The traditional interlayer bonding testing methods used for cement-based materials is not suitable for three-dimensional (3D)-printed geopolymers and they have some drawbacks that prevent efficient and accurate testing; accordingly there is an urgent need for a new testing method. In this briefing article, a newly designed fixture method (N-FM) was proposed to test the interlayer bonding strength of a 3D-printed geopolymer made from TJC-1 lunar regolith simulant as a case to show the improvement from the previously used traditional adherence method (T-AM). The results show that these two methods exhibit different failure modes. Interlayer failure, intralayer failure and epoxy resin detaching can be observed from the T-AM, while interlayer failure and diagonal failure can be observed from the N-FM. Compared to 50% by the T-AM, the success rate can be improved up to 90% by the N-FM and the distribution of data is more uniform. The 28-day interlayer bonding strength result from the N-FM was 2.16 MPa, which is considered to be more accurate, and is 30.91% higher than that of the T-AM.
Hu et al. (2026) studied this question.