A BENCHMARK STUDY ON THE PERFORMANCE OF STABILIZED SOIL BLOCKS

ABSTRACT

The project aimed at conducting benchmarking to determine whether the performance of Stabilized Soil Blocks (SSBs) has been well-optimized by vendors who make the blocks after acquiring the block-making machines. The main concern was slow adoption of SSB technology despite the blocks being cheaper in an economy where there is high demand for low-cost housing for both urban and rural settlements. One of the possible reasons for the slow acceptance of the technology may be an assumption that the blocks have poor properties and hence lack of confidence in them. Therefore, the project aimed at testing the properties of SSBs available in the market and compare with (a) samples manufactured by one of the major vendors of the SSB machinery (e.g., Makiga Engineering Limited), samples of dimension and fired clay bricks – both of these are popular walling materials in the Kenyan housing construction sector. It focused on three parameters namely: compressive strength, density, and water absorption.

After the tests, it was discovered that actually, SSBs have the best properties compared to dimension stone and fired clay bricks. This is due to the compaction process that SSBs undergo. The project further led to the ranking of the properties of the blocks in terms of their densities, water absorption, and compressive strength. Generally, the Standard Interlocking SSBs topped the list in terms of compressive strength (9.2 MPa), followed by Wide Straight Interlocking SSBs (2.8 MPa) while the Dimensional Stone came third (2.6 MPa). The Clay Bricks came a distant fourth, and it had a very weak compressive strength of 0.2 MPa despite its popularity in the rural areas. Based on the densities, the Standard Interlocking SSB still topped the list (1900 kg/m3), followed by its Wide Straight counterpart (1863 kg/m3), and while the dimension stone (1547 kg /m3) and clay bricks (1488 kg /m3) emerged third and fourth respectively. However, there was a difference in performance in terms of the water absorption because the Wide Straight Interlocking SSB lead (10%), followed by Clay Bricks (10.8%), while Standard Interlocking SSB managed position three (16%). The dimension stone underperformed at position four (22%).