Use of pumice stone to elaborate ultra-lightweight concrete with controlled low strength

Abstract

This paper presents the results of premixed lightweight concrete mixtures using pumice stone as an alternative for the construction industry in Nicaragua. These special concretes generally use expanded vermiculite as a raw material. However, due to the difficulty in acquiring it on the local market, the use of pumice stone as an alternative material is proposed. The pumice was characterized and the maximum nominal aggregate size was determined, considering the final thickness of the slab. HE cements, drinking water, fine pumice aggregate, and industrial sand (zero material) were used. A liquid additive was used as a foaming agent to increase the presence of air and reduce density, a type D additive was used as a concrete setting controller, and a type F additive was used as a high-range water reducer. The results obtained show that the combination and proportion of the materials produced fresh concrete that could be placed with a telescopic pump and had mechanical properties in the hardened state in accordance with the design requirements.