STUDENT SPOTLIGHT: Each month, or every other month, a student will provide a 1-page illustrated abstract of the research they are currently conducting. This is a wonderful opportunity for the student, for our International Society for Concrete Pavements (ISCP) Members, and for the transferring and sharing technology/research through our concrete paving industry.
The ISCP “STUDENT RESEARCH SPOTLIGHT” for December 2025 is Beng Wei Chong, a PhD candidate in the Materials Science, Engineering, and Commercialization (MSEC) program at Texas State University (San Marcos, USA).
BIO:
Beng Wei Chong is a PhD candidate in the Materials Science, Engineering, and Commercialization (MSEC) program at Texas State University. Before joining Texas State, he earned his bachelor’s and master’s degrees of Civil Engineering from Universiti Malaysia Pahang. His research focuses on cement chemistry, alternative cement, and bioconcrete. He completed a research project on using waste eggshell as an alternative supplementary cementitious materials in concrete funded by the CREATE University Transportation Center of Texas State University. His current dissertation involves developing a novel bio-composite that is strong, lightweight, and recyclable.
TITLE: Valorization of Waste Eggshell in Portland Cement Concrete
Durability issues in concrete pavements often originate from the degradation of the cement paste or the interfacial transition zone due to environmental or chemical attack. The use of supplementary cementitious materials (SCMs) provides an effective approach to enhance durability by refining the microstructure, reducing permeability, and improving resistance to deleterious reactions. SCMs also contribute to long-term strength gain. This study aims to valorize waste eggshells as an SCM for producing blended cement, offering a more sustainable alternative to conventional portland limestone cement (PLC). Waste eggshell is an abundant resource as the U.S. is one of the leading producers and consumers of eggs in the world. In the poultry industry, waste eggshells are constantly sent to the landfill, but the waste is increasingly rejected by landfill owners due to various complications. Waste eggshells attract insects and vermin, and release harmful gases upon decomposition, posing dangers to public comfort and health.
In this study, waste eggshells were sourced from an egg-breaking plant and ground into fine eggshell powder. Detailed material characterization revealed that the eggshell powder contains similar elemental and mineralogical compositions as limestone; however, minor traces (6% by weight) of organic residue were found. Figure 1 displays a scanning electron microscopy (SEM) image showing that the eggshell powder consisted of organic layers adhering to calcium-rich particles. The hydration mechanism of blended cement pastes with 15% and 35% eggshell powder was studied. Quantitative X-ray diffraction (QXRD) analysis of the blended cement pastes showed that the phase composition of limestone and eggshell blended cement pastes was similar to each other, as shown in Figure 2. Meanwhile, isothermal calorimetry results showed that the hydration rate of 15% eggshell cement paste was similar to limestone cement paste, but the 35% eggshell cement paste had delayed hydration. In the mortar samples, significant strength drop was observed for the mortar with 35% eggshell cement compared to that containing 35% limestone.
Figure 1: SEM image of eggshell powder particle showing organic layers adhering to bright calcium-rich particles.
Figure 2: Phase composition of OPC, limestone cement, and eggshell cement pastes with no significant in structural buildup observed between cement paste with limestone and eggshell powders.
To address the negative influence of the organic impurities, the eggshell powder was washed, and two additional batches were heat-treated at 300°C and 500°C for 2 hours, respectively. The application of heat treatment denatured the organic content within the eggshell powder and was proven to be effective at mitigating the delayed hydration and strength loss. The isothermal calorimetry result of cement pastes with 35% limestone and eggshell powder after the treatments is shown in Figure 3. It is clear that the delayed hydration rate of 35% eggshell cement paste was largely mitigated after the 500 °C heat treatment of the eggshell powder. In addition, significant compressive strength improvement was observed in the mortar test, with the 35% eggshell cement mortar achieving similar strength to the 35% limestone cement mortar.
Figure 3: Isothermal calorimetry results of cement paste with 35% limestone, eggshell, and treated eggshell (a) heat flow curve (b) cumulative heat flow
In conclusion, waste eggshell powder demonstrates strong potential as a supplementary cementitious material for applications such as concrete pavements, exhibiting performance comparable to that of limestone cement concrete. The valorization of waste eggshell contributes to efficient resource utilization in construction while providing an effective solution to the disposal of waste eggshells from the poultry industry.
References:
Chong, B. W., Gujar, P., Shi, X., & Suraneni, P. (2024). Assessment of waste eggshell powder as a limestone alternative in portland cement. Materials and Structures, 57(10), 219. https://doi.org/10.1617/s11527-024-02478-9
Chong, B. W., Gujar, P., Shi, X., & Suraneni, P. (2025). Valorization of waste eggshell as a limestone alternative for high-volume incorporation in portland cement. Journal of Materials in Civil Engineering. In press.
ISCP would like to feature a “STUDENT RESEARCH SPOTLIGHT” each month, or every other month. If you would like to nominate a student, or if you are a student and would like to nominate yourself or a colleague, please send ISCP an email to: newsletter@concretepavements.org