Engineering performance trade-offs of glass-fiber-reinforced expanded-vermiculite lightweight mortar: Density, transport, carbon, and cost

Abstract

Lightweight mortar design requires balancing density reduction against mechanical, transport-related, environmental, and economic performance. This study evaluated a combined expanded-vermiculite–glass-fiber (EV–GF) mortar system in which expanded vermiculite replaced 10%, 20%, and 30% of the reference fine-aggregate bulk volume, while glass fiber was added as an additional constituent at a constant nominal dosage of 18 kg/m³ relative to the base-mixture design volume; M0 was the plain control. With one independent batch per formulation, oven-dry geometric density, compressive and flexural strength, structural efficiency, ultrasonic pulse velocity (UPV), permeable porosity, 91-day cumulative capillary water absorption over 240 min, qualitative SEM–EDS observations, and performance-normalized carbon and cost indicators were evaluated descriptively. Carbon-factor sensitivity and the robustness of a seven-indicator comparative screen to alternative weighting and radar-axis ordering were also examined. Density decreased from 2210 kg/m³ for M0–1644 kg/m³ for M3, but the engineering response was non-monotonic. M0 recorded the highest 28-day compressive and flexural strengths (10.46 and 2.27 MPa). Among the modified mixtures, M2 (20% expanded-vermiculite replacement) showed the most favorable measured response, with 8.25 MPa compressive strength, 1.99 MPa flexural strength, 3094 m/s UPV, 14.43% permeable porosity, and 9.2 mm cumulative absorption at 240 min. All modified mixtures had higher calculated material-stage embodied carbon than M0 under the investigated emission-factor scenarios and substantially higher corrected material costs, which increased from M1 to M3; M2 nevertheless achieved the highest SCeR and SCR among M1–M3. The ranking M0 > M2 > M1 > M3 remained unchanged across all investigated weighting scenarios and all 360 unique radar-axis arrangements. M2 was therefore the highest-ranked modified mixture within the investigated compositions and adopted criteria, not a universally optimal formulation. The results provide short-term laboratory screening and do not establish structural or long-term application suitability.

Access to Document

Other files and links

• Link to publication in Scopus
• Open Access Version Available

Fingerprint