mix samples of differeing ratios.
after setting, I would do a compression test and a shear test on each mixture.
Hello guys.I got a homework and seem like I am stocked.
a)What type of experiments should be done to find the relationship between the strength of concrete and water/cement ratio.
b)what will be the range of the water/cement ratio?
It would be great if you help.Thank you!
3 answers
In the question I have some strenths and w/c ratios of some specimens and it is asking me about the range,molds?Also,How many specimens should be taken for each batch of concrete?
This is a question before we learn it,so really have some understanding problems.
This is a question before we learn it,so really have some understanding problems.
For the experiments to verify water-cement ratio, go with Bob Pursley's idea. Water is necessary for the concrete to set, but too much water will weaken the concrete. Too little will make it unworkable, and will end up having voids. Plastisizers are usually added to improve workability without adding too much water.
Also, there is usually a slump test to check the workability of the concrete, in case the concrete stayed in the truck for too long and dried up, or too much water has been added by mistake.
We used to take 3 8-inch concrete cubes, and test one after 7 days. If it fails, we test another one at 14 days. If it still fails, we test the third at 28 days. If that still fails, we will do a field testing using a rebound instrument. If that still fails, chances that it will have to be demolished.
Procedures vary from country to country, and the code itself changes with time. In the US, ACI (American concrete institute) or ASTM determines the sampling and testing procedures. In Canada, it's probably the CSA standards. Today, cubes are no longer used, replaced by cylinders.
Also, there is usually a slump test to check the workability of the concrete, in case the concrete stayed in the truck for too long and dried up, or too much water has been added by mistake.
We used to take 3 8-inch concrete cubes, and test one after 7 days. If it fails, we test another one at 14 days. If it still fails, we test the third at 28 days. If that still fails, we will do a field testing using a rebound instrument. If that still fails, chances that it will have to be demolished.
Procedures vary from country to country, and the code itself changes with time. In the US, ACI (American concrete institute) or ASTM determines the sampling and testing procedures. In Canada, it's probably the CSA standards. Today, cubes are no longer used, replaced by cylinders.