PhD Defence: Dr. Philbert Nshimiyinana - Influence of clay earthen and substitution materials on the durability of compressed earth blocks

Download the Dissertation Here

Philbert Nshimiyinana received the title of Doctor in Sciences and Technologies (Specialty Materials) on Monday, August 31, 2020, at Liège University in Belgium. His dissertation is titled "Effect of the type of clay earthen materials and substitution materials on the physico-mechanical properties and durability of compressed earth blocks". This thesis was co-supervised by Luc Courard Professor at ULiege (UEE-GeMMe) in Belgium and Adamah Messan Professor at the Construction Materials Laboratory and the 2iE Institute in Burkina Faso through the Eco-Materials and Sustainable Habitats Laboratory (LEMHaD). At least six key papers were published as part of his Ph.D.:

• Nshimiyimana P, Fagel N, Messan A, Wetshondo, D O, Courard, L (2020) Physico-chemical and mineralogical characterization of clay materials suitable for production of stabilized compressed earth blocks. Constr Build Mater 241:1–13. https://doi.org/10.1016/j.conbuildmat.2020.118097.
• Nshimiyimana P., Messan A., Courard L. (under review) Physico-mechanical and hydrothermal properties of compressed earth blocks stabilized with industrial and agro by-products: Calcium carbide residue and rice husk ash
• Nshimiyimana P, Moussa HS, Messan A, Courard L (2020) Effect of production and curing conditions on the performance of stabilized compressed earth blocks: Kaolinite vs quartz-rich earthen material. MRS Adv 1–7. https://doi.org/10.1557/adv.2020.155.
• Nshimiyimana P, Hema C, Zoungrana O, Messan A, Courard L (under review) Thermophysical and mechanical properties of compressed earth blocks containing fibres: by product of okra plant & polymer waste
• Nshimiyimana P, Moussa HS, Messan A, Courard L (2020) Effect of production and curing conditions on the performance of stabilized compressed earth blocks: Kaolinite vs quartz-rich earthen material. MRS Adv 1–7. https://doi.org/10.1557/adv.2020.155.
• Nshimiyimana P, Messan A, Zhao Z, Courard L. (2019) Chemico-microstructural changes in earthen building materials containing calcium carbide residue and rice husk ash. Constr Buil Mat. 216C:622–631. https://doi.org/10.1016/j.conbuildmat.2019.05.037
• Moussa HS, Nshimiyimana P, Hema C, Zoungrana O, Messan A, Courard L (2019) Comparative Study of Thermal Comfort Induced from Masonry Made of Stabilized Compressed Earth Block vs Conventional Cementitious Material. J Miner Mater Charact Eng 07:385–403. https://doi.org/10.4236/jmmce.2019.76026
• Nshimiyimana P., Miraucourt D., Messan A., Courard L. (2018) “Calcium Carbide Residue and Rice Husk Ash for improving the Compressive Strength of Compressed Earth Blocks”, MRS Adv. 3(34-35)2009-2014. https://dx.doi.org/10.1557/adv.2018.147

Dissertation Abstract: Clay earthen materials are the most common building materials used all over the world for sustainable constructions. Today, the drastic increase of population and urbanization, especially in the developing world, calls for better knowledge of earthen materials in contemporary construction. The present thesis aimed to characterize the suitability of clay materials from four sites in the vicinity of Ouagadougou, Burkina Faso: Kamboinse, Pabre, Kossodo, and Saaba for the production of stabilized compressed earth blocks (CEBs). The study also characterized by-products of industry: calcium carbide residue (CCR) from Kossodo and agriculture: rice husk ash (RHA) from Bagré and Okra plant fibers from Kaya for the stabilization of CEBs. The characterizations were carried out on physico-textural and chemico-mineral properties. The study additionally tested the physico-mechanical, hygro-thermal, and durability performances of CEBs stabilized with the by-products for applications in building construction, specifically for applications in the Sahelian climatic context. Mixtures were produced by addition of 0-25 wt% CCR, 10-25 wt% CCR:RHA (various ratios), and 0.2-1.2 wt% fibers to the earthen materials. The mixtures were used to produce the mix solutions and mold stabilized CEBs (295x140x95 mm3) by static compression (~35 bars) and cured in various conditions for 0 to 90 days. The results show that the clay materials from Pabre and Kossodo respectively contain the highest fraction of clay particles (20-30%) and gravel (40%). Saaba and Pabre respectively contain the highest fraction of kaolinite clay mineral (60-80%) and quartz (40-60%). Kamboinse contains the highest amount of exploitable deposit (700 000 m3), 10-25% clay particles, and 40-75% kaolinite, while Kossodo contains a medium fraction of kaolinite (35-50%). The CCR mainly contains portlandite (40-50 % hydrated lime: Ca(OH)2). The RHA is mainly amorphous, with pozzolanic reactivity. Saaba and Kossodo recorded the highest rate of pozzolanic reactivity with CCR, related to the high content and degree of poorly ordered kaolinite. Pabre and Kamboinse recorded the lowest rate of reactivity. With respect to unstabilized CEBs (0 % CCR), the compressive strength of CEBs stabilized with 20% CCR cured at 40±2°C for 45 days produced with the clay material from Saaba improved tenfold (0.8 to 8.3 MPa) compared to Kamboinse (1.1 to 4.7 MPa), Pabre (2 to 7.1 MPa) and Kossodo (1.4 to 6.4 MPa). All clay materials are suitable for the production of stabilized CEBs with compressive strength of 4 MPa. Furthermore, the stabilization of the earthen material from Kamboinse using novel binders improved the structural efficiency of CEBs cured in ambient conditions of the lab (35±5°C): increase of compressive strength and decrease of bulk density. It also improved the hygro-thermal efficiency: decrease of thermal effusivity, conductivity and diffusivity and increase of thermal specific capacity and water vapor sorption. The CEBs stabilized with at least 10 % CCR or 18-2 to 16:4 % CCR:RHA satisfy engineering requirements and durability for the construction of two or three storey buildings. Therefore, the selection of earthen materials should take into account the reactivity with the stabilizer.

Keywords: calcium carbide residue; compressed earth block; durability; kaolinite clay; microstructure; pozzolanic reactivity; physico-mechanical property, rice husk ash.

Download the Dissertation Here

Ever thought about using Okra, known as gumbo or ladies' fingers, as a bio-sourced binder for load-bearing walls or compressed clay earthen blocks (CEB)?

Dr.Philbert Nshimiyinana tried to answer this question. The Ph.D. entitled 'Effect of the type of clay earthen materials and substitution materials on the physico-mechanical properties and durability of compressed earth blocks' is available online in the post. Congratulations to Dr. Philbert Nshimiyinana who successfully defended his Ph.D. thesis at Liege University co-supervised by prof. @Luc Courard Professor at ULiege in Belgium and prof. @Adamah Messan Professor the 2iE Institute in Burkina Faso. All the best Philibert for your future career.