but I got a chuckle out if it, because she really seemed surprised to get that kind of question.  But she was pretty right, I'm looking at starting a little ready-mix operation in my area, which is why I am looking at information for the standardized water contents etc.  Thanks for your help, those links really helped. :)

RDK: 1,500 PSI concrete is frequently used here for things like void filler/stabilizer and temporary structures that need to be broken easily.  Also, Canada has 4 seasons and freezes, which is much harder on concrete structures than say a tropical country where it rains 280+ inches of rain per year (excellent hydration on exposed structures.  Sidewalks here do well at around 2,500 PSI.  

for low strength mixes such as void filler, trench backfill etc, typically we use between 1/2 sack and 1 1/2 sack mixes up to a maximum of about 500 psi at 28 days.  1,500 psi is still fairly hard to break up.   w/c is not specified, but slump is around 6 - 8 inches

http://www.cement.org/

PCA has a wealth of information and a phone call to your local rep might give you the answer you need

CVG: Thanks for that info :)  With the slump and the P.S.I. I think I can get pretty close to the W/C for the 500 P.S.I. filler, which by-the-way I hadn't even thought of yet