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

Figure 2: Evolution of the UCS of two (02) black clay specimens under different conditions The analysis of the curve shows us a progressive evolution of the UCS of two (02) black clay specimens. The ‘’dried black clay’’ represents the specimen treated by 6% of CaSiO3 and after 14 days normal curing to which we added 2 days (24H in wet at 25*C and 24H in dry at 110*C). The ‘’dry black clay’’ curve represents the specimen treated by 6% of CaSiO3 and keeped in a dry conditions at 25*C during the same timing. However, this evolution is even more important reaching 1.01 MPa of stress for ‘’dry black clay’’ against 0.44 MPa for the ‘’dried black clay’’ as peaks. The black clay is a swelling material, consequently, its expansion in the presence of water weakens it and makes it unfit for construction (figure 2). The original swelling mechanisms of soils have been widely studied, but it is still difficult to establish a relationship between the progression of the issue and the time (Cisse and al., 2017). Figure 3: Water content per type of specimen (laterite 4% CaSiO3, laterite 4% cement and black clay 6% CaSiO3) Alternating temperature between the wet environment at 25*C and the dried one at 110*C oven , during 2 cycles, showed the tendency of laterite samples treated with cement to absorb more water than those treated by calcium silicate (figure 3). 0.0 0.2 0.4 0.6 0.8 1.0 1.2 0% 5% 10% 15% 20% Vertical Stress (MPa) Axial Strain (%) dry black clay - 6% treated - 16 days curing dried black clay - 6% treated -14+2days (from 25*c to 110*C) 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 water content in % 1 Cycling = 24H wet-24H dry (at 60 to 110* C) lat Sh-%wc lat cem-%wc Black clay %wc © 2023 Global Journals Global Journal of Researches in Engineering ( ) E Volume XxXIII Issue II Version I 49 Year 2023 Stabilization of a Sub-Saharan Laterite Soil using Calcium Silicate