This study uses sludge, which is a by-product of the light-emitting diode (LED) manufacturing process
and an industry waste (called LED sludge), to replace some weight percentage of cement. The LED sludge
powder was used to replace 5, 10, 20, and 30 wt.% of the cement, and the (5  5  5-cm3) sludge-blended
cement mortar (SBCM) specimens were molded for a compressive strength test and other engineering
property tests. The properties of the LED sludge sample were checked using a scanning electron microscope/
energy dispersive X-ray spectrometry (SEM/EDS) analysis, an X-ray diffraction (XRD) analysis,
and a solid-state nuclear magnetic resonance spectroscopy (NMR) analysis. The compressive strength test
shows that the SBCM specimens have comparable compressive strength relative to ordinary Portland
cement mortar (OPCM) specimens in the early curing age of 1–7 days, and 103–115% of the compressive
strength of OPCM specimens after curing for 14–90 days. The test results reveal that the nano-particles
promoted the pozzolanic reaction and enhanced the strength evolution. LED sludge can be converted into
a useful resource by exempting the difficulty of disposal problems and appealing to the environmental
sustainability.