Unstable swelling behaviour of alkali silica gels: Fid-Bau Portal

Unstable swelling behaviour of alkali silica gels

Struble, Leslie / Diamond, Sidney

AbstractSome members of a suite of alkali silica gels tested for free swell and for swell under constant applied load showed unexpected behavior, which we attribute to structural rearrangements within the affected gels. Access to water while these particular gels were loaded resulted in increased swelling compared to the unloaded replicates tested for free swell. In some instances this enhanced swelling under load was terminated by a sudden liquification of the gel. Finally, a single gel tested after aging four months had lost all its ability to swell or to generate swell pressure. Some implications of these observed instabilities on the possible behavior of gel in concrete affected by alkali silica reaction are discussed.

ResumenAnumiţi membri ale unor categorii de geluri alcaline de silica, studiate pentru dilataţie liberǎ si pentru extindere sub presiune constantǎ au arǎtat o manifestatié neastepta $$ ̀$ a, care noi o attibuim pe seama rearanjamentelor structurale din gelurile afectate - Apa fiind disponibilā concomitent cu aplicarea presiunii, a rezultat in mǎrirea dilatǎrii, decit in lipsa presiunii. In anumite cazuri aceastǎ expansiune a gelurilor sub presiune, s-a terminat printr-o lichiefiere abruptǎ a gelului. In încheire, un gel studiat dupā patru luni de îmbātrînire şi-a pierdut toatá abilitatea sǎ se dilate s-au sā producā presiune de dilatatie. Anumite implicaţii ale acestor instabiliţāti, la o posibilà comportare a gelului in concret afectatà de reacţia dintre silalcalii sînt tratate.