Incorporación de ceniza de cáscara de maní como material cementante para el mejoramiento de la resistencia y durabilidad del hormigón

Abstract

The present experimental study aimed to analyze how the incorporation of peanut shell ash as a partial cement substitute contributes to the improvement of the compressive strength and durability of conventional concrete. For this study, replacement percentages of 1.5%, 2.0%, and 2.5% were evaluated and compared with a conventional concrete control mix, which was designed to achieve a compressive strength of 210 kg/cm². The ash was obtained from peanut shells collected in the city of Portoviejo, Manabí Province. The peanut shells were subjected to natural drying and controlled calcination between 400°C and 800°C in an artisanal furnace. Using the resulting ash and the corresponding aggregates, a total of 36 concrete cylinders were produced: 9 for conventional concrete and 27 for concrete modified with different ash percentages. These specimens were subjected to compressive strength tests at ages of 7, 14, and 28 days. Additionally, density, absorption, and permeable voids tests were performed on hardened concrete to evaluate the durability of both conventional and ash-modified concrete. The results showed that the mix containing 1.5% ash achieved the highest average compressive strength at 28 days, reaching 220.94 kg/cm², slightly exceeding the control mix, which recorded 219.24 kg/cm². On the other hand, the mix containing 2.5% ash presented the lowest average compressive strength, with 193.75 kg/cm². Regarding durability, the mixture with 1.5% ash obtained the best performance, presenting the lowest absorption percentage (3.31%) and permeable void content (8.20%). It was concluded that the incorporation of peanut shell ash in low and controlled percentages can maintain or slightly increase the mechanical properties of concrete due to the cementitious properties provided by the silica contained in this type of ash.