**4. Discussions**

Molasses have several potential uses in engineering applications due to aspects that give it advantages over conventional materials: it is soluble in water and without toxic components, an organic waste material derived from the food industry. Moreover, it is an inexpensive product, easy to acquire and with low dosages addition high maximum resistances can be achieved. For soil stabilization [44], If it is dosed at 2% by dry weight of soil, approximately 20 kg of molasses would be enough to process 1 ton of wet soil.

Saeed et al. [45] studied a kaolin with similar characteristics and engineering properties, treating it with different amounts of cement and curing times. The soil treated with 10% cement and cured for 28 days reached 2.10 MPa in unconfined compressive strength test. Approximately 100 kg of cement were necessary to process 1 ton of wet soil. Despite the research undertaken by Saeed et al. [45] and this work are not strictly equal, they can be compared on the bases of material costs for ground stabilization. In Colombia, molasses costs an average \$0.35 USD/kg and cement costs an average \$0.17 USD/kg. If 1 ton of soil is treated using cement, the costs would be approximately \$17 USD; while if the same amount of soil is treated using molasses the cost would be about \$7 USD. Although molasses is an inexpensive material when compared to cement, both as additives to soil, cement is a very competitive material when durability and strength are evaluated. Saeed et al. [45] concluded that 2% of molasses in dry soil matches the compression strength of soil with 10% cement, which is quite an impressive value. The durability on the other hand could be a limitation, as explained before, molasses changes very rapidly with time when compared with cement, although very little is known on this subject, therefore being a good area for research. Durability performance was not studied in this research, and it is possible that molasses does not provide the same durability as cement. However, soil improvement using molasses can be a temporal engineering solution.

Molasses are an organic material that suffers environmental degradation and aging. Therefore, the formulations properties of samples could be significantly affected. Research regarding the molasses stability in the soil have not been conducted yet, although future stability and chemical treatments for overcoming this issue are interesting as future research. Although biological activity was detected, a future systematic study will be conducted on the property's evolution and potential treatments as a function of the microorganisms' growth during the process. The samples were made under controlled fabrication procedure in this research, and the mechanical stability of the samples suggests that samples did not change significantly in a month, mainly because samples were made in a controlled environment, with constant atmosphere conditions. Regarding other construction applications under more severe conditions of temperature and load, the molasses have shown good stability [46] with load and temperature, but poor performance with moisture. Thus, to decrease the aging effect, for now, molasses has to be ideally at constant humidity. The clay used in this research in fact is a perfect material to keep the molasses isolated from water, to seal the soil as other clays [47], which is expected to decrease its natural and working-derived aging effects.

The Ministry of Transport in Colombia classifies tertiary roads as the routes that connect municipalities with rural municipalities [48]. Colombia has 142,284 km tertiary roads, of which 34,148 km do not have any engineering treatment [49]. Some of the aforementioned roads become impassable during the rainy seasons and thus soil improvement is required. Commonly, tertiary roads are stabilized using lime, cement, or a coarse aggregate structure. The analysis of behavior of the soils stabilized using molasses and its environmental impact is an environmentally friendly solution for ground improvement. This could reduce or replace the amount of cement used in tertiary roads, thus, reducing polluting gases generated by cement production. Clearly, this is not only a problem of Colombia, but also an issue in many developing countries.

There is a correlation in agglomerates between the liquid saturation and the growth rate of the agglomerates [50]. Interparticle forces are responsible for the formation of the agglomerates by attaching individual particles to each other [50]. The crushed soil in natural conditions mixed with water and 35% water content, has an average 3.12 mm diameter grain-size. Grain-size and its statistic data dispersion increase as molasses content increases. This occurs as the soil particles are agglomerated by the cohesion of molasses producing coalescence. The bonding forces necessary to obtain coalescence among agglomerates need to be significantly higher than the forces necessary for the primary particles' process of

nucleation [51]. In this case, the high viscosity of the molasses increases the bonding forces between the soil particles facilitating coalescence between soil particles.

Addition of molasses has an important effect on the failure mode of the soil. As the molasses content increases the failure mode becomes more ductile. The base-line soil sample (M0) had a brittle failure in which shear cracks fell along a plane to the heading of compression. On the other hand, the soil with the highest content of molasses (M12) showed a plastic failure with multiple fractures extending from top to bottom. Soil samples with the highest UCS (M2 and M8) had a brittle failure with longitudinal splitting. When comparing the failure planes of the unstabilized sample (M0) and the samples with the highest UCS, the change in inclination indirectly shows a cohesion and an angle of internal friction rise.
