Ternary Blended Binder for Production of a Novel Type of Lightweight Repair Mortar

Abstract

The goal of the paper was development and testing of a novel type of ternary blended binder based on lime hydrate, metakaolin, and biomass ash that was studied as a binding material for production of lightweight mortar for renovation purposes. The biomass ash used as one of binder components was coming from wood chips ash combustion in a biomass heating plant. The raw ash was mechanically activated by grinding. In mortar composition, wood chips ash and metakaolin were used as partial substitutes of lime hydrate. Silica sand of particle size fraction 0–2 mm was mixed from three normalized sand fractions. For the evaluation of the effect of biomass ash and metakaolin incorporation in mortar mix on material properties, reference lime mortar was tested as well. Among the basic physical characterization of biomass ash, metakaolin and lime hydrate, specific density, specific surface, and particle size distribution were assessed. Their chemical composition was measured by X-Ray fluorescence analysis (XRF), morphology was examined using scanning electron microscopy (SEM), elements mapping was performed using energy dispersive spectroscopy (EDS) analyser, and mineralogical composition was tested using X-Ray diffraction (XRD). For the developed mortars, set of structural, mechanical, hygric, and thermal properties was assessed. The mortars with ternary blended binder exhibited improved mechanical resistance, lower thermal conductivity, and increased water vapor permeability compared to the reference lime mortar. Based on good functional performance of the produced mortar, the tested biomass ash could potentially represent a novel sustainable alternative to other pozzolans commonly used in construction industry. Moreover, reuse of biomass ash in production of building materials is highly beneficial both from the environmental and economic reasons especially taking into account circular economy principles. The ternary blended binder examined in this paper can find use in both rendering and walling repair mortars meeting the requirements of culture heritage authorities and technical standards.

Mortars with Crushed Lava Granulate for Repair of Damp Historical Buildings

“…Quantitatively similar moisture absorption observed, e.g., Pavlíková et al 2019 [87] who obtained lime-based repair mortar A w = 0.32 kg/(m 2 ∙s1 /2 ) [84]. Also, Fusade et al [88] obtained NHL mortars water absorption coefficient in the range 0.30–0.379 kg/(m 2 ∙s1 /2 ).…”

“…The lower porosity of cement-lime mortar and the structure of PC hydrates were the cause of low water absorption. Therefore, PCHL-R and PCHL-LA mortars were found to be not suitable materials for repair of damp masonry, where high water absorption in time is the positive effect, as it would enable the mortar to better absorb moisture from the surrounding masonry and help it dry out as stated by Fucade et al [88].…”

Lightweight Vapor-Permeable Plasters for Building Repair Detailed Experimental Analysis of the Functional Properties

“…The water vapor permeability was higher for wet cup arrangement of the test than that of assessed in the dry cup analysis. Similar material performance in the different conditions of the cup experiment was observed, e.g., in [ 46 , 47 , 48 ]. The acceleration of water vapor transmission in the wet cup test can be attributed to the reduced surface binding forces between water vapor molecules and pores due to the filling by water molecules within samples conditioning for the test [ 49 ].…”

Zeolite Lightweight Repair Renders: Effect of Binder Type on Properties and Salt Crystallization Resistance

“…The reduced surface bonding of water vapor molecules in the wet-cup experiment resulted in the acceleration of water vapor transmission, and thus lower water vapor resistance factor in comparison with the results of the dry-cup test. Such performance of porous building materials has been documented, e.g., in [70][71][72].…”