Influence of Wood-Based Biomass Ash Admixing on the Structural, Mechanical, Hygric, and Thermal Properties of Air Lime Mortars

Abstract

Mechanically-activated wood-based biomass ash (WBA) was studied as a potential active admixture for design of a novel lime-pozzolan-based mortar for renovation purposes. The replacement ratio of lime hydrate in a mortar mix composition was 5%, 10%, and 15% by mass. The water/binder ratio and the sand/binder ratio were kept constant for all examined mortar mixes. Both binder constituents were characterized by their powder density, specific density, BET (Brunauer–Emmett–Teller), and Blaine specific surfaces. Their chemical composition was measured by X-ray fluorescence analysis (XRF) and mineralogical analysis was performed using X-ray diffraction (XRD). Morphology of WBA was investigated by scanning electron microscopy (SEM) and element mapping was performed using an energy dispersive spectroscopy (EDS) analyzer. The pozzolanic activity of WBA was tested by the Chapelle test and assessment of the Portlandite content used simultaneous thermal analysis (STA). For the hardened mortar samples, a complete set of structural, mechanical, hygric, and thermal parameters was experimentally determined. The mortars with WBA admixing yielded similar or better functional properties than those obtained for traditional pure lime-based plaster, pointing to their presumed application as rendering and walling renovation mortars. As the Chapelle test, STA, and mechanical test proved high pozzolanity of WBA, it was classified as an alternative eco-efficient low-cost pozzolan for use in lime blend-based building materials. The savings in CO2 emissions and energy by the use of WBA as a partial lime hydrate substitute in mortar composition were also highly appreciated with respect to the sustainability of the construction industry.

Rheology, durability, and mechanical performance of sustainable self-compacting concrete with metakaolin and limestone filler

“…To confirm the pozzolanic activity of the metakaolin, it was measured following the French standard NF P18-513 [27]. The lower limit to be considered as pozzolanic is 650 mg of Ca(OH) 2 [28] and the results obtained with metakaolin used in this work provide a value of 946 mg of Ca(OH) 2 ; hence, metakaolin is considered to be a pozzolanic material. Finally, fine (FA) and coarse (CA) crushed aggregates (limestone) were used, with nominal size of 0-4 and 6-12 mm.…”

Mortars with Crushed Lava Granulate for Repair of Damp Historical Buildings

“…On this account, there is a need to develop new mortars for plastering, rendering, and masonry purposes that will be compatible with materials originally inbuilt and for their properties to comply with present technical and functional standards. Due to several severe problems associated with the use of PC-based mortars in repair works [27,28,29,30,31], they are no longer applicable for rendering and plastering of historically valuable buildings and cultural heritage monuments. As PC has some inadequate properties and is incompatible with many traditional materials inbuilt in historical buildings [32,33,34,35], air lime, natural hydraulic lime, lime-pozzolan, and PC-lime-based mortars represent alternatives to PC mortars which are too rigid, low water vapor permeable, and susceptible to frost damage.…”

Sustainable Hybrid Lime Mortars for Historic Building Conservation: Incorporating Wood Biomass Ash as a Low-Carbon Secondary Binder

“…In contrast, research on employing WBA as a pozzolanic and/or hydraulic component in the formulation of hydraulic lime, which is the focus of this research, is still limited. Previous studies have focused almost exclusively on the influence of WBA addition on the properties of air-lime mortars [28][29][30][31][32], while only a few papers in the literature place WBA within the framework of a hydraulic lime framework [33][34][35][36]. As hydraulic lime is a favorable material for use in buildings subjected to considerable atmospheric action [37,38], its value must be highlighted when used in historic buildings, instead of air-lime, which is often considered the material most like the materials originally used.…”