Mechanical, microstructural and mineralogical evaluation of alkali-activated waste glass and stone wool

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

“…It follows that also the dissolution of the SW is only partial. However, waste SW alone could be alkali-activated as confirmed in our previous study, 10 but it takes one week to be able to demould and measure bending and compressive strengths and therefore co-binders such as M, slag, and L were added. In order to see the differences in dissolution and formation of the matrix, we performed SEM-EDS point analyses and calculated the average Si/Al, Si/Na, Ca/Al, and Na/Al ratios.…”

“…Therefore, a higher temperature (e.g., 40 • C for three days) is recommended to accelerate early strength. 10 However, the study of Yliniemi et al shows that one day at 40 • C is enough for SW and GW when using sodium silicate as an alkali activator, but compressive strength < 3 MPa was measured when GW was alkali-activated by NaOH. 3 To apply a less energyintensive process in the foreseen pilot production of façade panels, instead of increasing the temperature of curing, the addition of co-binders was preferred.…”

“…In the previous study, alkali‐activated samples using waste SW and a combination of sodium silicate/NaOH as alkali activators show compressive strengths below 10 MPa after 7 days of curing at the room temperature and below 5 MPa when using GW as a precursor. Therefore, a higher temperature (e.g., 40°C for three days) is recommended to accelerate early strength 10 . However, the study of Yliniemi et al.…”

Environmental and Biological Impact of Fly Ash and Metakaolin-Based Alkali-Activated Foams Obtained at 70°C and Fired at 1,000°C

“…In the most general description, AAMs are inorganic systems consisting of two main components: a reactive solid component mainly composed of amorphous aluminosilicate, also called precursor, and an alkaline activator solution, the activator, where different alkali hydroxides and silicates, as well as carbonates and sulfates, come into consideration ( Provis and van Deventer, 2013 ). There are many kinds of aluminosilicate source suitable to be used such as metakaolin (also the most studied one) ( Clausi et al, 2016 ), kaolin ( Balczar et al, 2016 ; Esaifan et al, 2015 ; Sgarlata et al, 2021 ), calcinated clays ( Provis, 2018b ), fly ashes ( Rakngan et al, 2018 ), various slags ( Adesanya et al, 2017 ; Češnovar et al, 2019 ), different types of mineral wool ( Pavlin et al, 2021 ), volcanic ash ( Djobo et al, 2016 ), and red muds ( Badanoiu et al, 2015 ). The microstructure and therefore the overall performance (mechanical properties, the durability of the material) of the alkali-activated binder is strongly dependent on various factors such as type and amount of precursor, particle size distribution, presence of amorphous phase, Na(K)/Si/Al ratio, type and concentration of the activator, the curing regime, etc.…”

Studying the Effect of High Temperature on the Content of Glass and Brick Waste Binders after Alkaline Activation

“…The idea of searching for minerals waste capable of withstanding the highest temperatures, after undergoing the alkaline activation process is considered an achievement, especially those that lack the pozzolanic effect and are classified under inert wastes, On the other hand, inert wastes can be transformed into effective once they are crushed with a high fineness that competes with cement or more, as a preliminary phase before stating the chemical activation process, This is called mechanical activation, which allows the appearance of the pozzolanic effect, All this in order to manufacture a material, which works on the construction of buildings and structures on a large scale, that is durable enough, and must be able to absorb energy and resist high temperatures, such as nuclear power stations, radioactive waste storage facilities and others [1], in addition to preserve and protect the environment from pollution, in order to reduce global warming, by reducing the proportion of Portland cement production, which allowed the field of scientific research to find alternative binders to cement based on waste materials, including alkaline activated materials (AAM) [2]. Among the industrial waste that has become used as a primary and basic material in the alkaline activation process, it was found that glass of all kinds, as well as red bricks, are classified into the list of alternative materials for cement materials, which can reduce energy consumption during manufacturing, thus, it allows giving materials called geopolymers, the success of geopolymers was based on the introduction of multiple industrial solid wastes during its manufacture [3].…”