A GPR-Based Test Study on the Influencing Factors of the Dielectric Constant of Cement-Stabilized Macadam Bases

Abstract

Dielectric constant is an important parameter for the nondestructive test of cement stabilized macadam base (CSMB) on road by ground-penetrating radar (GPR). However, few studies have been reported on the quantitative relationship between the dielectric constant and the compaction degree, strength indicators, and influencing factors of CSMB. To address the problem, groups of CSMB specimens, which were different in gradation of aggregate (fine or coarse), compaction degree, and curing time, were made and tested for dielectric constant and influencing factors with the help of the Swedish MALA GPR. The relationship between the dielectric constant of CSMB and the influencing factors such as the compaction degree, moisture content, percent residues of aggregate on the sieve of maximum particle size and curing age, and the relationship between the dielectric constant and the unconfined compressive strength were investigated based on several test data and theoretical analysis. The major findings are as follows. There is a good logarithmic correlation between the dielectric constant and the compaction degree of CSMB, and quantitative functions have been established. There is a good linear relationship between the dielectric constant and the unconfined compressive strength of CSMB, and quantitative functions have been established. A comprehensive equation between the dielectric constant of CSMB and the influencing factors such as the compaction degree, moisture content, percent residues of aggregate on the sieve of maximum particle size, and curing age has been established and validated with high significance and small error. The findings are a theoretical basis for the application of GPR to the test and quality assessment of CSMB on roads.

Low Compaction Level Detection of Newly Constructed Asphalt Pavement Based on Regional Index

“…In this paper, three-dimensional ground-penetrating radar is used to detect the dielectric constant by the common mid-point method through different antenna combinations [ 16 ] so that the two-way travel time of the reflected signal at the interface of the structural layer is different, and the electromagnetic propagation equations containing the dielectric constant are established to solve the dielectric constant of the pavement structural layer. As shown in Figure 1 c, a total of nine antenna combinations with the same mid-point but unequal spacing were set during the detection.…”

A nondestructive compaction quality evaluation of runway construction with GPR data

“…In this paper, through compaction experiments on graded crushed stone and cement stabilized macadam, it can be seen that the curves of dry density and moisture content of runway base materials with different mix ratios are shown in Figure 7. Through the analysis of dry density and moisture content of graded crushed stone and cement stabilized macadam with different mixing ratios, the optimal moisture content of the experimental material in this paper is about 3%-6%, and its moisture content has little influence on the propagation and analysis of GPR signal [45,46].…”