Design and performance of fiber-optic light-transmitting cementitious composites

Abstract

The integration of optical fibers into cementitious matrices offers a promising way for developing materials that combine structural performance with optical functionalities, enabling applications in architectural daylighting, sensing, and information transfer. The subject remains fragmented, with inconsistencies in terminology, experimental methodologies, and interpretation of results, limiting the development of unified design approaches and challenging comparison across studies. This thesis investigates fiber-optic cementitious composites by relating material design, optical behavior, and mechanical performance within a unified framework, using a combined experimental and analytical approach. First, the reliability of optical transmittance measurements is evaluated by analyzing the influence of experimental configuration, particularly the detector-sample distance. Experimental results show that measurement conditions significantly affect reported transmittance values, contributing to variability across studies. To address this, a physically grounded methodology based on the spatial distribution of light emerging from embedded optical fibers is developed. This approach provides a consistent basis for optical characterization and improves measurement reproducibility, thus proposing a practical contribution toward standardization in the field. Second, the mechanical behavior of composites containing embedded optical fibers is investigated through comparative experimental analysis. Samples with fibers are evaluated alongside samples containing preformed holes of equivalent geometry, enabling the separation of material and geometric effects. The results show that both fiber-matrix interaction and geometric disruption influence the mechanical response, with their relative contributions depending on loading conditions and matrix composition. Finally, to extend the functionality of these materials beyond passive light transmission, alternative fiber configurations are explored. A composite with randomly distributed optical fibers is developed, demonstrating that light propagation can be modified to achieve visual privacy while maintaining light transmission. A computational reconstruction approach further demonstrates that information scrambled by the random fiber arrangement can be digitally recovered, positioning these composites as hybrid physical-digital systems. Overall, this work provides a coherent understanding of fiber-optic cementitious composites by linking optical characterization, mechanical behavior, and material design, and establishes design principles for multifunctional cementitious materials integrating optical and structural performance with emerging digital capabilities.

Date	9 Sept 2026
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Claudiane Ouellet-Plamondon (Supervisor) & Bora Ung (Co-supervisor)