i. How and why do we test ii. What does it tell us about the mix iii. What is expected to happen over time as we are testing compressive strength?

What is your recommendation for the maximum size of coarse aggregate for the following situation? A reinforce concrete column with the cross-section showed in figure below have the dimensions of 300*300 mm and the clear space between reinforcement and form of 50 mm. The minimum clear space between reinforcement is 180 mm. -180 mm 150 mm 300 mm

pls show me a solution.

Concrete is required for a column that will be Severe Exposure to freezing and thawing. The cross section of the column is 300 × 300 mm. The smallest spacing between reinforcing steel is 40 mm. The specified compressive strength of concrete at 28 days is 40 MPa with a slump of 25 to 50 mm. The properties of materials are as follows: (a) Cement used is type I Portland cement with a specific gravity of 3.10. (b) The available coarse aggregate has a maximum size of 23 mm, a dry-rodded unit weight of 1800 kg/m3, a bulk specific gravity (SSD) of 2.68, absorption capacity of 0.65%, and moisture content (SSD) of 0.27%. (c) The fine aggregate has a bulk specific gravity (SSD) of 2.75, absorption capacity of 1.5%, a moisture content (SSD) of 2.5%, and a fineness modulus of 2.7,The aggregates conform to the ASTM C33-84 requirements for grading.