Low-Heat-Performance Concrete (LHPC)
May 4, 2021 to May 4, 2021
1 PM EST
2 PM EST
Specifications for mass concrete require explicit planning and control of thermal stresses. Historically, overdesign of high-performance concrete for compressive strength through usage of excessively high portland cement contents has caused varying degrees of early age cracking due to both thermal and autogenous shrinkage stresses. Development of low-heat-performance concrete (LHPC) to minimize cracking and improve service life is a new approach that addresses concerns for cracking and service life through optimization. A properly designed LHPC can ease thermal control requirements and save time in the schedule, as well as provide a higher level of durability to owners. Design of LHPC requires minimization of cementitious materials content, optimization of supplementary cementing materials (SCMs), uniform gradation of aggregates, and selection of advanced admixture technology. A performance engineering approach incorporates durability in addition to early strength and constructability requirements to meet contractor needs. Performance requirements can include restrained shrinkage cracking resistance, linear free shrinkage limits, freeze-thaw resistance, alkali-silica reactivity, and chloride penetration resistance. Field performance to date has indicated that LHPC will provide owners with an increase in service life while meeting mass concrete specification requirements.
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