Use of the Nere Pod (Parkia Biglobosa) for the Improvement of Mechanical Properties of Soils

Abstract

Buildings made of unbaked clay have some advantage in terms of production cost. However, they have some inconveniences concerning their mechanical performance, particularly their resistance to weather. The objective of this study is to minimize these disadvantages and to maximize the benefits of such buildings to make them more viable. For this purpose, a method based on a traditional practice where the néré pod is utilized as a color wash, as well as, a binder is used. In the first case (color wash), it is to protect the building against weather damage, in the latter case, it is used to improve the mechanical performance of the coatings on the ground and it is in this way that rural people use to keep more sustainable homes. To achieve this, geotechnical characteristics were studied on seven (07) soil samples collected in seven (07) localities in Togo (Kovié, Aouda Zanguéra, Sarakawa Tagbamba, Goumoukopé and BB Lomé). The same geotechnical characteristics were studied on the same soil samples enhanced by adding the néré pods. Finally, a study was conducted to optimize the performance of this new composite material (soil-néré pod) based on the proportion of néré pod within the material. To manufacture a brick of dimensions of 22×14×9.5 cm, 8.5 kg of the mixture was needed and the amount of dampening water needed was equal to the amount of water to obtain optimum Proctor plus 2%. The results of these tests confirmed that néré pods help to improve the mechanical performance, especially the resistance to compression and puncture of the soils under consideration.