Effect of ceramic waste tile as a fine aggregate on the mechanical properties of low-carbon ultrahigh performance concrete. (17th March 2023) - Zhang, Liqing
Highlights: Low-carbon UHPC can be fabricated using 100% ceramic waste tile aggregates (CTWA). Low-carbon UHPC incorporating large content of CTWA shows higher mechanical properties and acceptable workability. Internal curing and better particle gradation of CTWA enhances the mechanical properties of low-carbon UHPC. Abstract: Overmining of sand from natural resources has seriously impacted the environment, hindering the sustainable development of concrete. Ceramic waste tile has a chemical component similar to that of sand and can be a potentially excellent substitute for sand. Therefore, this study uses 20 %, 40 %, 60 %, 80 %, and 100 % ceramic waste tile aggregate (CTWA) to replace sand in equal amounts to produce low-carbon ultrahigh performance concrete (UHPC). The workability and mechanical properties of UHPC with varying CTWA content is explored. Additionally, the interface transition area (ITZ) and pore structure of UHPC are characterized by scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP), respectively. Finally, the modified Andersen and Andresen (MAA) model is employed to evaluate the effect of CTWA on the UHPC packing compactness. The results show that the incorporation of CTWA reduces the flowability of UHPC. However, the spread flow for UHPC with 100 % CTWA can also reach a value of 398 mm. The UHPC with 100 % CTWA exhibits better mechanical properties, as reflected by an improvement in compressive strength and flexural strength of 15.5 % and 26.5 %, respectively, at a curing age of 28 d. Moreover, the addition of CTWA shows no significant negative effect on the fracture toughness of UHPC. Microstructure analysis demonstrates that the ITZ and pore structure of UHPC with CTWA are effectively improved due to the internal curing and better particle gradation of CTWA. Therefore, CTWA, with economic and environmental advantages, is a practicable alternative fine aggregate for UHPC.