Alkali activated soapstone waste : effects of co-binders and fibers on hardened-state properties
Rahim, Faraz (2019-07-30)
F. Rahim
30.07.2019
© 2019 Faraz Rahim. Tämä Kohde on tekijänoikeuden ja/tai lähioikeuksien suojaama. Voit käyttää Kohdetta käyttöösi sovellettavan tekijänoikeutta ja lähioikeuksia koskevan lainsäädännön sallimilla tavoilla. Muunlaista käyttöä varten tarvitset oikeudenhaltijoiden luvan.
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:oulu-201908022722
https://urn.fi/URN:NBN:fi:oulu-201908022722
Tiivistelmä
The metamorphic rock (soapstone) has been used since Stone age, even it plays a significant role in the economy of numerous countries. Currently, it is often used for architectural applications such as artefacts, cooking appliances, countertop and slab. Apart, it produces a massive amount of waste powder during the extraction phase and plant processing which is unavoidable. Resulting in a large amount of recyclable material landfilled or released to the environment annually that could be problematic in terms of environmental perspective.
To diminish its adverse impacts and ensure sustainability; it would be beneficial to thrive a new technique to recycle these industrial wastes in construction applications.
Based on previously published results; soapstone (Mg3Si4O10(OH)2) is poorly reactive in alkaline-activation owing to its chemical structure and a lack of amorphous components. As a result low mechanical properties which cannot be used for construction applications. Therefore, these types of materials necessitate co-binder, thermal curing at high temperature and high alkalinity to achieve high strength alkali-activated material.
Experimental and statistical investigates were conducted to observe the effects partially replacing of soapstone (talc) with co-binders (i.e., metakaolin, lime, stone wool, and silica fume), and fibers on the hardened-state properties. The variables used in the analyses were the concentration of virgin steel fibers or basalt fibers (dosages = 0.5% and 1%), the proportion of metakaolin, stone wool or silica fume used to replace soapstone (20 wt. %) and lime by 5 wt. %. The effects of employing fibers at two dosages with co-binders in 20 mix compositions were investigated. The designed mixtures were activated by using an alkali solution, which contains NaOH (10M) and sodium silicate (molar ratio of SiO2/Na2O = 2.5). The samples were treated by thermal curing at 60 °C for 24 hours, and placed under ambient conditions (24°C and 35% RH).
The findings showed that using co-binders and fibers were different behaviors on the hardened-state properties, however, the metakaolin reinforced mix composition with 0.5% basalt fibers improved compressive strength about 25 MPa after 28 days. This strength enables the use of the proposed binders for construction applications.
To diminish its adverse impacts and ensure sustainability; it would be beneficial to thrive a new technique to recycle these industrial wastes in construction applications.
Based on previously published results; soapstone (Mg3Si4O10(OH)2) is poorly reactive in alkaline-activation owing to its chemical structure and a lack of amorphous components. As a result low mechanical properties which cannot be used for construction applications. Therefore, these types of materials necessitate co-binder, thermal curing at high temperature and high alkalinity to achieve high strength alkali-activated material.
Experimental and statistical investigates were conducted to observe the effects partially replacing of soapstone (talc) with co-binders (i.e., metakaolin, lime, stone wool, and silica fume), and fibers on the hardened-state properties. The variables used in the analyses were the concentration of virgin steel fibers or basalt fibers (dosages = 0.5% and 1%), the proportion of metakaolin, stone wool or silica fume used to replace soapstone (20 wt. %) and lime by 5 wt. %. The effects of employing fibers at two dosages with co-binders in 20 mix compositions were investigated. The designed mixtures were activated by using an alkali solution, which contains NaOH (10M) and sodium silicate (molar ratio of SiO2/Na2O = 2.5). The samples were treated by thermal curing at 60 °C for 24 hours, and placed under ambient conditions (24°C and 35% RH).
The findings showed that using co-binders and fibers were different behaviors on the hardened-state properties, however, the metakaolin reinforced mix composition with 0.5% basalt fibers improved compressive strength about 25 MPa after 28 days. This strength enables the use of the proposed binders for construction applications.
Kokoelmat
- Avoin saatavuus [37798]