Retaining Wall Block Durability Manchester CT

Source: CONCRETE PRODUCER MAGAZINE
Publication date: October 1, 2007

By CONCRETE PRODUCER Staff

Q: We have been trying to convince our local public works officials to specify segmental retaining wall (SRW) blocks on an upcoming project. We are located in the northern part of the United States. And the county's engineering staff is concerned that the SRW blocks will not be durable given our area's numerous freeze-thaw cycles and the heavy use of deicers on the roads and sidewalks.

While our SRW products have a good service life on many area projects, we have agreed to review our mix designs in search of even a better unit. Should we consider adding an air entrainment admixture to help prevent damage from frost or deicing salt scaling?

A: Although research and service-life assessments of existing structures have shown that using air entrainment in ordinary concrete can improve frost resistance and deicing scaling resistance, there is little agreement on how successful it works in dry concrete.

First, there's the question of whether the admixtures can even cause entrainment. Some studies have shown that air entrainment is extremely difficult, regardless of the admixture dosage rate. But other studies have reported some entrainment dependent on specific conditions of admixture type, mix design, plant mixer, and batching sequence.