Precast concrete is an alternative material that can be used in mass quantities and controlled quality for earthquake-resistant, fast-building houses. For the installation and transportation process, precast concrete must be lightweight and have a high initial compressive strength. One solution to these development needs is expanded clay structural lightweight concrete. The purpose of this research is to produce lightweight expanded clay structural concrete with a high initial compressive strength, a maximum specific gravity of 1750 kg/m3, a minimum initial compressive strength of 14 MPa at 1 day, and a minimum compressive strength of 20 MPa at 28 days. Indicators such as internal curing, steam curing, superplasticiser, and accelerator produce higher compressive strength. The results of this study indicate that structurally expanded clay lightweight concrete with steam curing could achieve an initial compressive strength of 16.23 MPa at 1 day. Using an accelerator to maximise the compressive strength of expanded clay lightweight concrete was effective at 10% of the water volume, resulting in an initial compressive strength of 21.64 MPa at 1 day and a specific gravity of 1,722 kg/m3.