Moroccan clays for potential use as aluminosilicate precursors for geopolymer synthesis

Abstract

Three Moroccan clays, denoted A1, A3 and A5, were sampled from the Fez region with the aim of potential use as aluminosilicate precursors for geopolymer synthesis. Each clay was subjected to calcination at 700 °C and analyzed using DTA/TG, grain size distribution measurements, XRD, and FTIR spectroscopy before and after heat treatment. The results showed that the three clays contain kaolinite in different proportions in addition to some associated minerals, such as quartz, hematite, calcite and dolomite. Heat treatment successfully activated the clay by the amorphization of kaolinite, which is essential for geopolymerization. Some other changes were observed in the associated minerals, especially carbonates, which partially or totally decomposed depending on the clay, while other minerals remained intact. The SBET and NBO values are in accordance with the degree of polymerization, and the obtention of consolidated materials is possible by alkali activation of the calcined clays.

Review of Recent Developments Regarding the Durability Performance of Eco-Friendly Geopolymer Concrete

“…Both FA and GGBS undergo suitable treatment processes before being utilized as geopolymer materials in construction projects [47]. In addition, other waste materials were used to produce GPC, such as rice husk ash [63], waste glass [64], palm oil fuel ash [65], ceramic waste [66], bagasse ash [39], illitic clay [67], Moroccan clays [68], clay minerals [69], and smectite clay [70], silica fume [65], waste clay brick [71], waste bricks powder [72], sewage sludge ash [73], and basalt powder [74]. Alkali-activated materials can generally be divided into two groups: (a) the high calcium system, where GGBS is a representative precursor and results in the formation of a C-A-S-H type gel as the main reaction product; and (b) the low calcium system, where class F FA and metakaolin are representative raw materials and produce N-A-S-H type gels within a three-dimensional network as the main reaction product [75].…”

Alkali Activation of Clay and Water Potabilization Sludge Binary Blends: Influence of Composition and Curing Conditions

“…In particular, the type of precursor strongly influences the properties and the possible applications of AAMs. Among the natural resources, clays are well-known precursors to, especially, kaolinitic clays [11,12], although the use of non-kaolinitic clays has been rapidly growing in recent years [13][14][15][16][17][18]. Different authors have proposed the valorisation of local resources as a strategy for the transition towards a sustainable raw materials supply chain [19].…”