The study investigates the effect of increasing aggregate volume on the buildability of printable mixes having ordinary Portland cement and limestone calcined clay, and aggregate-to-binder ratio of 1.5 to 3 (by weight). The experimental program is planned considering the evaluation of extrudability requirements, open time, and buildability requirements (layer compression) while printing. The effect of water-to-binder and aggregate-to-binder ratio on flowability is analysed and the dosage of superplasticizer required to attain 200 mm and 180 mm spread is determined. Further, squeeze flow and step load tests are performed to analyse the compressive resistance of the mix at different time intervals in the fresh state, while compressive strength and drying shrinkage are considered to compare the mixes in the hardened state. The factors of energy consumption and carbon emission are considered to compare the sustainability of the mixes. It is concluded that the binder-aggregate matrix governs the compression of the material in the fresh state, with the paste governing the properties in the first few minutes and then the aggregate skeleton. The compression in the fresh state is observed not to be dependent on the mix’s flowability, leading to the possibility of designing a flowable as well as buildable mix with a larger aggregate volume. Further, with an increase in the aggregate ratio from 1.5 to 3, the energy consumption of the mix reduces from 3571 to 2426 MJ and carbon dioxide emission from 462 to 314 kg CO₂ for each m³ of concrete. Hence, it is concluded that a sustainable 3D printable mix with a higher aggregate-to-binder ratio can be designed while satisfying the functional needs of the concrete.