Using industrial byproducts to replace cement is an important way to reduce carbon emissions from the cement industry. In this study, the effects of two industrial byproducts, fly ash (FA) and quartz powder (QZ), as supplementary cementitious materials (SCMs) on the macroscopic properties and microstructure of cement-based materials were experimentally investigated. The results of the compressive strength and ultrasonic pulse velocity experiments showed that QZ significantly mitigated the decrease in strength and ultrasonic pulse velocity caused by the reduction in cement dosage in the early stage. Moreover, the 28-day compressive strength of the FA group was comparable to that of the control group, and regression analysis indicated a negligible effect of FA addition on 28-day compressive strength. X-ray diffraction and Fourier transform infrared spectroscopy experiments showed that QZ can promote the hydration reaction in the early stage. Scanning electron microscopy images revealed that a layer of hydration products can form on the surface of FA after 28 days of hydration. Hydration heat experiments indicated that FA significantly reduces the release of hydration heat, while QZ promotes the formation of ettringite through nucleation effects in the early stage of hydration, thereby accelerating the release of hydration heat. Thermogravimetric analysis after 28 days showed that the amount of hydration products and calcium hydroxide produced decreased with the addition of cementitious materials. Finally, the use of FA and QZ was analyzed for carbon emissions and energy consumption. The results showed that using these two cementitious materials significantly reduces carbon dioxide emissions and energy consumption.

Coal is still China’s primary energy source, and the production process of coal produces industrial byproduct coal gangue. This study explores the possibility of using industrial byproducts of thermal power generation, fly ash (FA) and calcined coal gangue (CCG), as a partial (10% and 20%) substitute for cement in construction materials. Methodical research was conducted to determine how these two substances affect the microstructure and macroscopic characteristics of cement-based materials. Macroscopic performance test findings indicate that replacing 20% of cement with CCG had no discernible effect on the specimens’ performance. At the same time, adding FA required 28 days to be comparable to the control group. Mercury intrusion porosimetry (MIP) test results show that using CCG can refine microscopic pores. Additional hydration products could be produced by these materials, according to analyses using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The production of hydration products by CCG to fill the microscopic pores was further demonstrated by scanning electron microscopy (SEM) pictures. After 28 days of hydration, a layer of hydration products developed on the surface of FA. When supplementary cementitious materials (SCMs) were added, calcium hydroxide (CH) was consumed by interacting with FA and CCG to form additional hydration products, according to thermogravimetric analysis (TG) data after 28 days. Furthermore, an evaluation of FA and CCG’s effects on the environment revealed that their use performed well in terms of sustainable development.