Effects of Volcanic Tuff Use on the Rheological and Mechanical Properties of Self-Compacting Concrete

• Published in: DIYALA JOURNAL OF ENGINEERING SCIENCES Vol. 17; no. 3; pp. 78 - 97
• Main Authors: Musungu Khaoya, Lewin, Abuodha, Sylvester, Mwero, John Nyiro
• Format: Journal Article
• Language: English
• Published: University of Diyala 01.09.2024
• Subjects: Filling ability; Passing ability; Regression analysis; Segregation resistance
• ISSN: 1999-8716; 2616-6909
• DOI: 10.24237/djes.2024.17306

The rise in demand of concrete products has led to overexploitation of river sand the main fine aggregate in concrete resulting in major environmental degradation. As a result, researchers have focused their efforts on developing eco-friendly concrete using alternative renewable materials like volcanic tuff and other natural pozzolana types. This study therefore, aims at investigating the use of Kenyan, Kitengela volcanic tuff as a partial replacement of river sand in self-compacting concrete, and determining the effects it will have on the rheological and mechanical properties of the self-compacting concrete. The study involved partially replacing river sand with volcanic tuff in percentages of 0%, 2.5%, 5%, 7.5% and 10% and carrying out rheological tests (V-funnel test, L-box test, T-500 test and J-ring test) on fresh concrete and mechanical tests (compressive strength and tensile strength tests) on hardened self-compacting concrete on days 7, 14, and 28 to determine the effects of volcanic tuff on properties of both fresh and hardened self-compacting concrete. There was a general decrease in rheological properties (flow and passing abilities) of self-compacting concrete with increase in volcanic tuff percentage replacement from 0 % to 10%, with least flow and passing abilities recorded at 10% replacement.  Similarly, increase in volcanic tuff percentage replacement led to decrease in both compressive and tensile strength of self-compacting concrete with lowest values recorded at 10% volcanic tuff replacement.