A longer yield plateau signifies a _______ brittle material.

A concrete cube is subjected to biaxial loading. Estimate the compressive strength σ1 if σ2 = 0.2 times the compressive strength, in compression.

High strength concrete usually has a higher paste content.

A wall footing has the following conditions. Determine the shear capacity, φVn, of the footing. Assume the footing is 4 ft wide, the pressure that acts on the bottom of the footing is 4,800 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 8 kips/ft, and the service live load is 6 kips/ft.The wall is 12 in. thick.The footing is 10 in. thick.The allowable soil pressure, qa, is 4,300 psf.The soil has a density of 110 lb/ft3.The concrete has a density of 150 lb/ft3.The concrete cover has a thickness of 3 in.f’c = 3,500 psi and fy = 60,000 psi.

A group of 30 tests on a given type of concrete had a mean strength of 4,000 psi and a standard deviation of 600 psi. Does this concrete satisfy the strength requirement for 3,000 psi concrete?

A concrete cube is subjected to biaxial loading. Estimate the compressive strength σ2 if σ1 = 0.5 times the tensile strength, in tension.

Concrete subjected to a sustained axial load greater than the critical load will eventually fail under that load. The critical stress is _______ fc’.

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

A shorter yield plateau signifies a _______ brittle material.

The concrete in the core of a spiral column is subjected to a uniform confining stress σ3 of 300 psi. What will the compressive strength σ1 be? The unconfined uniaxial compressive strength is 4,600 psi.