There is a huge reservation of loess in the Shanxi mining area in China, which has great potential for preparing supplementary cementitious materials. Loess was modified via mechanical and thermal activation, and the pozzolanic activity was evaluated using an Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). Moreover, the workability of grouting materials prepared using modified loess was assessed. The experimental results revealed that the number of ultrafine particles gradually increased with the grinding time, enhancing the grouting performance. The coordination number of Al decreased upon the breakage of the Al-O-Si bond post-calcination at 400 degrees C, 550 degrees C, 700 degrees C, and 850 degrees C. Moreover, the breaking of the Si-O covalent bond produced Si-phases, and the pozzolanic activity of loess increased. Furthermore, the modified loess was hydrated with different cement proportions. With increasing grinding time, the overall setting time increased until the longest time of 14.5 h and the fluidity of the slurry decreased until the lowest fluidity of 9.7 cm. However, the fluidity and setting time decreased with increasing calcination temperature. The lowest values were 12.03 cm and 10.05 h. With the increase in pozzolanic activity, more ettringite was produced via hydration, which enhanced the mechanical properties. The maximum strength of the hydrated loess after grinding for 20 min reached 16.5 MPa. The strength of the hydrated loess calcined at 850 degrees C reached 21 MPa. These experimental findings provide theoretical support for the practical application of loess in grouting.

With the widespread use of geopolymer, the effective activation and utilization of thermally activated termite soils as alternative or eco-friendly material are great of interest. The present study investigated the use of calcined termite soils (TC) in geopolymer pastes and mortars as a precursor, while metakaolin (MK) was used as a reference material to prepare control samples. The physicochemical properties of both raw and calcined solid precursors as well as geopolymer pastes and mortars were characterized using various techniques, including BET, PSD, XRF, XRD, setting time, ICC, and SEM/EDS. Results showed that termite soil can be successfully employed as a starting material in geopolymer production. Pastes and mortars prepared using TC gave significant compressive strengths of 43.2 and 33.2 MPa, respectively, although they were approximately 26% and 6% lower than control samples made using MK. Based on the analytical studies, better mechanical performance of MK-based binders compared to TC-based ones is attributed to the presence of reactive phases within MK that promotes the geopolymerization resulting in the development of a stronger geopolymer network and better connectivity within the matrix. It can be concluded that TC can be considered as a suitable raw material for the production of geopolymer binder considering the availability and accessibility in certain regions.