Concrete Products

MAR 2018

Concrete Products covers the issues that attract producers of ready mixed and manufactured concrete focusing on equipment and material technology, market development and management topics.

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60 • March 2018 Focusing on the compound at the heart of quality concrete, BASF Construction Chemicals has developed a first-of-its-kind liquid admix- ture that improves early- and late-age strength development. Master X-Seed 55 is a stable suspension of synthetically produced crystalline calcium silicate hydrate (CSH) nanoparticles that facilitate growth of CSH crystals between cement grains and improve overall portland cement hydration. "Given the X-Seed technology's widespread success in Europe since its 2009 launch, we worked to develop a unique formula specifically designed for North America," said BASF Admixture Systems Prod- uct Manager Chris Eagon during a World of Concrete 2018 product unveiling. "Master X-Seed 55 admixture utilizes CSH nanoparticles, along with other technologies, to facilitate and improve strength development at all ages of the concrete." Dosed at up to 10 oz./100 cwt, he added, the admixture allows ready mixed and precast concrete producers to expand the performance space of a given mixture—conventional slump to self-consolidating— and optimize the cementitious material content. Master X-Seed 55 likewise provides a strength safety factor, permits earlier stripping of forms to improve production efficiency, and promotes sustain- able construction by enabling higher than normal levels of portland cement replacement. Testing concretes prepared with total cementitious material content of 611 lbs./yd. at 0.47 w/cm, BASF engineers noted respective 1-, 7- and 28-day compressive strength gains of 46 percent, 18 percent and 19 percent for X-Seed 55-dosed specimens against controls. Companion tests gauging compressive strength development at the three intervals demon- strated the admixture's potential to offset total binder requirements by 10 percent. — BASF Construction Chemicals, Admixture Systems, Cleveland, 800/628-9990; INNOVATIONS MATERIALS BASF agent propagates CSH crystals to increase early, late-age strength BASF chemists illustrate the new admixture's effect on concrete by comparing the CSH crystal characteristics of typical hydrated cement grains (left) and those where Master X-Seed 55 nanoparticles tighten a matrix by compounding crystal formation. A scanning electron micrograph of a Master X-Seed 55-dosed paste sample evidences elevated calcium silicate hydrate crystal growth be- tween portland cement grains. Added crystal formation advances strength development at all ages of the concrete.

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