Simplified EcoAudit tool mirrors full life cycle assessment of cement tiles

Cement tiles have been marketed for decades as a greener alternative to fired ceramic coatings, but a new study suggests that judging their environmental credentials depends heavily on how you measure them.

The study, published in Discover Civil Engineering, was carried out by Raphaela Ristow, Enrico Fava, Agenor De Noni Jr. and Dachamir Hotza. It revisited the environmental performance of cement tiles, a traditional flooring and wall material popular in Brazil, England and Mediterranean countries. The tiles date back to the nineteenth century and are prized for their artisanal manufacture and exceptional durability, often exceeding a century of service life even in high-traffic buildings such as churches and public structures. Because they are produced without firing, they are frequently promoted as a sustainable choice, yet they rely heavily on Portland cement, one of the most carbon-intensive materials in the world.

The researchers used a functional unit of one square metre of cement tiles, equivalent to 25 tiles, drawn from three different factories. The reference data came from a previously published cradle-to-gate LCA by Assumpção de Castro and colleagues, which tracked impacts from raw material extraction through transport to the factory gate. Cement tiles are made in three layers pressed in an inverted mould: a decorative top layer rich in pigments and white cement, a middle binder layer of Portland cement and sand, and a thicker base of cement mixed with crushed stone dust. After hydraulic pressing, the tiles cure naturally in air and water, a process that requires no kiln and therefore has a low direct energy demand, limited mainly to electricity for concrete mixers and factory lighting.

EcoAudit, integrated into the Granta EduPack software, works very differently. It draws on standardized internal databases to deliver rapid estimates of carbon footprint and energy consumption, making it attractive for early-stage design decisions when time, money or data are limited. The research team reconstructed the inventory for one square metre of tiles from the reference LCA, mapped each material to the closest equivalent in the EcoAudit database, and ran the simulation. Where exact materials were unavailable, approximations were needed: red pigment was replaced with titanium dioxide, ordinary Portland cement stood in for the CP-II-E and CP-II-F cement types, and quartz sand, marble dust and other aggregates were approximated by their parent rock types such as sandstone, slate and marble.

The comparison revealed a consistent pattern. Both approaches identified raw material extraction as the dominant contributor to environmental burden. In the EcoAudit simulation, the materials phase accounted for 78.2 percent of embodied energy for Factory A, 80.9 percent for Factory B and 81.9 percent for Factory C, and for 89.1, 87.3 and 90.1 percent of carbon dioxide equivalents respectively. The reference LCA showed the same hierarchy, with materials responsible for 84.7, 74.9 and 86.0 percent of relative embodied energy and 93.6, 84.6 and 97.5 percent of relative carbon dioxide emissions across the three factories. Given the methodological gulf between the two approaches, the authors judged these findings comparable mainly in relative terms.

The absolute numbers told a different story. For Factory A, the reference study reported 57.8 megajoules per square metre for materials and 10.3 megajoules per square metre for transport, whereas EcoAudit predicted 85.3 and 22.1 megajoules per square metre, 47.5 percent and 115.0 percent higher respectively. Overall, EcoAudit embodied energy estimates exceeded the reference LCA by 60.0 percent for Factory A, 112.0 percent for Factory B and 121.0 percent for Factory C, while carbon dioxide estimates were 53.0, 78.0 and 65.0 percent higher. According to the software’s own guidance, only differences greater than 20 percent are considered meaningful, and these deviations far exceeded that threshold.

The researchers traced much of the discrepancy to the proxy substitutions demanded by the EcoAudit database. A key example was marble dust, present in the inventories of Factories B and C. In the reference LCA, marble dust was treated as an industrial by-product and assigned no production-related embodied energy or carbon dioxide, contributing only through transport. EcoAudit, however, modelled it as marble, likely attaching a direct material burden. Differences in transport modelling also mattered: the reference study used fixed emission factors of 1.62 megajoules per tonne-kilometre for road freight and 0.13 for ocean shipping, while EcoAudit applied its own datasets for a 7.5 to 16 tonne Euro 5 truck and a sea container ship. The authors caution that these proxy choices introduce uncertainty that is difficult to quantify within the software interface, particularly when the original material is a by-product or a minimally processed aggregate.

To test whether the screening results remained consistent with independent data, the team also estimated the carbon footprint of the cement fraction alone using literature values. They applied a clinker emission factor of 0.9 kilograms of carbon dioxide per kilogram of clinker reported for Brazil by Petroche and Ramirez, combined with the clinker content ranges defined in the Brazilian standard ABNT NBR 16697:2018. Because no plant-specific clinker compositions were available, the midpoint of each normative range was adopted. These literature-based estimates followed the same ranking as both the reference LCA and EcoAudit: Factory B, which uses CP-III 32 RS cement with the lowest adopted clinker fraction, had the lowest cement-related impact, followed by Factory C with CP-II-F 32 and Factory A, which combines high cement demand with white cement carrying the highest emission factor. Deviations from the reference study were modest, at 2.0, 12.0 and 8.0 percent for Factories A, B and C, while EcoAudit’s deviations were larger at 28.0, 21.0 and 22.0 percent.

The cement analysis underscored why the material dominates. Cement accounted for approximately 91, 74 and 74 percent of material-related carbon dioxide emissions in the EcoAudit results for Factories A, B and C, while in the reference LCA, white and regular cement together represented more than 96 percent of the materials-stage emissions. Clinker, the reactive core of Portland cement, is produced by calcining calcium carbonate at temperatures near 1450 degrees Celsius, releasing substantial carbon dioxide and consuming large amounts of thermal energy. Globally, the International Energy Agency estimated cement-related carbon dioxide emissions at 2,324 megatonnes in 2024, against total energy-related emissions of 38.2 gigatonnes, underlining the stakes of getting cement accounting right.

The authors conclude that EcoAudit is genuinely useful for early-stage environmental screening, hotspot identification and comparing relative trends, correctly flagging Factory B as the least impactful option for carbon footprint. But they are equally clear that it cannot substitute for a full LCA when accurate quantitative indicators are needed, especially for materials with heterogeneous compositions and artisanal production routes like cement tiles. The comparison was explicitly framed as a screening-level evaluation rather than a test of methodological equivalence with ISO 14040 and 14044-compliant assessment. For designers weighing material choices in the earliest phases of a project, simplified tools can narrow the field quickly; for reliable environmental data, the full assessment remains indispensable.

Subject of Research: Comparative life cycle assessment of cement tiles using a full LCA and the simplified EcoAudit screening tool

Article Title: Early-stage comparative life cycle assessment of cement tiles

Article References: Ristow, R., Fava, E., De Noni, A., Jr, & Hotza, D. (2026). Early-stage comparative life cycle assessment of cement tiles. Discover Civil Engineering, 3(1), Article 267. https://doi.org/10.1007/s44290-026-00664-y

Image Credits: AI Generated

DOI: 10.1007/s44290-026-00664-y

Keywords: cement tiles, life cycle assessment, EcoAudit, embodied energy, carbon footprint, Portland cement, clinker, construction materials, Granta EduPack, sustainable building, cradle-to-gate, Brazil