## 1 Introduction  
In the last decade, the acceleration of urbanization has led to a sharp rise in the production of construction and demolition wastes (C&DW) in China, and the annual production of waste concrete is up to 20 billion tons. These ever-increasing C&DW pose serious challenges to environmental governance [1; 2; 3]. Meanwhile, China's construction raw materials, such as sand and stone, have been overexploited [4; 5]. The preparation of recycled aggregate concrete (RAC) by replacing the natural aggregate (NA) with recycled aggregate (RA) from waste concrete can solve the dual problems of environment and resources effectively. The application of RAC is of great significance to the sustainable development of concrete [6; 7; 8]. Extensive research on mechanical and durability of RAC has been carried out in recent years [9; 10; 11]. Most scholars suggest that RAC is weaker than natural aggregate concrete due to the higher water absorption and crushing index of RA [12; 13]. Some articles also reported that the complex and weak interface transition zone (ITZ) in RAC is also an important factor resulting in the performance deterioration of RAC [14]. However, the performance of RAC can be conformed to the specific requirements through reasonable design or adjustment of mixing ratio, and RAC has some applications in the construction industry [15; 16; 17]. The masonry structure is composed of blocks that are the oldest building materials, and this form of structure has been widely employed in the world [18]. The combination of RA with the masonry structure is absolutely inspiring. The RAC has certain advantages in block production compared with that in components, which is attributed to the block production technology. Several studies have reported that the process of vibrating and compacting can make up for the disadvantage of RAC slump, making the RAC block have a higher strength [19]. In addition, the reduced water content used in the block production process will significantly reduce the creep and shrinkage of RAC [20]. There have been some reports on recycled concrete bricks in recent years. [PERSON] et al. [21] carried out the study on compressive of RAC bricks, and noticed that the compressive strength of the brick is almost constant with the RA replacement ratio of 50%, but the higher the replacement percentage, the lower the compressive strength of the paving slab. [PERSON] et al. [22] investigated the effect of water-cement ratio and aggregate type on the performance of paving concrete blocks. They reported that the compressive strength of paving slabs decreases as the water-cement ratio increases and is proportional to the crush index of the aggregate. The effect of recycled aggregate on the compressive strength of precast concrete hollow blocks was reported by [PERSON] et al. [19], which determined the content of RA in blocks with appropriate compressive strength. However, a few contrary conclusions have been proposed by [PERSON] [23]. It can be found that from the above description, most of the current research involves the mechanical properties of RAC paving slabs. However, there are few reports on the use of RCA to manufacture blocks for buildings. This is disappointing for the promotion and application of recycled concrete block masonry structures. In this paper, three groups of RAC specimens with different replacement ratios of recycled aggregate (0%, 50%, 100%) were prepared. The mechanism of the block and mortar properties on the compressive strength of RAC block masonry were investigated by means of static loading test. Moreover, the global warming potential (GWP) of RAC block masonry was evaluated by life cycle assessment (LCA) methodology. The feasibility of application of RAC block masonry was discussed. It can be inferred that the compressive strength of RAC block masonry increased regularly with the strength of the RAC block being enhanced, and the effect law of mortar performance was similar.