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(1) Autogenous shrinkage of concrete is A. the microscopic volume reduction at a

ID: 1866305 • Letter: #

Question

(1) Autogenous shrinkage of concrete is A. the microscopic volume reduction at an early age; B. also called drying shrinkage; C. facilitated by larger w/c D. enlarged if 10% of cement is replaced by silica fume. (2) In concrete compressive strength tests, which of the following descriptions is obviously incorrect? A. The higher the loading rate, the higher the tested strength; B. The larger the specimen size, the lower the tested strength; C crhbe specinen' aprt strengh lowerer than oylinder spectimen of comparable D. All of above. (3) The relation between tensile strength and compressive strength of a concrete reads A. For a plain high strength concrete with a compressive strength of 100 MPa, its tensile strength can be as high as 20 MPa 3 The ten teseoaotes h C. Tensile strength of a high strength concrete can be higher than its compressive strength; D. None of above. (4) Which of the following descriptions fit the characteristics of the interfacial transition zone in concrete? A. Higher porosity; C. The weakest link in normal concrete D. Thickness comparable to the mean/average particle size of cementitious materials B. Containing less C-S-H: 5) All of the following procedures can improve the durability of concrete, except for: A. Entrap air voids in fresh concrete to enhance freeze/thaw damage resistance; B. Use fly ash/GGBS to absorb more chloride ions to retard chloride penetration; C. Use corrosion inhibitor to prevent steel from corrosion; D. Coat the external surface of concrete using polymeric latex. (6) In the following factors, which affects the INTRINSIC (not test results) strength of concrete? A. w/c; B. Aggregate type and volume fraction;

Explanation / Answer

1 c

2 A

3 B

4 F

5 b

6 f

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