## 1 Introduction
[PERSON] and [PERSON] [8] examined the feasibility of producing new concrete with crushed brick as coarse and fine aggregate, considering 25%, 50% and 75%, 100% replacement rates of fine and coarse aggregate by the crushed brick, respectively. The results and mechanical performances were evaluated by the water absorption, water permeability, shrinkage, compressive strength, flexural strength and modulus of elasticity. The authors found that the compressive strength at 28 days decreased with the replacement rate. [PERSON] et al. [16] evaluated the properties of concrete blocks made with low-grade RA They determined (i) the compressive strength of specimens with 100% natural fine aggregate content in the concrete. (ii) With an aggregate-cement ratio of 10:1, the 14 days drying shrinkage value of specimens at the \(<\)50% particle fine aggregate substitution level satisfied the requirement (0.06%). It was also indicated that when the recycled fine aggregate content or aggregate-cement ratio decreases, the drying shrinkage value of the concrete block also decreases. (iii) Due to the higher mud content in RFA, the compressive strength reduction level decreases after exposure to high temperatures, which can be explained by the formation of a new crystalline phase: calcium aluminum. [PERSON] et al. [17] considered the replacement percentage of coarse aggregate including all particle sizes in the aggregate combined with all particle sizes of NA. The results showed that (i) the compressive strength of the concrete made by the new method could be increased up to 50% and the amount of RA in concrete was 5.3% higher than the 30% of RA that is contained in concrete made by conventional methods. (ii) The splitting tensile strength improved by 2-5% compared to the conventional combination. (iii) The modulus of elasticity improved by 20% compared with the conventional combination, and the Poisson's ratio was 0.2 with 30% RA, which satisfies the requirement. (iv) With RAC substitutions of 30%, 50% and 70%, it was observed that the peak strain of RAC increased by 10% in the stress-strain curve. In addition, the qualities of the mortars, the interfacial transition zone (ITZ) and the adhered mortars of recycled aggregate have effects on the recycled aggregate concrete's properties Someauthors have conducted similar studies [9; 10; 11]. [PERSON] [9] observed that at low water-cement ratios, the strength of the RAC depends on the effect of the old ITZ, while at higher water-cement ratios, the strength of the RAC is determined by the water-cement ratio. Moreover, [PERSON] et al. [10] studied the effects of recycled aggregates different amounts of old adhered mortars on the mechanical performance of the RAC. Due to the adherence of the original cement mortars on the surface of the aggregate, the bonding between the old aggregate block and the new cement could be improved. It has been indicated that the ITZ would improve because of the rough surface of the RA. [PERSON] et al. [11] investigated the properties of various RA/paste ITZ in concrete and revealed that the elastic modulus of the ITZ depends on the relative contents of the various constituent materials contained in the recycled aggregate. Currently, there is a demand for experiments to be conducted to obtain a reasonable mix ratio to attain the expected requirement strength of RAIW made of recycled crushed clay brick and concrete block. Some scholars have conducted in-depth studies on recycled aggregate concrete from different aspects. [PERSON] et al. [19] evaluated the feasibility of producing non-structural partition wall blocks with crushed clay brick aggregates. It was observed that the combination of different types of fine aggregates allowed better compressive strength to be obtained, and the flexural strength reached its maximum at a level of 75% of crushed clay fine aggregates. Due to fine particles filling the voids and diminishing the porosity of the concrete the compressive strength enhanced.