Effect of clam shell from kitchen waste on the synthesis, performance, and hydration of cementitious clinker

The calcareous material for the synthesis of cementitious clinker is in great demand. Clam shell (CS), a calcareous solid waste from kitchen waste, causes serious harm to the environment. This work on a laboratory scale synthesized five cementitious clinkers with 0.00, 20.00, 40.00, 60.00, and 80.00 wt% CS. The baking temperature, mineral phases, and strength development of the cementitious clinker were investigated. The hydration product was studied using X-ray diffractometer, thermogravimetric analyzer, and scanning electron microscope. Results show that the baking temperature is reduced by 50 degrees C when the CS addition exceeds 40 wt%. The mineral phases of the cementitious clinker synthesized with and without CS are tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite; the hydration products are calcium hydroxide, calcium-silicatehydrate, and hydrated calcium aluminate. With the incremental addition of CS, the amount of tricalcium silicate increases but that of dicalcium silicate decreases; the amount of each hydration product increases at the same curing time, increasing the flexural and compressive strengths. The cementitious clinker synthesized with 80.00 wt% CS is the highest, which are 3.5 and 19.8 MPa at 3 days, 6.2 and 30.5 MPa at 7 days, and 9.2 and 43.9 MPa at 28 days, respectively. This work supplies an experimental basis and reference for the synthesis of cementitious clinker using CS as a calcareous material and for the disposal of CS, contributing to the protection of the community environment and the saving of the costs of raw material for the enterprise.