A group of 30 tests on a given type of concrete had a mean strength of 4,200 psi and a standard deviation of 800 psi. Does this concrete satisfy the strength requirement for 3,000 psi concrete?

The concrete in the core of a spiral column is subjected to a uniform confining stress σ3 of 750 psi. What will the compressive strength σ1 be? The unconfined uniaxial compressive strength is 4,300 psi.

Choose the equation that will give the largest factored load when D = 28 kip, L = 2 kip, Lr = 13 kip, and S = 20 kip.

Concrete is a mixture of water, cement, aggregate, and ______.

Creep tends to occur more in concrete mixtures with high _______ content.

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

The density of plain concrete is often assumed to be _____ lb/ft3.

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

A longer yield plateau signifies a _______ ductile material.

Concrete strength increases with age.