A Sustainable Approach Using Beef and Pig Bone Waste as a Cement Replacement to Produce Concrete

Abstract

Owing to the ongoing accumulation of industrial by-products, the management and disposal of waste have emerged as a significant issue. Employing these industrial wastes as an alternative to replace cement holds potential as a promising solution for conserving energy and reducing CO2 emissions. In this study, pig and beef bone powder were used as cement replacements in concrete, and the mechanical properties were studied. Bone powders were prepared from random bones collected from local slaughterhouses, butchers, and restaurants. The pig bone powder (PBP) and beef bone powder (BBP) were prepared by direct fire contact, oven-calcined for 4 h at 300 °C, crushed, and sieved to size 0.4 to 2 mm. A concrete mix design was formulated for a target compressive strength of 21 MPa at 28 days of curing. This design included three different levels of cement replacement with each type of bone powder (10%, 15%, and 20% by mass). These mixes were then evaluated and compared to a control mix without any bone powder replacement (PB-0). This study evaluated the mechanical properties via compressive strength and flexural testing. The results showed that the workability of the mixtures decreased with the increase in bone powder content. Bone powder functions as a pozzolanic substance, engaging in a chemical reaction with the calcium hydroxide in concrete to produce compounds that exhibit cement-like properties; however, an increase in bone powder content worsened the mechanical properties. The most promising results were obtained for a 10% replacement percentage of BBP and PBP, obtaining strengths of 21.15 MPa and 22.78 MPa, respectively. These are both above the design strength, with PBP concrete even exceeding the strength of PB-0 (21.75 MPa). These results showed a good agreement with the standard values and allow to use these wastes as a replacement for cement, becoming a sustainable solution to the exploitation of quarry materials and, in turn, to the problem of contamination by biological waste from the meat industry.