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This paper deals with building envelope thermal performance through a comparative study of the use of two types of construction materials, such as CEB and cement blocks, in order to introduce the use of double walls in sustainable buildings' construction. The building envelope participates in providing thermal comfort to users and in the optimal management of building energy consumption. This study begins with a survey of public preferences for building materials used in Burkina Faso. The results indicate that 76% of the people surveyed opt for cement blocks over local materials.  Concerning the thermal and specific energy performance, three variants of building envelope were studied: CEB walls, cement blocks and the double-wall (CEB + Cement blocks). It appears that the CEB walls are more efficient than the cement block walls. The introduction of double envelopes leads to the thermal resistance of 357.37m².K/W and reduces the heat flow from 85.32% to 90.24% compared to the wall made with CEB and cement blocks. This approach, which consists in mixing construction materials for good thermal insulation, allows improving the envelope thermal performance and the overall building energy performance.

This paper presents a prediction of thermal behavior of bioclimatic building by the mean of time lag. Firstly, we provided locally made materials with commonly known thermal properties. Afterwards, we conducted a simulation of a building free of internal charges on the TRNSYS 16 (Transient system simulation) platform. This simulation has focused on the collection of thermograms concerning the inside and outside surfaces (exposed to solar radiation) temperatures of walls oriented South, East, North and West on the basis of a weather file called Meteonorm. An analysis of the results was conducted which leaded to the conclusion that time lags of East oriented walls is greater than that of the other walls. Furthermore, the simulation confirms that the lower the value of thermal diffusivity is, the greater the corresponding time lag is. Finally, the results of the investigations revealed that the locally designed materials have greater time lag than that of commonly use materials, like concrete. Therefore, they consume less energy as construction materials.

The method used to evaluate the quality of concrete in structures includes, among other things, compressive strength testing of specimens cast on site. This method has shortcomings due to the non-uniformity in their formulation processes of the concrete studied in laboratories and that of the structure on site and the tardiness in obtaining test results. This is why the development of reliable methods of non-destructive assessment of the compressive strength of concrete in situ is essential for a better performance assessment of structures.There are a multitude of non-destructive methods, but in this article, the ultrasonic pulse velocity (UPV) and the rebound hammer (RH) are the methods used as they are easy to get manipulate, accessible and permit fast access to results. Analyses using single and multiple linear regression methods have been carried out with the results from compression tests and measurements of pulse velocity and rebound indices carried out between February and April 2018 on over 90 specimen samples in total. This resulted in correlation equations for the in-situ estimation of the compressive strength of the concrete studied.

This study permitted to evaluate the adequacy of an existing Nubian vaulted building with the "bioclimatic" concept including the performance of its envelope. In that purpose, we needed to analyze its architectural concept and to measure parameters such as the temperature of the internal and external surfaces of all the façades (walls, roof and floor) of the study building. The measurement campaign took place over three (03) days in the month of January 2018 with a one-hour step for temperatures. Out of eleven (11) bioclimatic principles identified, six (06) were respected in the design of the building. In addition, we obtained thermal amplitudes of the interior surfaces lower than 1.5°C for the walls and 5°C for the roof, a decrement factor lower than 12% for the walls and 17% for the roof and a thermal time lag of 6 to 8 hours on in average for the walls and 4 to 6 hours in average for the roof. Finally, after evaluation of the thermal loads, with the Nubian vault building a reduction of a bit more than one third (1/3) of the thermal loads is achieved comparatively to a building of the same size made of cinder blocks for the walls and aluminum roofing sheet. However, this comfort offered by the Nubian vault can be improved with more bioclimatic provisions which we have recommended.