Global Journal of Researches in Engineering, E: Civil & Structural, Volume 23 Issue 2

Stabilization of a Sub-Saharan Laterite Soil using Calcium Silicate Babacar LY α , Makhaly BA σ & Adama Dione ρ Abstract- The main objective of the research being conducted is, not only to achieve the required soil engineering properties by mixing this product but also to consider the effect of this product of soils stabilization on fine particles contained in lateritic and typically clayey soils. This research work presents the efficiency of calcium Silicate as an additive in improving the engineering characteristics of laterite aggregate soil and clayey soils. Investigations will be done to evaluate the effectiveness of this soil stabilizer which involved the use of calcium Silicate (CaSiO3) formula fixed by (Ndiaye et al, 2022). As a chemical additive the percentage of the binder will be respectively 4 and 6%. These two types of soils are expected to be stabilized and their effectiveness will be observed from the expected results only in terms of strength and consolidation by constant rate of strain parameters like recompression index (Cr) and compression index (Cc). The results of the tests conducted in Oregon State University on laterite aggregate soil showed that the compression strength (UCS) gives a value of 1,4 MPa for SH85 treated samples against 1,5 MPa for Portland cement ones but with a minimum of strain, under alternating temperature conditions. However, this evolution is even more important on clay samples, reaching 1.01 MPa of stress for ‘’dry black clay’’ against 0.44 MPa for the ‘’dried black clay’’ as peaks. The alternating wet and dried conditions were crucial as well as the specimens sizes. Keywords: soil stabilization, chemical additive, calcium silicate, unconfined compressive strength and consolidation by constant rate of strain. Author α σ : University of Thies-Laboratory of Mechanics and Modeling (L2M). e-mail: lyxbabs@yahoo.fr Author ρ : National School of Mines and Geology (ENMG). To fulfill the aim of this study, the following objectives have been framed. 1. To procure the 6% treated black clay soil with CaSiO3. 2. To procure the 4% treated laterite with CasiO3 and the 4% treated laterite with cement samples. 3. To procure the untreated black clay and the untreated red clay samples. 4. To study the results in term of UCS for laterite samples or in term of consolidation by CRS for the procured clayey samples. 5. To compare the performance of these soils when stabilized with Calcium silicate with the same soils when stabilized with Portland-cement. II. L itterature The Ngoundiane lateritic gravel borrow is located in the western part of the Senegal-Mauritania basin. The latter is the largest basin (340,000 km2) on the passive margin of Africa's Atlantic coast. It covers 3/4 of the surface area of Senegal. The western domain extends west from the 16° 30' W meridian to the slope of the continental slope, as the basement has not yet been reached by drilling. The Meso-Cenozoic sedimentary cover is estimated to be 8,000 m thick in Dakar and 10,000 m thick in Basse Casamance. The oldest known borehole deposits in southern Cape Verde date from the Bathonian to Callovian periods. On the Thiès plateau, the sedimentary series is masked by the fini-Neogene ferruginous cuirass, which extends northwards beneath Quaternary eolian deposits. This cuirass developed on the soils of the Thiès plateau after chemical alteration of the Eocene sediments (Flicoteaux, 1982; Ducasse et al, 1978). (Latifi et al., 2015) have conducted a study on a treated tropical laterite soil with calcium-based powder stabilizer (commercial name Sh85 we studied as performed to determine the strength performance of the treated soil. The strength test results showed that the Sh85 stabilized laterite soil was roughly five times stronger than the untreated soil at the seven days of curing period. III. M ethodology A dopted − Firstly, aggregate soil samples have been collected from Senegal 02 sites (Bambey and Thiadiaye) in © 2023 Global Journals Global Journal of Researches in Engineering ( ) E Volume XxXIII Issue II Version I 47 Year 2023 I. A im & O bjective of the W ork he present work is aimed at assessing the effects of Calcium Silicate (CaSiO3) in soil stabilization. - We will be conducting an unconfined compressive strength test (UCS) on the laterite aggregate treated either by CaSiO3 or by cement. − We will also be conducting a Consolidation by constant rate of strain (CRS) test on the black clay treated samples, untreated red clay and untreated black clay. The strengths of soils and their compression parameters will be observed and compared. T CaSiO3 ). A series of compressive strength tests was