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Would you expect a ready-mix concrete plant to produce concrete with a higher or lower coefficient of variability compared to a standard mix-on-site concrete?

A wall footing has the following conditions. Determine the required cross-sectional area of shrinkage and temperature reinforcement. Assume the footing is 4 ft wide, the pressure that acts on the bottom of the footing is 6,100 psf, and the reinforcement is a #9 bar spaced every 12 inches.The bottom of the footing is at a depth of 2 ft below grade.The service dead load is 11 kips/ft, and the service live load is 7 kips/ft.The wall is 10 in. thick.The footing is 11 in. thick.The allowable soil pressure, qa, is 5,100 psf.The soil has a density of 130 lb/ft3.The concrete has a density of 150 lb/ft3.The concrete cover has a thickness of 3 in.f’c = 3,600 psi and fy = 60,000 psi.

A well-graded aggregate mix increases the shrinkage in a concrete structure.

_______, commonly found in soils in the western US, can cause concrete to break down due to chemical attack.

Shrinkage is the decrease in the volume of concrete during hardening and drying under constant temperature.

The term “concrete strength” refers to the uniaxial _______ strength.

High strength concrete usually has a lower paste content.

There are no standards governing the quality of water for use in mixing concrete. In most cases, drinking water is not suitable.

The concrete in the core of a spiral column is subjected to a uniform confining stress σ3 of 220 psi. What will the compressive strength σ1 be? The unconfined uniaxial compressive strength is 3,600 psi.

Autogenous shrinkage occurs when moisture diffuses out of the concrete and the exterior shrinks more rapidly than the interior.