## 1 Introduction  
The semi-rigid base material of cement stabilized macadam is widely used in road base construction in China, which has the advantage of high early strength, water stability, and frost resistance. However, the preparation method of indoor heavy compaction test and static pressure specimens are only similar to the road building machinery and technology of the 1980s, whose compaction work and mechanism of strength formation are very different from the vibratory rollers that are now widely used in road building machinery. The existing indoor test have been unable to properly guide the actual design and engineering application of cement stabilized macadam mixture. On the other hand, the purpose of molding specimens is to obtain indoor samples that are similar to the actual pavement base in the field, and to predict the performance of road base by testing the strength, modulus, and durability of the samples. However current test methods only stay on the macroscopic mechanical behavior level, and lack the mechanism from mesoscopic view. Cement stabilized macadam mixture is the multiphase inhomogeneous materials composed of coarse aggregate, cement mortar and void, but traditional empirical design methods only assume that the mixture is a uniform whole from a macroscopic perspective, which could not meet the aggregate interface behavior research [1]. In recent years, many scholars have carried out research on other indoor compaction methods, such as the Proctor method [2; 3], vibrating table tests [3], and vibration compaction molding method. In China, scholars are more committed to researching the indoor vibration compaction molding method for cement stabilized macadam, and have proved that the specimens molded by this method have higher mechanical strength, and has higher correlation with on-site samples [4; 5; 6; 7; 8; 9]. For example, the unconfined compressive strength, splitting strength, and resilient modulus of cement stabilized macadam mixture prepared by the vibration compaction method are 1.87-2.37, 1.54-2.74, and 1.53-1.96 times more than those prepared by static pressure molding and heavy compaction method, and the results show that the mechanical properties have a correlation of 91.7% with the field [4]. However, the above researches are mainly analyzed from a mechanic perspective. In fact, many properties of the mixture can also be studied by mesoscopic analysis. For example, computerized tomography (CT) and two-dimensional digital image processing technology were used to study the influence of changing compaction conditions on the mesoscopic structure of asphalt mixture [10; 11], and CT scanning technology was used to establish a three-dimensional mathematical expression of particle morphology [12; 13; 14], which can be seen that mesoscopic analysis can help us to study various properties of the mixture, including the properties of vibration compacted specimens. The purpose of writing this passage lies in the fact that there are two kinds of molding methods of cement stabilized macadam in the Chinese specification. One is the heavy compaction and static pressure molding method, and the other is the vibration molding method. The former is more currently used, but it does not match the site condition well with the improvement of on-site construction methods. Besides, the latter research is not deep enough. Therefore, this study focuses on the vibration compaction method in the specification so as to prove that the vibration compaction method can better reflect the site construction conditions from a mechanic and microscopic perspective, which can facilitate the following study of vibration compaction standard. In this paper, cement stabilized macadam mixed specimens of two kinds of gradation were prepared by the vibration compaction method as well as static pressure molding and heavy compaction method and analyzed from macroscopic and mesoscopic views combined with an on-site sample after a 7 days curing period which came from the Yu-Song test road in Jilin Province, China.