Mechanical, permeability, and optical properties of concrete integrating light-transmitting materials with high contents and large diameters

The present study focuses on developing LTC panels with high light transmission efficiency by integrating optical fibers or Polymethyl Methacrylate (PMMA) rods at volumes of 10–30% into the concrete. This aims to enhance the percentage of light intensity transmitted through the LTC to approximately 30% from the light source, a significant improvement compared to most previous studies where it was below 10%. Various configurations of these materials, differing in diameter and volume, were tested for their effects on mechanical strength, permeability, and optical properties. Unlike most previous studies using optical fibers smaller than 2.0 mm, the findings indicate that using optical fibers or PMMA rods with larger diameters improves the feasibility of casting LTC panels with ultra-high light transmission capacity and compressive strength above 40 MPa. The mechanical strength of LTC samples can be predicted based on the effective cross-section, excluding the area occupied by light-transmitting materials. The study also reveals that larger PMMA rods increase permeability due to weaker bonds with the surrounding concrete. Additionally, LTC panels can transmit colors and images without altering the original light source color, highlighting LTC’s potential for creative applications, such as smart traffic signal displays on pavements or unique architectural designs.