Eclipse shrinkage-reducing admixture

Eclipse is a liquid admixture for concrete (or virtually any portland cement-based material) that can reduce the material's drying shrinkage by up to 80% within the first 28 days and up to 50% after a year, according to its maker, Grace Construction Products. As a result, the finished concrete surface is less vulnerable to cracking, curling, and de-bonding, which extends its life and reduces maintenance.

Paul Kelley, principal with Simpson Gumpertz and Heger, recently specified Eclipse for an exposed polished concrete topping slab at a 50,000-sf industrial manufacturing building that is being converted into office space for SGH's Waltham, Mass., office. Kelley also specified the product for a bonded concrete overlay on the ground level of a 10-story, 180,000-sf college dormitory in the Boston area.

Why Paul Kelley specifies Eclipse

"This product offers multiple benefits to varied building problems by reducing cracking and curling of slabs-on-grade."

"The reduced shrinkage not only minimizes the risk of cracking and curling, but also reduces the bond-line stresses due to restraint of shrinkage and curling tendency, thereby reducing the risk of de-bonding of concrete overlays."

"Eclipse is particularly effective in appearance- or performance-critical applications such as exposed architectural floors, bonded overlays, and applications where cracks can adversely affect the performance of the structure."