Blog

A concrete cube is subjected to biaxial loading. Estimate the compressive strength σ1 if σ2 = 0.8 times the compressive strength, in compression.

The concrete containing Type I cement in a structure is cured for 5 days at 70°F, followed by 3 days at 72°F. Use the maturity concept to estimate its strength as a percentage of the 28-day strength under standard curing. Maturity is defined as M = Σ(Ti + 50)(ti) where Ti is in degrees F and ti is in days.

A group of 25 tests on a given type of concrete had a mean strength of 4,600 psi and a standard deviation of 400 psi. Does this concrete satisfy the strength requirement for 3,500 psi concrete?

The decrease in the volume of concrete during hardening and drying under constant temperature is called shrinkage.

A lower water/cement ratio reduces the porosity of the hardened concrete and thus increases the number of interlocking solids.

Bond cracks are microcracks that occur along the interface between paste and aggregate.

Which of the following is not a common durability problem in a concrete structure.

Fly ash may not even dramatically affect the final strength of concrete but can improve the _______.

There are no standards governing the quality of water for use in mixing concrete. In most cases, drinking water is suitable.

A group of 20 tests on a given type of concrete had a mean strength of 4,000 psi and a standard deviation of 800 psi. Does this concrete satisfy the strength requirement for 5,000 psi concrete?