The potential of fluorescent light tube powder as a sustainable partial cement replacement for mortar

Fluorescent light tubes are an economical source of light. However, when they cease to emit light, they become waste tubes. These waste tubes can easily break into small particles that are non-degradable, posing significant waste management challenges. Furthermore, waste tube particles are hazardous to human health and release harmful gases when burned. To address this issue, ground waste tube powder (WTP) was utilized in cement mortar—a novel approach not previously reported in the literature. The mortar was prepared with a water-to-cement ratio of 0.35 and a cement-to-sand ratio of 1:1. WTP was incorporated as a partial replacement for cement at levels of 0 %, 2.5 %, 5.0 %, and 7.5 % by weight to evaluate its effects on the mortar properties. The mortar was mixed using a mortar mixer (J-type: 10-L capacity), and each test followed the standard procedures prescribed by the relevant codes. The optimal WTP content was found to be 5.0 %, which increased the flow table value, compressive strength, elastic modulus, flexural strength, and tensile strength by 2.0 %, 16.4 %, 6.0 %, 20.8 %, and 7.7 %, respectively. Conversely, the density and water absorption decreased by 3.6 % and 43.5 %, respectively. At lower WTP contents (up to 5 %), the pozzolanic characteristics of WTP enhanced the mechanical properties. However, at higher contents, these properties decreased due to the insufficient cement particles, which were replaced by a larger proportion of WTP. The implementation of these findings not only resolves the critical problems of WT disposal but also contributes to the production of higher-quality mortar for sustainable infrastructure development.