Mineralogical, physico-chemical and technological characterization of clay from Bensmim (Morocco): Suitability for building application

•The unexploited clays from Bensmim were evaluated for their use in clay brick production.•The effect of the properties of raw materials, and firing temperature on the properties of the fired bricks was studied.•Bensmim bricks show good thermal conductivity and low linear shrinkage.•The low plasticity in Bensmim clays limits their use in construction material field.•Compressive strength of Bensmim clay can be improved by the addition of plastic clays. This study aims at the valorization of unexploited clay from a rural village called Bensmim by investigating its potential suitability as a construction material. Two clays samples (Babmansour and Extrabrick) used in the clay brick manufacturing were also considered as a reference. The followed methodology consists of identifying the physicochemical properties of the raw materials and examining its influence on the final products properties (linear shrinkage, thermal conductivity, and compressive strength). The firing characteristics of the samples under study at different temperatures (650 °C, 850 °C, and 950 °C) were determined by linear shrinkage, compressive strength, and thermal conductivity. The results show that the clayey fraction of Bensmim consists mainly of illite and kaolinite. However, Extrabrick and Babmansour contain kaolinite with moderate amounts of smectite. The major oxides presented in all clays samples are SiO2 (57–59.6 wt%), Al2O3 (10.38–23.29 wt%), and Fe2O3 (3.78–6.58 wt%). The amount of CaO in Extrabrick clay is about of 10.61% and 11.14% for Babmansour, whereas it is almost absent in Bensmim clay. Extrabrick and Babmansour clays samples are considered as calcareous clay (CaO > 10%) characterized by a moderate specific surface and high plasticity due to their high clay fraction and moderate smectite content. While Bensmim has a weak specific surface and low plasticity due to the absence of swelling phase in its clay fraction and the excessive amount of sand. The performed tests attest high thermal properties of Bensmim clay, with good linear shrinkage. Unfortunately, under 950 °C, Bensmim clay presents low compressive strength. However, this can be adjusted by a small addition of the plastic clays.