Cementitious Grouts for Semi-Flexible Pavement Surfaces—A Review

Abstract

The hybrid type of pavement called semi-flexible or grouted macadam has gained popularity over the last few decades in various countries, as it provides significant advantages over both rigid and conventional flexible pavements. The semi-flexible pavement surface consists of an open-graded asphalt mixture with high percentage voids into which flowable cementitious slurry is allowed to penetrate due to gravitational effect. Several researchers have conducted laboratory, as well as field, experiments on evaluating the performance of semi-flexible layers using different compositions of cementitious grouts. The composition of grouts (i.e., water/cement ratio, superplasticizer, polymers, admixtures, and other supplementary materials) has a significant effect on the performance of grouts and semi-flexible mixtures. A comprehensive review of cementitious grouts and their effect on the performance of semi-flexible layers are presented and summarized in this review study. The effect of byproducts and other admixtures/additives on the mechanical properties of grouts are also discussed. Finally, recommendations on the composition of cementitious grouts have been suggested.

Investigating the qualities of grouting material used modifiers in the semi-flexible pavement

“…The additive affected the mechanical properties of cement grout based on the content and speed of grout penetrating full air voids in asphalt concrete. The fluidity of cement mortar is high, which means air voids in the asphalt skeleton were made entirely by cement slurry to decrease the compressive strength of semi-flexible specimens because of the lower strength of cement grout [3]. By contrast, the low fluidity of grout created higher-strength cement mortar cause semi-flexible materials with high strength, but some voids may not fill at the bottom of the specimens [10].…”

“…The mechanical properties of semi-flexible pavement are based on the structure of two materials. Cement grout can increase strength and heat resistance and reduce rutting for semi-flexible material [1][2][3]. The cement grout will penetrate and fill the air voids in the porous asphalt concrete to increase the pavement performance.…”

The Influence of the Application Layer of Pouring Semi-Flexible Pavement Material on Low-Temperature Stress

“…However, its susceptibility to low temperatures renders the cement-based grouting material prone to brittleness, leading to shrinkage deformations and eventual cracking within the weak interface shared by asphalt and the cement-based grouting material [11,12]. Consequently, the low-temperature resilience of PSFM proves inferior to that of other asphalt mixtures [13,14]. In winter, cold regions experience low temperatures and substantial daily temperature fluctuations, contributing to material shrinkage and deformation within pavements.…”

Influence of Sustainable Grout Material on the Moisture Damage of Semi-flexible Pavement

“…The performance of semi-flexible pavement surface materials has shown notable superiority in mitigating rutting with low levels of deformation. As a result of having a greater rigidity modulus, semi-flexible pavements did not undergo any irreversible deformation during the whole of their design life [12]. The geographical location of Iraq affects its climate, making it semi-continental, as it is located within the northern temperate zone with high, almost constant atmospheric pressure.…”