Affordable and Sustainable Housing in Rwanda
1.1. Shelled Compressed Earth Blocks
1.2. Earth Walls in Urban and Rural Areas
2. Materials and Methods
2.1. Muhanzi Clay Soil
2.2. Volcanic Aggregate (Amakoro), Musanze
2.3. Research Design/Analytical Approach
2.4. Mechanical Kit for Production of Laboratory Samples
2.5. Surface Resistance Test
3.1. Particle Size Distribution and Plasticity Index of Muhanzi Clay Soil
3.2. Particle Size Distribution of Volcanic Aggregate (Amakoro)
3.3. Optimum Moisture Content of Muhanzi Clay Soil
3.4. Results for the Shell of SCEB
3.4.1. Optimum Cement Content
3.4.2. Surface Resistance
3.4.3. Initial Rate of Water Absorption
3.4.4. Compressive Strength
3.5. Results for the Inner Core of SCEB
Optimum Aggregate Content
3.6. Summary of Results of Costs from Market Survey
4. Analysis of a Model Masonry Unit
5. Architectural and Building Opportunities
6. Compressed Earth Buildings in Rural Areas
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
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|Block||Composition||Block Thickness||Area of Wall Covered||Cement (kg)|
|Compressed Earth Block (CEB)||12% cement||200 mm solid||1 m2||43.5 kg|
|Durability/Exposure to weather||✔||✔|
|High surface resistance||✔|
|1. Conduct Particle Size Distribution of Earth and Amakoro. Design and Fabricate CEB/ shelled compressed earth blocks (SCEB) Kit||2. Establish Optimum Moisture content, Optimum Cement Content, and Optimum Aggregate Content||3. Analyze Cement Content and Weight of Hollow SCEB against Control||4. Architectural and Construction Opportunities of SCEB and OSCEB in Expanding the Limits in Earthen Architecture|
|Conduct particle size distribution of Muhanzi clay soil and musanze volcanic aggregate in accordance with BS EN ISO 17892-12:2018 .|
Design and fabricate CEB/SCEB mechanical kit .
|Produce laboratory test cube samples of compressed earth with same compaction pressure but varying moisture content and test for strength .|
Produce laboratory test samples of compressed earth with same compaction pressure but varying cement content and test for surface integrity, initial rate of water absorption, and compressive strength in accordance with BS EN 772-11:2011  and BS EN 772-1:2011 .
Make laboratory cubes of compressed earth with varying aggregate content; and test for strength and initial rate of water absorption.
|Calculate and assess the cement requirement per unit block.|
Calculate and assess weight reduction per unit block.
Calculate and assess cost reduction per square meter of wall, in comparison with other common wall materials.
|Analyze results of tests in comparison with conventional masonry units. Establish architectural implications and opportunities.|
|Masonry Type||Cost of Unit Block/Brick (rwf)||Number of Blocks in 1 m2 of Wall|
|Baked Brick (Industrial)||700||25|
|Shelled Compressed Earth (Calculated Material and Labor Costs)||180||38|
|Description of Items||CEB—Muhanzi Clay Soil||Model SCEB—Muhanzi Clay Soil|
|Volume of unit block (mm3)||Block||Void||Shell||Core||Void|
|Mass of unit block (g)||7445||0||1996||4589||0|
|Mass of cement required for unit block (g)||596||0||158||83||0|
|Total amount of cement required for unit block||596 g||241 g (60% reduction of cement)|
|Description of Item||CEB Muhanzi Clay Soil||SCEB with 33% of Volcanic Aggregate in Core|
|Mass of unit block (g)||Block||Void||Shell||Core||Void|
|Total mass of unit block||7445 g||6585 g (12% reduction in mass)|
|Cost Items||Sand-Cement Wall|
|Baked Brick Wall|
|Compressed Earth Wall|
|Shelled Compressed Earth Wall (SCEB) (Interlocking) (rwf)|
|Cost of blocks or bricks per 1 m2||7500|
(15 Blocks at 500 rwf per block
(25 blocks at 700 rwf per brick)
(38 blocks at 250 rwf per brick)
(38 blocks at 180 rwf per brick)
|Cost of mortar per 1 m2||3700||6400||1050||1050|
|Cost of Plastering||4500||NA||NA||NA|
|Painting (Basic emulsion)||1500||NA||NA||NA|
|Estimated Total Cost of 1 m2 Area of Wall||17,200 rwf|
(218% of SCEB)
(303% of SCEB)
(134% of SCEB)
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Egenti, C.; Khatib, J. Affordable and Sustainable Housing in Rwanda. Sustainability 2021, 13, 4188. https://doi.org/10.3390/su13084188
Egenti C, Khatib J. Affordable and Sustainable Housing in Rwanda. Sustainability. 2021; 13(8):4188. https://doi.org/10.3390/su13084188Chicago/Turabian Style
Egenti, Clement, and Jamal Khatib. 2021. "Affordable and Sustainable Housing in Rwanda" Sustainability 13, no. 8: 4188. https://doi.org/10.3390/su13084188