## 1 Background and Significance  
The increase in body length, area, or volume as temperature rises is known as thermal expansion [1]. The change in length with temperature for a solid body may be expressed as the linear coefficient of thermal expansion (CTE); [2, 3, 4] it is a material property that is indicative of the extent to which a material expands upon heating [5]. This occurs because the material's atoms and molecules have an increased average kinetic energy, which causes their distance from one another to grow. Most solid materials expand upon heating and contract when cooled. This thermal behavior is important in construction materials like concrete since temperature-induced dimensional changes can lead to strains and possible cracking. Concrete, while widely used in construction material, is prone to cracking due to its brittle nature, especially under tensile stress. This stress can arise from various factors such as thermal stress, shrinkage, and mechanical loads [6]. Concrete is a heterogeneous material, and its properties are influenced by its constituent characteristics like cement paste, aggregates, moisture content, and age. It is also influenced by environmental factors like temperature variations and relative humidity [1, 7]. Every time concrete is exposed to a temperature change, the concrete's CTE causes deformations in unrestrained concrete structures. An increase in the CTE value results in an increase in the international roughness index (IRI), which is directly related to slab cracking and joint faulting [8]. When the deformations are limited, thermal stress arises. The magnitude of thermal stress is influenced by the temperature change, CTE, material modulus of elasticity, and degree of concrete member constraint [9]. In the case of concrete, several variables, including internal relative humidity (RH), mixture ingredient characteristics, moisture level and degree of hydration (age), affect it [10; 11]. A dense concrete block's CTE is typically \(10\ ^{-5}/^{\circ}\)C [12; 13], and concrete with CTE with an average value of \(9.9\times 10^{-6}/^{\circ}\)C is considered suitable for pavement design [14]. The CTE values have a significant influence on the design and analysis of rigid pavements despite being quite small [15]. CTE is a crucial factor since temperature gradient not only impacts the pavement's longitudinal features, but it can also result in deformation along the slab's thickness [8]. To optimize concrete joint design, calculate stresses, design joint sealants, and choose sealant materials, the CTE is a crucial consideration in rigid pavement design. Considering the thermal behavior of concrete, the composite coefficient of thermal expansion of concrete is obtained by using the CTE value of two primary components of concrete, mortar and coarse aggregate [16]. Typically, the paste's CTE is significantly higher than the aggregate's. The value of CTE for aggregates differs based on aggregate minerology and typically ranges from 4 to \(13\times 10^{-6}/^{\circ}\)C, and cement paste typically has values between 11 and \(20\times 10^{-6}/^{\circ}\)C [13; 17]. The volumetric percentage of the aggregate in the mix might affect the CTE of concrete since cement paste typically has a greater CTE than aggregate. Ref [18] recommended using materials with lower CTE, optimizing the mix proportions of concrete to reduce cement paste and increase coarse aggregate content, and using dense concrete with high elastic modulus. The objective of this review paper is to provide a comprehensive understanding of concrete CTE, its significance in pavement design, and the factors that influence it, while exploring experimental methods and recent advances in the area. By providing a comprehensive review of CTE, this paper critically examines measurement techniques, focusing on integration with modern design approaches, emphasizing the interplay of influencing factors, and directly linking CTE to pavement performance.