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

A wall footing has the following conditions. Determine the critical one-way shear, Vu, at a distance of d from the face of the wall. Assume the footing is 5 ft wide, the pressure that acts on the bottom of the footing is 5,680 psf, and the reinforcement is a #7 bar spaced every 12 inches.The bottom of the footing is at a depth of 2 ft below grade.The service dead load is 13 kips/ft, and the service live load is 8 kips/ft.The wall is 10 in. thick.The footing is 12 in. thick.The allowable soil pressure, qa, is 4,900 psf.The soil has a density of 120 lb/ft3.The concrete has a density of 150 lb/ft3.The concrete cover has a thickness of 3 in.f’c = 4,000 psi and fy = 60,000 psi.

The strength of concrete under biaxial compression is less than the uniaxial compressive strength.

A group of 20 tests on a given type of concrete had a mean strength of 4,800 psi and a standard deviation of 400 psi. Does this concrete satisfy the strength requirement for 4,500 psi concrete?

The standard compressive strength acceptance test is performed on concrete cylinders that are how old?

Prolonged moist curing leads to higher concrete strength.

This shrinkage occurs without the loss of moisture due to hydration reactions.

What does the “c” represent in f’c?

Drying shrinkage occurs in carbon-dioxide rich atmospheres.

The three most common durability problems in concrete structures are corrosion of steel in the concrete, breakdown of the structure of the concrete due to freezing and thawing, and breakdown of the structure of the concrete due to a chemical attack.