Effect of Glass Powder and Egg Shell Powder on the Consistency and Setting Time of Cement Blends

Abstract

One alternative to the improper waste disposal and the high energy intensiveness of cement production is the use of cementitious materials such as eggshell (ESP) and glass powder (GP) as a partial cement replacement material. This paper investigates the effect of partially replacing ordinary Portland cement (OPC) with ESP and GP on the water consistency and setting times of cement blends (OPC-ESP-GP) up to 25 wt% replacement at interval of 2.5 wt%. Vicat apparatus was employed in the determination of the standard consistencies and setting times of cement blends at various proportions. Results indicated a variation in both setting times for cement replacement from 2.5 to 12.5 wt% except for 7.5 wt% which experienced a retardation, whereas beyond 12.5 wt% cement replacements led to an increase in the initial setting time as GP was replaced with ESP. This variation could be attributed to lime presence in ESP resulting in accelerated hydration rate despite clinker diminution and Magnesium hydroxide Mg(OH)2 low solubility resulting in the formation of a protective layer which retards cement hydration respectively. The water consistency diminished as ESP was replaced with GP for various cement replacement except 2.5 wt% which was attributed to the wider particle size distribution and vice versa. The blended cement’ consistencies were higher than OPC by 6.67–21.50% which was due to either clinker diminution or the high silica content and enhanced surface area of GP. The consistency and the setting times of the various cement blends satisfied the required standard.