Search Results (2)

Cement stabilized macadam (CSM) bases are prone to cracking and void damage under long-term traffic loading and environmental actions, which accelerates structural deterioration. Although grouting is an effective method for treating such concealed defects, laboratory-based evaluation of repair effectiveness remains limited. In this study, field-cored CSM specimens were recombined in a cylindrical mold to simulate four void conditions (1/4, 2/4, 3/4, and 4/4), and repaired using an inorganic cementitious composite grouting material based on ultra-fine cement and high-belite sulphoaluminate cement (HBSAC), and modified with ethylene-vinyl acetate (EVA) latex, wollastonite (WO) whiskers, and polyvinyl alcohol (PVA) fibers. The repair effectiveness was evaluated through ultrasonic testing, capacitance measurement, uniaxial compression with acoustic emission (AE) monitoring, and computed tomography (CT). The results show that the longitudinal wave velocity of all repaired groups increases continuously with curing time, with a maximum increase of 21.98% at 28 days. The normalized capacitance response exhibits clear time- and layer-dependent variation, with the 4/4 group showing the most pronounced spatial heterogeneity. In the uniaxial compression tests, the peak load increases from 181 kN in the control group to 201–286 kN in the repaired groups, while the tensile-related AE event proportion increases from 77.35% in the 1/4 group to 89.38% in the 4/4 group. CT analysis shows that the proportion of micropores smaller than 1 mm³ increases from 66.3% to 82.7%, whereas the proportion of pores larger than 100 mm³ decreases from 46.5% to 21.6% after repair. These results demonstrate that the composite grouting material provides effective filling, structural reconstruction, and mechanical enhancement for void-damaged CSM, and that the proposed multi-source characterization framework is suitable for evaluating grouting repair performance. Full article

To further improve the durability of cement-stabilized macadam and guarantee the use quality and sustainability of a semi-rigid base, the current study was carried out. With the help of a dry shrinkage test, temperature shrinkage test, freeze–thaw bending test, and fatigue test, the effect of incorporating PVA fiber on the deformation characteristics of cement-stabilized macadam was analyzed, and the changes in low-temperature residual toughness of the mixture before and after modification were compared. The low-temperature toughness of PVA fiber cement-stabilized macadam was evaluated with the help of the standard toughness evaluation method. The fatigue life prediction equation of PVA fiber cement-stabilized macadam was established based on the Weibull distribution. The results showed that PVA fiber can effectively improve the deformation characteristics, low-temperature toughness, and fatigue performance of cement-stabilized macadam. The low-temperature residual flexural tensile strength and low-temperature bearing capacity were increased by 10.3% and 55.3%, respectively. The residual toughness indices were increased by 58.6%, 88.1%, and 98.3% and the residual strength index was increased by more than 100%. The fatigue life was improved by 178~368% under different stress intensity ratios. The fatigue life values obeyed the two-parameter Weibull distribution, and the correlation between the fatigue life prediction equation and the measured data was significant. The fatigue life prediction error was between 0.03 and 4.9% under different stress intensity ratios. Full article