🗏 : 316-323
The article evaluates the influence of various plasticizing and structure-forming additives on the hydration process of non-autoclaved aerated concrete (NAC). The authors have developed a method for the NAC formation with the introduction of the following modifiers: lignosulfonate (LS), graphene oxide (GO) (1 % aqueous suspension) and a complex additive – GO/LS. The formation of the structure and the study of new mineral formations in cement stone as a result of hydration were carried out by X-ray diffraction and differential thermal analysis. According to XRD-analysis, gas blocks of all compositions contain quartz, tobermorite, calcium hydrogarnets, xonotlite, C–S–H(I), and calcite. The diffraction pattern of the sample with the addition of GO/LS shows that NAC contains, first of all, high-intensity reflections of tobermorite, xonotlite, as well as C–S–H and calcite. All other NAC samples are characterized by a lower intensity of reflections of the indicated calcium hydrosilicates. TG- and DSC-curves for all studied gas blocks have a similar character – 3 stages of weight loss, except for the control sample. Aerated concrete without additives at temperatures up to 100 °С loses 0.96 % of its weight, with the addition of LS – 1.20 %, GO – 1.35 %, and complex additive – 1.72 %. In the temperature range of 400–500 °С, an endothermic effect appears, which indicates the dehydration of weakly crystallized gel-like hydrosilicates and calcium hydrogarnets. It is this peak that is absent in the control sample. Thus, based on the diagnostic results, it was established that the complex modifying additive allow to increase of the hydration product crystallinity of the hardened NAC. The results suggest that the modified NAC containing a complex additive is more stable and functional during operation than comparative samples of concrete of a traditional composition without this additive.