## 1 Introduction  
Waste tire rubber is a kind of polymeric solid waste whose volume is increasing at a fast rate. Every year, almost 1000 million tires are discarded, and 50% of them are not reused. By the year 2030, the accumulation of waste tires will reach about 1200 million, which is one of the most important ecological and environmental problems around the world. Considering that waste tires hold toxic and soluble components, this may lead to the reduction of biodiversity in landfill sites. Generally, the cheapest and easiest method for decomposing waste tires to burn them, which results in problems that harm human health and the environment [1; 2; 3; 4]. In addition, the residue powder left after burning pollutes the soil. The oil that is generated from the melting of tires also pollutes soil and water [5]. In order to make better use of waste tires, researchers have carried out some relevant studies. For example, fine shredded tire particles have been utilized in road construction and repair [6; 7]. In civil engineering, tires, cut or not, are used for building noise screens, insulation, light fillers, and bridge supports, etc. [1]. It is worth noting that the incorporation of processed waste tires into concrete by partially replacing aggregates to produce rubberized concrete is an example of reusing waste to produce a sustainable material [8]. Recycled rubber can be regarded as a sustainable alternative, as it contributes to reducing waste production and the use of raw materials [9], increases the workability of concrete, and provides environmental-friendly and cost-effective solutions by using recycled materials for concrete construction applications [10]. Although reusing waste tires for concrete production has negative effects on concrete properties such as lower compressive strength and splitting tensile strength,recycled tire rubber is a promising material in the construction industry due to its favorable lightweight, elasticity, energy absorption, sound, and heat insulating properties. In view of this, it has potential for applications in circumstances where strict crack resistance and higher flexibility but moderate or lower compressive strength (20-30 MPa) are required, such as the base layer of pavement, face slab of a rock-filled dam, and impervious barriers of reservoirs [11; 12]. Therefore, the research and application of rubberized concrete has bright prospects, which can bring high economic value and environmental benefits. Mechanical properties of rubberized concrete containing waste tire rubber particles have been investigated in many studies [13; 14; 15; 16; 17; 18]. Although the strength of rubberized concrete is reduced, some studies have revealed that mixing rubber into conventional concrete could improve its deformability and ductility, thus resulting in high fracture and cracking resistance due to rubber's good properties such as high toughness. For example, [PERSON] et al. [15] found that tire-treated aggregates reduced the mechanical strength of specimens, but enhanced ductility of materials. [PERSON] [18] found that rubberized concrete generally had a reduced compressive strength which may limit its use in certain structural applications, but it possessed some desirable properties, such as lower density, higher toughness, and higher impact resistance as compared to conventional concrete. [PERSON] et al. [19] observed that the mechanical strength of crumb rubber concrete was reduced, while durability was improved with an increase of crumb rubber content. In other words, adding rubber particles to concrete can contribute to prolonging its service life. Furthermore, compressive strength is significantly influenced by rubber content. Systematic reduction in compressive strength has been observed with the increase of rubber content [8; 20; 21; 22; 23]. For example, [PERSON] et al. [21] revealed that as the rubber content increased from 0% to 18%, the compressive strength of rubberized concrete reduced by about 31%.