What is type G concrete?
Type G is a type of shrinkage-compensating concrete that is used:
(1) to compensate for volume decrease due to drying shrinkage,
(2) to induce tensile stress in reinforcement, and
(3) to stabilize long-term dimensions of post-tensioned concrete structures.
One of the major advantages of using expansive cement is in the control and reduction of drying-shrinkage cracks. In recent years, shrinkage-compensating concrete has been of particular interest in bridge deck construction, where crack development must be minimized."
(Other expansive concretes do exist but are largely unavailable to the United States due to cost.)
Better Than Type K?
Expansive Concrete is the term used for a concrete mix that is designed to reduce or eliminate cracks and curling due to dry shrinkage.
You may have heard of type K concrete and in more recent years, type G. These classes of concrete are designed to create a stronger slab and reduce or eliminate cracking due to dry shrinkage.
Here is a comparison of the two types:
Expansion curve by percentage of Type G expansive component in the mixture:
(courtesy of Green Umbrella Systems™)