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Waste rock materials are becoming widely used in road pavement and building constructions in many countries. In this work, experimental laboratory tests were carried out on the waste rock produced from the extraction of the phosphate in the Kef-Essenoun mine, to study the performance of road pavement foundations built with these types of material. Two types of waste, namely phosphatic limestone (type 1) and limestone (type 2), were initially tested to determine the most suitable one to be used in pavement structures. The characterization tests showed that the presence of carbonate-fluorapatite and carbonatefluorapatite, and calcite, dolomite, and quartz are predominant in phosphatic limestone and limestone, respectively. The Los Angeles Abrasion (LA) and Micro-Deval (MD) values range from 59.9% to 90.4% and 42.05% to 86.31% for phosphatic limestone and from 43.64% to 95.88% and 38.25% to 75% for limestone. The CBR values of type 1 and type 2 waste were found to be 10.5% and 18.7% respectively. The results show that these materials, classified as B42ts and B42s respectively, could be used cautiously in capping layers and pavement backfilling materials. Furthermore, they must be treated with a hydraulic binder such as cement in order to improve their physical and mechanical properties. [ABSTRACT FROM AUTHOR]

Environmental problems on a global scale have become more prominent with the population growth. For the removal of organic contaminants, the solar energy and environmentally friendly photocatalysis are needed to substitute the fossil fuels. In this contribution, we report the synthesis, characterization and photocatalytic capability of CuAl2O4 nanoparticles. The spinel was elaborated by nitrate route and characterized physically and electrochemically for their correlations and application in photocatalysis through the degradation of Basic Red 46 (BR 46), a hazardous dye under visible illumination. The effects of several operational factors like the pH, catalyst dose and initial dye BR 46 concentration were optimized. The results revealed that the photocatalytic performance reached 93% at pH 10, 1 g/L of catalyst dose at a concentration of 10 mg/L of BR 46 within 120 min of irradiation. The quasi-total mineralization was confirmed by the total organic carbon (TOC) and dissolved organic carbon (DOC). Additionally, the prepared photocatalyst possesses a good cyclability with no significant change after five successive photocatalytic cycles. Furthermore, the radical scavenger tests revealed that the specie O2·− and the holes h+ have the significant effects on the removal of BR 46. Based on the latest results, a photocatalytic mechanism was proposed. [ABSTRACT FROM AUTHOR]