| Title |
Lightweight, heat-insulating, alkali-activated slag composites with carbon-based biochar additive and filler |
| Authors |
Tamošaitis, Gintautas ; Vaičiukynienė, Danutė ; Kantautas, Aras ; Villalón Fornés, Ignacio ; Borg, Ruben Paul ; Vitola, Laura |
| DOI |
10.3390/ma19020277 |
| Full Text |
|
| Is Part of |
Materials.. Basel : MDPI. 2026, vol. 19, iss. 2, art. no. 277, p. 1-18.. ISSN 1996-1944 |
| Keywords [eng] |
acoustic insulation ; alkali-activated materials ; biochar waste ; metallurgical slag ; thermal conductivity |
| Abstract [eng] |
An alkali-activated slag binder based on biochar was developed in this research. The biochar was produced from waste wood and is referred to as biochar waste (BW). In the alkali-activated slag system, a small amount of biochar (up to 0.5%) was used as an additive, and a larger amount (from 1% to 25%) was used as a filler. The influence of the biochar powder on compressive strength was determined. The hydrated samples were investigated using X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM), and the thermal, acoustical properties, and hydration temperature were also determined. The compressive strength of the alkali-activated slag composite, especially after 7 days, was found to increase slightly due to the introduction of a small amount (0.05-0.5%) of BW powder. The powder in the alkali-activated slag matrix was distributed homogenously, resulting in a reduction in the crack propagation. A larger amount of BW led to a non-homogeneous distribution, and this resulted in a gradual reduction in compressive strength with increasing BW. The highest values of compressive strength at 28 days of hydration (44.4 MPa) were recorded for samples with 0.25% of BW. According to mathematical analysis methods, the compressive strength is mainly influenced by the specific surface area of the initial mix ingredients and the amount of BW additive. In the alkali-activated slag matrix, BW acted as an inert micro-filler, with the dilution effect possibly being the reason for the decrease in the hydration temperature. SEM analysis demonstrated that the BW had a good adhesion with the alkali-activated slag matrix. The thermal and acoustic insulation performance of samples with BW improved. These investigations suggest that BW can be successfully incorporated in alkali-activated material, resulting in low thermal conductivity and adequate acoustic insulation performance. |
| Published |
Basel : MDPI |
| Type |
Journal article |
| Language |
English |
| Publication date |
2026 |
| CC license |
|
