Open Collections

Alasvand Zarasvand, Kianoush

University of British Columbia

The traditional rammed earth (RE) construction is currently regaining popularity in North America for several reasons: low maintenance cost, high energy efficiency, locally available raw materials, low CO₂ emissions, and better recyclability (Ávila et al., 2022). Previous studies have proved that the strength and durability of RE can be further improved by adding cementitious materials such as Portland cement, fly ash, natural and synthetic fibers, and steel slag. However, no significant research has been conducted to evaluate the thermal behavior of these modified RE materials. In this study, the effect of chemical additives such as cement, wood fly ash, and calcium bentonite on the thermal properties of rammed earth (RE) material is evaluated to assess the viability in hot and cold climates. Compacted and cured hollow RE samples were used for measuring the decrement factor, time lag, and peak temperature. An environmental chamber was used throughout this study to cure the RE specimens under simulated weather conditions. A hot climate, with 40% and 80% humidity and temperature that decreases from 45°c to 27°c with a uniform slope, and a cold climate, with a humidity of 40% and temperature that increases from -7°c to 12°c with a uniform slope, were simulated. Also, thermal conductivity and specific heat capacity are evaluated using a heat flow meters (Fox 50). While the partial replacement of Cement in RE with fly ash improved the thermal properties of the material in both hot and cold climates, incorporating 15% Calcium bentonite in the mix design further enhanced the thermal efficiency of RE in cold climates. Also, the thermal conductivity tests have shown that substituting a significant fraction of Cement in RE with wood fly ash can improve the thermal conductivity by up to 20%. Hence, the results of this study indicate that the wood ash-stabilized rammed earth is suitable for construction in colder climates.

Text; Still Image

2023-08-30

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/82663

Civil Engineering

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/