Selection of lime-based repair mortars for heritage structures using MCDM techniques: a comprehensive study

The study examined use of lime-based mortars for repair of heritage structures. The twelve criteria considered for the study were compressive strength, transverse strength, salt crystallisation resistance cycles, shrinkage, alkali resistance, water absorption, porosity, capillary absorption, energy consumption, total emission, environmental load, and bulk density. Two types of hydrated limes (Lime-I and Lime-II) with replacements of ground granulated blast furnace slag (GGBS) or fly ash from 0 to 75% were used for the preparation of lime-based mortars with binder to aggregate weight proportions of 1 : 3 and 1 : 1. Experimental data was collected based on the criteria and the analytical hierarchy process (AHP) was used to establish their weightages. Multi-criteria decision making (MCDM) analysis was performed using technique for order performance by similarity to ideal solution (TOPSIS), PROMETHEE-II, VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR), and elimination and choice expressing reality (ELECTRE) methods. The results of the analysis showed that Lime-II based 1 : 1 mortar with 66% replacement of lime with GGBS was the most promising lime-based mortar for repair of heritage structures.