Sugar cane molasses has proved cohesive and excellent performance on soil aggregates (fine particles). However, the microstructure of consolidated soil by the molasses is not yet subjected to research. The analysis results of sample without molasses (0%) and consolidated samples at 8%, 12%, and 16% show that the molasses acts on the structure of clayey fine soil developing its microstructure of airy matrix type (sample without molasses (0%) to a microstructure of a qualified type, more solid. Consolidated samples to 8%, 12%, 16% of molasses). We also observe the presence of inter-aggregate pores (mesopores) of similar size in all samples. The results of porosimetrical analyses (BJH) of the sample without molasses and consolidated samples to 8%, 12%, and 16% show that simultaneous porous volumes of samples are reduced with the increasing of molasses quantity. This latter, therefore, acts on the porous volume (micropore < 2 nm and mesopore < 9 nm) by reducing them which really means, molasses occupies the porous volume of the sample. However, this sample seems not to have any effect on the size of mesopores 9 nm. Thus, this product induces the evolution of the soil structure towards the highly dense and condensed structure. Consequently, materials in consolidated soil by molasses will have mechanical properties far superior to those of materials consolidated soil without molasses.

This work presents a theoretical study based on the instability of fine soils stabilized with sugar cane molasses. Indeed, this stabilization is only effective during the dry season in the town of Nkayi due to the scarcity or non-existence of rainfall. This being the case, let us suppose that humidification influences the intrinsic parameters of the earth materials (suction, porosity) and even the stabilization capacity of the molasses, we can try to understand the instability phenomenon that occurs within the structural matrix of the material when it is solicited during periods of heavy rainfall. The current models which study the deformation of the proposed fine soils, relate the interaggregate voids, the intra-aggregate voids, the stability index, the suction of the soil material and the relative humidity of the environment. Also, the theoretical study of these models shows that the inter-aggregate voids increase with relative humidity, the intra-aggregate voids decrease with increasing relative humidity and the stability index decreases with increasing relative humidity.Similarly, inter-aggregate voids decrease with increasing suction, intra-aggregate voids increase with suction and the stability index increases with suction.However, with the extension of Ferber's model, the breaking point of the earth material is obtained using these same models, i.e. this minimum point beyond which the adhesion forces in the aggregate and between the aggregates become low to ensure cohesion between the aggregates in the material for a long time. All in all, this point is significant for Pr ( r H =35.768%, iag e =0.5262, ag e =0.078, ag e S = 0.0005 262), and S=146 MPa (suction value) and is defined as the breaking point below which the cohesion of the aggregates is not evident. This proposed model mathematically translates both the effects of relative humidity and suction on voids in earth materials. It also explains the deformations that take place in earth materials at the microstructure level (intra-aggregate voids and inter-aggregate voids) under the effect of moisture or suction.

Sugar cane molasses is often poured out on roads with soil in the city of Nkayi, Republic of Congo in order to reduce the dust. Nitrogen physical adsorption has allowed us to collect information on the state of the accessible total area according to the quantity of sugar cane molasses. The adsorption isotherms, the specific area, the adsorbed quantity of nitrogen on a Qm mono layer, the number of molecules constituting the adsorbed sugar cane molasses (n′) have been examined. The obtained results show that the quantity of sugar cane molasses in the material does not modify the adsorption isotherm of nitrogen of type IV that remains and a hysteria loop of type H4 in all samples, this justifies the monocoat-multicoat adsorption mechanism with capillary condensation and mesopores presence in the structure of materials. Materials with elaborated raw soil by clayey fine soil used are mesoporous materials. More of 50×10 18 molecules constituting sugar cane molasses occupy the extreme area accessible to soil clay, without occupying on accessible sites.