Journal of Sustainable Construction Materials and Technologies (Mar 2023)
Use of pumice aggregate in cementitious rheoplastic lightweight concrete
Abstract
Rheoplastic lightweight concrete (RLC) is generally designed for pumping applications as fluid concrete free from segregation. Concrete is produced using polymeric admixtures to enhance concrete workability, strength, drying shrinkage and durability. This research was studied to investigate suitability of natural porous pumice aggregates in Turkey to obtain rheoplastic lightweight concrete with cement content in normal ranges. To produce and experience rheoplastic concrete mix design data, rheoplastic lightweight concrete mixes were tested with fine pumice aggregate (FPA) and coarse pumice aggregate (CPA) supplied from Nevşehir region of Turkey. For rheoplastic lightweight concrete with cement contents in the 250 to 400 kg/m3 range, the percentage of fine pumice aggregates required was in the 73.6-81.0% range with free water/cement ratios of between 0.53 and 0.68. Upper compressive strength limit was circa 30 N/mm2. From the research findings, it was determined that the rheoplastic concrete samples with pumice aggregate met the design requirement as slump value of 200 mm for fresh concrete predicted for fluid concrete forms. While technical properties of hardened concrete such as oven dry density, strength values, static elasticity modulus, thermal expansion coefficient and thermal conductivity value decrease with increasing aggregate/cement ratios, they increase with increasing cement dosage. In addition, presence of high amount of fine pumice in concrete composition results in lower drying shrinkage and wetting expansion with decreasing cement dosage. The technical findings showed that RLC might be produced by using superplasticizer and air-entraining admixtures and mixtures of different sizes of pumice aggregates.
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