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.

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Cost overruns are frequent in the construction industry. They become greater the more the construction project is delayed. In developing countries, this situation is recurring and constitutes a significant financial problem. In a time-overrun context, our objective is to find a method that can enable us to reduce the delay while minimizing the subsequent cost overruns. We thus developed a mathematical model named CCOMTOC (construction cost optimisation model in time-overrun context). The model was tested and results reveal that the reduction of cost overruns is effective. We showed that in a time-overrun context, according to the importance of delay penalties, we obtain two distinct situations. On the basis of the reference cost calculated for a maximum compression of tasks within the normal duration, we note that, for low delay penalties, the total cost after further delays to the estimated completion time decreases as we deviate from the initial completion time. On the other hand, for relatively high delay penalties, the cost first passes by a minimum before increasing regularly during the further delays to the estimated completion time.Key words: time overrun, optimization, linear programming, time skid, delay make-up, cost overrun.

Abstract:The critical housing shortage in cities of the developing countries like Cameroon generates an ever-growing desire to increase housing supply. The main group of actors in this domain are by and large the formal sector, while the informal sector is still inactive. Because of the legalities and costs associated with the formalities surrounding the provision of formal housing, the majority of urban residents are bypassed by the formal housing policies. The only alternative for them is thus self-construction. This mode of housing provision, although difficult, has become a dominant mode of providing housing within the construction sector of the developing countries. Consequently, this mode of housing provision now features in mainstream specialised literature, with an aim to promote the sector. Furthermore, several techniques of mastering self construction costs have been elaborated. However, given the complexity of abundant (albeit unqualified) labour, there is still a case for further research in the self-construction forms of housing, especially in terms of their adaptability. The sector is criticised for being characterised by unclear cost accounting methods, as well as the ubiquitous below-par management techniques which themselves lead to delays in the completion of such housing projects. In light of the foregoing exposition, the article presents a method of estimating labour costs based on a developed matrix model. Through the introduction of the finite dimensional vector space made up of the standard tasks, the model draws up a direct relationship between the quantity of work and the labour cost. The illustration of this new approach, through a case study shows that it is possible to reduce the labour cost of up to 37%, compared to the simple matrix method as examined by other researchers. The Developed Matrix Approach (MASTA) based on standard tasks thus constitute a decision-making tool that is not only for optimisation of productivity but also a symbol of good management