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Development of agro-wastes based unfired earth blocks to improve indoor thermal comfort in tropics

Jannat, N (2023) Development of agro-wastes based unfired earth blocks to improve indoor thermal comfort in tropics. Doctoral thesis, Liverpool John Moores University.

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This research aims to develop agro-waste based unfired earth blocks that are suitable for tropical climate. The samples were produced using eggshell (10, 20, 30, 40, and 50wt.%), sawdust (2.5, 5, 7.5, and 10wt.%), coconut husk (2.5, 5, 7.5, and 10wt.%), and walnut shell (5, 10, 15, and 20wt.%) separately and in combination. In this study, several physico-mechanical, durability, and thermal properties tests were conducted. Moreover, numerical computer simulation analyses on the thermal performance of the developed materials were performed. Additionally, the effect of three different particle sizes of sawdust (212 μm ‹ x ‹ 300 μm, 425 μm ‹ x ‹ 600 μm, and 1.18 mm ‹ x ‹ 2.00 mm) was investigated. The results of physico-mechanical properties tests showed that the density of the samples gradually decreased with increasing agro-wastes percentages in the mixture. Besides, eggshell and walnut shell addition reduced the linear shrinkage and capillary water absorption, whereas finer sawdust particles and coconut husk incorporation increased both. The individual inclusion of eggshell, sawdust, and coconut husk improved the strength of clay blocks; however, walnut shell had a negative impact on the strength. On the other hand, combining eggshell with other agro-wastes did not contribute to improving the strength. The highest compressive strength (CS) and flexural strength (FS) of air-dried samples were obtained when 40% eggshell (CS: 5.68 MPa, FS: 2.24 MPa), 2.5% coconut husk (CS: 4.78 MPa, FS: 2.14 MPa), and 2.5% sawdust (CS: 4.74 MPa, FS: 2.00 MPa) were individually used. The compressive strength of eggshell, coconut husk, and sawdust samples improved by around 40%, 18%, and 17%, respectively, while the flexural strength enhanced about 47%, 41%, and 32% over the reference sample. The investigation of durability tests revealed that when agro-wastes were added, erosion resistance improved compared to the reference sample. According to the thermal properties tests, thermal conductivity and volumetric heat capacity decreased with the addition of agro-wastes. The lowest conductivity was obtained for the 10% coconut husk sample (0.172 W/mK), followed by the 10% sawdust (0.185 W/mK) and the 50% eggshell (0.299 W/mK) samples. Furthermore, in the wall scale test, the sample walls made of coconut husk, sawdust, and eggshell outperformed the reference sample wall in terms of thermal resistance, with improvements of around 48%, 35%, and 16%, respectively. This result was also supported by the numerical thermal simulation analyses, where the findings showed that coconut husk wall construction had a relatively lower (14.90 MWh) yearly energy consumption than sawdust (15.10 MWh), eggshell (17.70 MWh), and reference (18.90 MWh) walls. The overall findings of this study suggest that the incorporation of agro-wastes into clay blocks improved their properties, making them suitable for use as building construction material.

Item Type: Thesis (Doctoral)
Uncontrolled Keywords: Agro-wastes; Unired clay blocks; Physico-mechanical properties; Durability properties; Thermal properties; Tropics
Subjects: T Technology > T Technology (General)
T Technology > TA Engineering (General). Civil engineering (General)
T Technology > TD Environmental technology. Sanitary engineering
T Technology > TH Building construction
Divisions: Civil Engineering & Built Environment
SWORD Depositor: A Symplectic
Date Deposited: 10 May 2023 09:07
Last Modified: 10 May 2023 09:09
DOI or ID number: 10.24377/LJMU.t.00019427
Supervisors: Latif Al-Mufti, R, Abdullah, B, Cotgrave, A and Hussien, A
URI: https://researchonline.ljmu.ac.uk/id/eprint/19427
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