scholarly journals Preparation of façade panels based on alkali‐activated waste mineral wool, their characterization and durability aspects

2022 ◽  
Author(s):  
M. Pavlin ◽  
B. Horvat ◽  
V. Ducman
Keyword(s):  
Mineral Wool ◽  
Alkali Activated

scholarly journals Deformation of Alkali-Activated Materials at an Early Age Under Different Curing Conditions

2021 ◽  
Vol 9 ◽  
Author(s):  
Mark Češnovar ◽  
Katja Traven ◽  
Vilma Ducman
Keyword(s):  
Relative Humidity ◽  
Room Temperature ◽  
Standard Procedure ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Mineral Wool ◽  
Cement Pastes ◽  
Curing Conditions ◽  
Material Sources ◽  
Alkali Activated

The production of alkali-activated materials (AAMs) is known for its environmentally friendly processing method, where several amorphous-rich aluminosilicate material sources combine with an alkali media solution to form solid, ceramic-like materials. In terms of the Si:Al, Na(K):Al, and Na(K):H2O ratios, the theory of AAM formation is quite well developed, but some open questions in the technology process remain, especially with regards to the means of curing, where the generation of defects can be persistent. Knowing that deformation is extremely high in the early ages, this study investigates the effects of temperature and moisture on shrinkage behavior within the first 72 h of AA pastes made from ladle (LS) and electric arc furnace (EAF) slag and activated by sodium silicate (Na2SiO3). The method to determine the deformation of alkali-activated slag-based materials, in terms of both autogenous and drying shrinkage, was based on the modified ASTM C1698-19 standard for the measurement of autogenous shrinkage in cement pastes. Autogenous deformation and strain were measured in four samples, using the standard procedure at room temperature, 40 and 60°C. Furthermore, using an adjusted method, nine samples were characterized for strain and partial surface pressure, while drying at room temperature, 40, or 60°C at a relative humidity of 30 or 90%. The results show that the highest rate of autogenous shrinkage occurred at a temperature of 60°C, followed by drying shrinkage at 60°C and 30% relative humidity, owing to the fact that the rate of evaporation was highest at this moisture content. The study aimed to provide guidance regarding selection of the optimal curing set in order to minimize deformations in slag-based alkali-activated materials. In the present case, curing at a temperature of around 40°C under lower moisture conditions for the first 24 h provided optimal mechanical properties for the slags investigated. The methodology might also be of use for other aluminosilicate sources such as metakaolin, fly ash, and mineral wool–based alkali-activated materials.

scholarly journals Production of Lightweight Alkali Activated Mortars Using Mineral Wools

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1695 ◽  
Author(s):  
Ahmad Alzaza ◽  
Mohammad Mastali ◽  
Paivo Kinnunen ◽  
Lidija Korat ◽  
Zahra Abdollahnejad ◽  
...  
Keyword(s):  
Drying Shrinkage ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Mineral Wool ◽  
Dry Density ◽  
Micro Computed Tomography ◽  
Hardened State ◽  
Compressive And Flexural Strengths ◽  
Alkali Activated

This experimental study aimed to develop a fiber-reinforced lightweight mineral wool-based alkali activated mortar. The lightweight mineral wool-based alkali activated mortars were produced using premade foam and reinforced by polypropylene (PP) fibers. They were assessed in terms of fresh and hardened-state properties. Fresh-state properties were investigated by mini-slump tests. Hardened-state characteristics were assessed by ultrasonic pulse velocity, dry density, compressive and flexural strengths, drying shrinkage, efflorescence, water absorption, and permeable porosity. For the first time, the resistance of the synthesized lightweight mineral wool-based alkali activated mortars against harsh conditions (carbonation, freeze and thaw, and high temperature) were evaluated. The porous structures of the developed lightweight alkali activated mortars were also analyzed using an X-ray micro-computed tomography (CT) technique. Lightweight mix compositions with densities in a range of 770–1510 kg/m3, compressive strengths of 1–9 MPa, and flexural strengths of 2.6–8 MPa were developed. Increases in both density and strength after carbonation were also recorded, while a decrease of strength was noticed after exposure to freeze/thaw and high temperatures of up to 500 °C.

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