(8) It is known that the compressive strength of a concrete is 40 MPa. In a tri-
ID: 1732830 • Letter: #
Question
(8) It is known that the compressive strength of a concrete is 40 MPa. In a tri-axial compression test, a constant lateral pressure of 15 MPa is applied on a cylindrical specimen prepared with this concrete. Estimate the result of this tri-axial test: A. 40 MPa C. 90 MPa B. 75 MPa; D. >100 MPa. (9) Diffusion of chloride ions in concrete cover towards steel reinforcements A. affects the service life of concrete structure in marine environments; B. is driven by chloride concentration gradient, the same as the driven force of permeation C. can be retarded by making concrete denser; E. (A&B;); D. All of above; F. (A&C;); G. (B&C;) (10) Drying shrinkage A. is caused by moisture migration; B. doesn't occur when the concrete is cured at 295% rh C. could cause tensile stress in the surface layer of concrete; D. All of above; E. (A&B;) F. (A&C;) (11) What is the Achilles' heel of reinforced concrete structure A. Steel reinforcement that can be corroded in air B. Capillary pores (and micro-cracks) through which matters can migrate C. Reactive aggregate that can react with alkali to form expansible gel D. Steel reinforced concrete is a perfect design without Achilles' heel. (12) Which of the following approaches can protect steel reinforcement from corrosion in Missouri? A. Electrochemical Cl extraction; B. Electrochemical re-alkalization C. Increase concrete cover thickness; D. Use epoxy coated rebar E. All of above; F. (C&D;).Explanation / Answer
8. A since the test is to find the compressive strength.
9. F
10.F
11. C
12. F That is C and D are correct.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.