This study investigates the potential of graphene-based additives to improve the mechanical properties of compacted soil mixtures in rammed-earth construction, contributing to the development of environmentally friendly building materials. Two distinct soils were selected, combined with sand at optimized ratios, and treated with varying concentrations of a graphene liquid solution and a graphene-based paste (0.001, 0.005, 0.01, 0.05, and 0.1 wt.% relative to the soil-sand proportion). The effects of these additives were analyzed using the modified Proctor compaction and unconfined compressive strength (UCS) tests, focusing on parameters such as optimum water content (OWC), maximum dry density (MDD), maximum strength (qu), and stiffness modulus (E). The results demonstrated that graphene's influence on compaction behavior and mechanical performance depends strongly on the soil composition, with minimal variation between additive types. In finer soil mixtures, graphene disrupted particle packing, increased water demand, and reduced strength. In silt-sandy mixtures, graphene's hydrophobicity and limited interaction with fines decreased water absorption and preserved density but likewise led to diminished strength. Conclusions from the experiments suggest a possible interaction between graphene, soil's finer fraction, and potentially the swelling and non-swelling clay minerals, providing insights into the complex interplay between soil properties.

The interest of reinventing raw earth is for the purpose of drastically reducing the environmental impact of the continuous human urban growth. This paper discusses the use of cellulose synthesized by bacteria as a new source of microfibers to reinforce the soil matrix. It presents firstly, the bacterial cellulose (BC) and its production method then it focuses on defining its microstructural characteristics. In the second part, the soil-BC association is studied. Commercial soil (DW-earth) and bentonite clay were tested with 3 and 8% of BC. The objective is to evaluate the impact of BC addition on the soil's physcio -mechanical properties. Shrinkage and mechanical performance tests were carried out. The results showed a material with better mechanical performances and high cracks resistance. The shrinkage percentage decreased significantly for DW-earth with a similar water/solid ratio when adding BC, by about 18 and 22% when adding 3 and 8% BC for water content of 35%. In the case of bentonite clay the BC addition has only a positive impact on limiting cracking. The mechanical tests showed that 8% of BC increases the compressive strength of the cylindrical specimens by + 28 and + 649%, respectively for the DW-earth and bentonite clay, whereas the flexural strength of the prismatic specimens increases by + 39 and + 556%.

As a significant symbol of human civilization advancement, earth construction not only inherits traditional architectural culture but also enjoys worldwide popularity and widespread usage throughout China due to its economic and environmentally friendly nature, as well as its moisture absorption and heat storage advantages. Consequently, earth construction has garnered considerable attention from international scholars. This paper compiles relevant data to review the developmental trajectory of earth construction, while conducting an in-depth analysis of the performance characteristics of earthen materials. Furthermore, it provides a comprehensive overview of the impact of three modification methods on the mechanical and durability properties of earthen materials, along with a discussion on the research concerning the thermal and moisture performance of these materials. Simultaneously, discussions were held on the relevant research findings and potential directions for the development of earthen materials. Finally, conclusions were drawn, suggesting a comprehensive utilization of their thermal and moisture performance, emphasizing the enhancement of their mechanical and durability performance. Additionally, attention was urged towards the economic and ecological aspects during the construction and maintenance phases of earth construction. These recommendations aim to facilitate the sustainable development and widespread application of earthen materials in the future.