QUESTION 3 (20 Marks) a) Concrete is required for a structure that will be exposed to normal mild conditions in Jamaica.
Posted: Thu Apr 28, 2022 3:15 pm
QUESTION 3 (20 Marks) a) Concrete is required for a structure that will be exposed to normal mild conditions in Jamaica. The following specifications for the concrete and the raw materials are given as: Slump = 75mm Water/content (w/c ratio) = 0.5 CEMENT Relative density 3.0 COARSE AGGREGATE Relative density = 2.68 Max size = 19 mm Dry rodded density = 1500 kg/m SAND Relative density = 2.64 Fineness modulus = 2.8 i. Estimate the mass of water that is requires for 1 m' of the concrete (4 marks) ii. Determine the mass of cement needed for 10 in' of the concrete (2 marks) iii. Compute the mass of the dry aggregate for 1 m of concrete (3 marks) iv. Calculate the mass of the sand that is needed to produce 10 m' of the concrete (Assume 2% air in concrete) (4 marks) b) After 28 days of curing, 150 mm x 300 mm cylindrical samples made from the concrete, the samples were tested and failed under a load of 650kN. i. Calculate the compressive strength of the concrete? (3 marks) ii. If the unit weight of the concrete is 2,400kg/m”, estimate the elastic modulus of the concrete. (4 marks)