Self-compacting geopolymer concretes: Effects of addition of aluminosilicate-rich fines

Influence of fine aggregates on the microstructure, porosity and chemico-mechanical stability of inorganic polymer concretes

“…Hence, the increase of the recycled glass content will increase the moisture content which is detrimental for the chemical stability and durability of the matrices. Even though the presence of fines automatically increased the strength and reduced the pore threshold, it appeared that amorphous cementitious materials generate high moisture content detrimental for the durability of the matrices [19]. These observations agree with the results found by van Deventer et al [26] for geopolymers obtained with slag and fly ash.…”

“…The dissolved fraction obtained after treatment of the three fines (1 g) in a concentrated sodium hydroxide (8 M, 100 ml) solution for 24 h at 80°C using a sample holder in Teflon Ò [for more details see Ref. [19]] showed more aluminum and silicon from pumice, whereas the recycled glass showed a quantity of silicon in the same order as pumice but with aluminum six time lower. The released fraction of silicon in feldspar sludge was the 1/10 of that of pumice and the aluminum was almost the half (Table 1).…”

“…The primary action of fines into metakaolin based inorganic polymer cements and concretes is to stabilize the matrix: (i) chemical stability with elimination of residual alkali cations and Aloligomers with formation of new H-N-A-S gels; (ii) physicomechanical stabilization with the increase in density and strength [19]. As evidenced by Hajimohammadi et al [25], the rate of alumina released from different precursors is a critical controlling factor in the formation of mechanically strong and durable geopolymer phases.…”

“…When the amorphous fines is composed of alumina and silica, it will easily form additional geopolymer gels into the pore solution. This phenomenon will lead to pore refinement and to chemico-mechanical stability presenting a decrease in the moisture content with the extension of curing time [19]. Considering the semicrystalline fines, the quick and effective reactivity in a short period of time reduces the moisture content as soon as possible.…”

“…The pore threshold, the volume of permeable voids, the strength [19], the moisture control capacity as well as the phases evolution are used for the prediction of the stability and durability of the IPC concretes. The prediction take into account the durability indices established by Baroghel-Bouny et al [20][21][22] and Bernal and Provis [13].…”