LIFETIME RESEARCH OF RAPID-HARDENING FOAMS

Abstract

The results of the study of the time of existence of fast curing pins obtained on the basis of six gelforming systems are presented. The time of destruction of fast curing pins was experimentally determined. It was found that the foam obtained on the basis of Na2O·nSiO2 + NH4Cl system, which in the previous studies showed the best results in economic parameters, has the worst indicators of life time among the studied foams. The foam obtained on the basis of the Na2O·nSiO2 (9 %) + NaHCO3 (9 %) system was found to provide the greatest lifetime. It was established that the lifetime of the foam obtained on the basis of Na2O·nSiO2 (9 %) + NaHCO3 (9 %), at the height of the initial foam layer hst = 5 cm, is 24 ± 2 h, and at hst = 10 cm or hst = 15 cm foam life is 48 ± 2 h. This figure is much higher than the lifetime of a similar layer of air-mechanical foam. The effect of the addition of foaming agent on the gel formation time is investigated. It was found that adding 2-6% foaming agent to the gel-forming systems does not change the gel-forming time for each of them. The effect of different types of foaming agents on the existence of fast curing foams has been investigated. It has been experimentally found that a 6 % «Morskoy» foaming agent provides the highest stability of fast curing foam over time. The foam obtained with the addition of "SOFIR AFFF 6%" (fluoro-synthetic film-forming) foam has the worst performance. All other foaming agents gave a positive result close to that of the «Morskoy» foaming agent. It is proposed to increase the time of loss of fluidity for the investigated gel-forming systems to 150 s. It was found that with increasing initial thickness of the fast curing foam layer, its lifetime increases.