New green requirements have been established for vertical surfaces.
More people are choosing insulated concrete walls than wood frame walls in residential construction. Concrete homes can be constructed with insulating concrete forms (ICF), cast-in-place concrete, precast concrete panels, autoclaved aerated concrete, and concrete masonry. These construction methods generally lead to energy-efficient homes due to their thermal mass, high levels of insulation, and low air infiltration. But because of the low air infiltration, controlling moisture is important.
To prevent thermal cracking, most state departments of transportation cite a maximum temperature differential requirement for mass concrete in bridge piers. This requirement can create headaches for the contractor who hasn't fully considered how to deal with it. We asked Martha VanGeem, principal engineer with Construction Technology Laboratories (CTL) in Skokie, Ill., and Ralph Browne, bridge field engineer with the Texas Department of Transportation (TxDOT) Bridge Division in Austin to address this issue. In this discussion they tell us what can be done to provide improved and practical specifications for durable mass concrete construction.
