Production of lightweight aerated alkali-activated slag pastes using hydrogen peroxide

Production of Lightweight Alkali Activated Mortars Using Mineral Wools

“…Water absorption and permeable porosity were increased significantly with decreasing density (or increasing the foam content). Similar findings were found in [55,67]. Since the results conflict with Nambiar et al [68], who observed a reduction in water absorption with a decreased density of OPC/FA-based foam concrete.…”

“…Moreover, it was noticed that the reductions in the flexural strength due to the reduction in density had a lower rate than the measured reductions in the compressive strength. Similar findings were found in [52,55,61]. However, Abdollahnejad et al [15] indicated that no correlation between compressive strength and density in lightweight FA-based AAM could be established.…”

“…Compared to the findings in [50], where the specimens with a density of 750 kg/m 3 for the lightweight slag-based AAM achieved a normalized strength (average strength/average density) of about 0.6 kN·m/kg, a higher normalized strength of around 1.6 kN·m/kg was detected in SW50/GW10-2% Fiber-35% Foam (≈775 kg/m 3 ). Moreover, it was stated in [15,55,56] that the flexural strength-to-compressive strength ratio of the lightweight cementitious compositions is in the range of 0.1–0.58, while in this study a ratio of (0.8–2.2) was recorded, which can be attributed to the inclusion of the PP fiber. Zollo et al [57,58] demonstrated the significant improvement of the mechanical properties of the lightweight OPC-based concrete reinforced with the PP fiber.…”

“…This phenomenon is due to the higher porosity in the specimens with higher foam content, which led to higher water penetration and release of alkali cations [1,18]. However, the efflorescence observations of this study conflict with Zhang et al [66] and Şahin et al [55]. In [66], fly ash-based foamed AAM was monitored to investigate the effects of the pore structure on the efflorescence.…”

“…Nevertheless, in the same study, the efflorescence products were detected by optical microscopy, and it was observed that the efflorescence products were accumulated and trapped inside the macro-pores. Similarly, Şahin et al [55] explained the lower efflorescence of lightweight AAM by its lower solid content, which resulted in a reduction of leachable alkali solution. Furthermore, they stated that the higher porosity and pore size would limit the leaching of the alkali solution.…”