Optimisation of hydraulic lime mortars incorporating an oil-refinery catalyst by-product for sustainable building rehabilitation

Journal Article (2026)
Author(s)

Carla Costa (Universidade de Lisboa)

Sandra Nunes (TU Delft - Civil Engineering & Geosciences)

Research Group
Concrete Structures
DOI related publication
https://doi.org/10.1016/j.dibe.2026.100860 Final published version
More Info
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Publication Year
2026
Language
English
Research Group
Concrete Structures
Journal title
Developments in the Built Environment
Volume number
25
Article number
100860
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15
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Abstract

This investigation employs a Central Composite Design-based Design of Experiments (DoE) methodology to develop hydraulic lime mortars incorporating equilibrium catalyst (ECat), a by-product generated at the fluid catalytic cracking unit in oil refineries. The derived mathematical models describe the quantitative effects of key mixing variables, specifically ECat content, water-to-binder ratio and water repellent dosage, as well as their cross-interactions, on mortar properties, namely workability, compressive strength, ultrasound propagation velocity and dynamic modulus of elasticity. Numerical optimisation techniques enabled the identification of optimal lime mortar compositions that maximise eco-efficiency while ensuring compliance with both regulatory and technological requirements for diverse masonry applications, including the rehabilitation of ancient buildings. Results confirm the by-product upcyclability of ECat, with feasible incorporation levels up to 56.6 % by mass, yielding mortars with significant potential for reducing the environmental impact of the built environment while advancing the circular economy and fostering technological innovation in the construction sector.