Investigation into engineering properties and strength mechanism of grouted macadam composite materials

Abstract

To further understand engineering properties of grouted macadam composite materials (GMCM) used as a surfacing layer in pavement, the mechanical properties and durability characteristics of GMCM were evaluated, and the relevant strength mechanisms were investigated at the micro level. Results indicate that GMCM has better high-temperature stability, fatigue performance and moisture stability than that of conventional asphalt mix, while it shows an acceptable decrease in lowtemperature crack resistance due to the relative brittleness of hardened cement paste. The hardened cement paste also generates a spatial network crystalline lattice in asphalt mix skeleton to form a three-dimensional integral coagulationcrystalloid structure. This facilitates the asphalt mix skeleton and hardened cement paste to bear loads in unison and increase durability of the GMCM. Further, the fibre-like hydrated products of fresh cement slurry on the bitumen film surface increase the interfacial strength between bitumen and hardened cement paste due to toughening and bridging effects, which plays an important role to enhance mechanical properties and durability of GMCM. Finally, GMCM strength is from the internal friction of asphalt mix skeleton, the network structure of hardened cement paste and the adhesion between porous asphalt mix and hardened cement paste. It is concluded that GMCM can better meet the requirements of mechanical properties and durability characteristics than the conventional asphalt mix.

Influential Factors and Evaluation Methods of the Performance of Grouted Semi-Flexible Pavement (GSP)—A Review

“…The propagation of micro-cracks in GSP can be also investigated by SEM (Figure 1). The observation results indicate cracking emerges from the bottoms of samples and expands along with the interface between asphalt and cement [38,40]. This reveals that the asphalt-cement interface is the weak interface existing through the whole depth of GSP structure, approved by the Heavy Vehicle Simulator test and the Dynamic Cone Penetrometer test [41,42].…”

“…This is because the excess stiffness of GSP limits the deformation of whole structure. However, admixtures can be efficient to accomplish a significant enhancement in tensile strength of GSP [38]. That is, the modified GSP shows improved low -temperature performance in the SCB test, creep test, and ITS test at −10 • C [108].…”

“…The freeze-thaw test is divided into the freeze-thaw splitting test (ST) and freeze-thaw indirect tensile strength (ITS) test. Thus, the results of retained Marshall stability (RMS) and tensile strength ratios (TSR) are summarized and illustrated in Figure 3 [6,38,49,70,77,103,104,110,111]. Moisture resistance of GSP is significantly enhanced with high void rate OMA.…”

Cementitious Grouts Containing Irradiated Waste Polyethylene Terephthalate

“…On the other hand, rigid pavements are constructed from cement concrete with or without reinforcement. Rigid pavements have better durability, high compressive strength but have some disadvantages such as; provision of joints, rough-riding quality, slow setting time, high susceptibility to thermal stresses, high initial cost and maintenance efforts, cannot simply be ignored [6][7][8]. Taking into consideration the disadvantages of both flexible and rigid pavements there was a need for an alternative pavement design that can combine the positive attributes of conventional flexible and rigid pavements with a view of the improvement in serviceability and performance.…”

Development and application of new composite grouting material for sealing groundwater inflow and reinforcing wall rock in deep mine

“…Currently, the research for grouting materials mainly includes the strength mechanism 2 , 3 , the workability 4 – 6 , and the admixture 7 , 8 . Based on the working performance of ordinary grouting material, some special grouting materials were put forward according to different geological conditions.…”