Influence of Mix Constituents on the Printability and Compressive Strength of Binary and Ternary Cementitious Composite Made of Agro-Industrial Waste (2026-04)¶

In today’s world, three-dimensional concrete printing (3DCP) technology has seen increased popularity owing to its improved advantages, such as rapid construction and better structural efficacy, among others, over conventional concreting. However, the lack of understanding about designing a concrete mix with respect to both printability performance and hardened mechanical properties is one of the barriers behind its large community acceptance. Moreover, if such a 3D-printable concrete mix with desired properties can be designed in an environmentally friendly manner, that would further enlighten the importance of 3D printing in construction. Hence, in this study, bagasse ash (BA) and fly ash (FA) are utilized, and sustainable, greener, 3D-printable binary [ordinary portland cement (OPC) and BA] and ternary (OPC, BA, and FA) concrete mixes are designed with a targeted concrete grade of M30. Consequently, various trial mixes are designed incorporating different proportions of BA and FA, along with the combination of other components such as superplasticizer (SP), viscosity modifying admixture (VMA), and retarder to achieve maximum cement replacement while maintaining the desired printing performance and hardened properties of the developed binary and ternary cementitious binder. With respect to different printing parameters and hardened properties, respective tests are conducted to determine the pumpability, extrudability, buildability, open time, and compressive strength of the various designed mixes. The results demonstrated that up to 40% of the cement can gainfully be replaced with BA in fabricating 3D-printable binary binder for a targeted compressive strength of concrete of M30 grade. Whereas, in the case of the ternary mix, cement–BA–FA at a ratio of 60∶20∶20 is found to have better extrudability and buildability than the binary mix for the same compressive strength.