Development of new pH-adjusted fluorogypsum-cement-fly ash blends: Preliminary investigation of strength and durability properties

This paper develops a new low-cost construction material made of pH-adjusted fluorogypsum, class C fly ash, and type II Portland cement. The proposed fluorogypsum-based blend is durable in water and has a lower weight and lower cost than ordinary concrete. A preliminary investigation of strength and durability properties of this new construction material is also presented. A series of compressive strength tests and volumetric expansion measurements were conducted on specimens after 28 days of curing. The experimental results were used to develop response surface models. These models can be used to predict accurately compressive strength and volumetric expansion as functions of the relative content, in dry weight, of different components. The response surface models were employed to determine ranges of dry components of the system with sufficient strength and limited volumetric expansion. A composition with 62% pH-adjusted fluorogypsum, 35% fly ash, and 3% Portland cement was selected based on strength and volumetric expansion properties to conduct additional experimental studies to quantify its modulus of elasticity, Poisson's ratio, setting times, density, void contents, and curing time effects on strength and volumetric expansion. The investigation results suggest that the proposed fluorogypsum-based blend is a promising low-cost concrete-like material for use in outdoor and underwater construction applications.