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ABSTRACT Semi flexible pavement (SFP) has drawn great attention in recent years due to its high load bearing capacity. Its strength, rutting resistance, and component constitution have been investigated comprehensively [...]

ABSTRACT Semi-flexible pavement (SFP) has been promoted to apply in pavement engineering mainly for its excellent performance in rutting resistance. Since the reinforcing mechanism of its stiffness and strength is [...]

ABSTRACTThis paper aims at investigating the microstructure and early-stage (Keywords:Asphalt emulsionCold recycledEarly-stageStrengthMicrostructure1. IntroductionCold recycling of asphalt pavement is an effective way to reduce construction materials and cost as well as [...]

ABSTRACTThe inhibition performance of a water-soluble silane on reinforcing steel in saturated Ca[(OH).sub.2] solution contaminated by [Cl.sup.-] was investigated and compared with commonly organic inhibitor N,N-dimethylethanolamine (DMEA) using electrochemical techniques [...]

ABSTRACT Plenty work has been done on asphalt's moisture susceptibility at macro scales. However, limited work was done at micro scale to aid in the understanding of interactions between asphalt [...]

ABSTRACT Concrete is an inherently multi-scale hydrophilic composite. Superhydrophobic surfaces have not been created solely by using chemical modification to reduce surface energy. A superhydrophobic concrete surface was fabricated by [...]

ABSTRACT A recent microstructural model for simulating external sulfate attack on cement paste is used to calculate the driving force for local expansive growth of AFt phase in terms of [...]

ABSTRACT Cement-asphalt (CA) mortar, a grouting material consisting of Portland cement (PC), asphalt emulsion, sand, water and other related admixtures, has been widely used as a cushion layer material in [...]

ABSTRACT The objective of this paper is to investigate and determine the critical physical and chemical parameters corresponded with long-term aging of asphalt binder in both laboratory and field. Firstly, [...]

ABSTRACT Based on the discrete element method (DEM), this study conducted the virtual simulation of wheel tracking tests to predict the rutting deformation of asphalt mixtures and analyzed the micromechanical [...]

ABSTRACT This paper aims at investigating the development mechanism of early-stage strength for cold recycled asphalt mixture using emulsion asphalt. The influence parameters of early-stage strength development for cold recycled [...]

ABSTRACT Cement-asphalt mortar (CA mortar) is an inorganic-organic composite, which combines both advantages of the mechanical property of cement and flexibility of asphalt. Therefore, it has been widely applied in [...]

ABSTRACT The objective of this paper is to investigate the effectiveness of Rejuvenator Seal Materials (RSM) on the behavior of Hot Asphalt Mixtures (HMA). Firstly, temperature sweep test was conducted [...]

Cement grouted asphalt mixture (CGAM) is developed with both flexible and rigid materials. It can be used to enhance the anti-rutting performance and increase the load bearing capacity of the pavement. However, the influences of cementitious grouting materials and asphalt binders on CGAM’s failure behavior have not been fully understood yet. In this study, the indirect tension (IDT) test, the compression test and the semi-circular bending (SCB) test were conducted to evaluate the strength and cracking resistances of CGAM with different cementitious grouting materials and asphalt binders. With different binders and bitumen/aggregate ratios, two kinds of cementitious grouting materials and six asphalt mixture skeletons were used in mixture design. IDT test results showed that the indirect tensile strength of CGAM would decrease as the bitumen/aggregate ratio increases. The addition of additives would also lower CGAM’s IDT strength. CGAM samples with high-strength cementitious grouting materials exhibited a higher strength than those with early strength cementitious grouting materials. However, there were not any distinct differences in the CGAM’s compression strength when different cementitious grouting materials and asphalt binders were used. SCB results showed that increasing the asphalt binder content and using additives can enhance the cracking resistance of CGAM. CGAM with high-strength cementitious grouting materials would crack more rapidly due to its rigidity. In the end, a two-way ANOVA was conducted on the results of the three tests. It is found that the type of grouting materials impacts the failure behavior of CGAM more significantly than the influences of the asphalt binder content. The addition of additives would also affect the failure of different CGAM samples. The findings in this paper can provide guidance for designing CGAM with better pavement performance.

Printability is a crucial attribute for 3D-printed cement-based materials, as it not only governs the material's printability but also directly impacts the quality of the final structure. A good printability indicates that the printed materials are flowable for transport and extrusion, followed by a rapid increase in strength to establish a stable structure. In this paper, a novel strategy is proposed to enhance the 3D printability of cementitious materials by leveraging the rapid strength enhancement of fresh mortar during in-situ polymerization of acrylamide (AM) in the matrix within 30–60 min of contact with water. Prior to extrusion, AM monomers are absorbed onto cement particles to enhance the flowability of mortar to approximately 185 mm, thereby improving pumpability and extrudability of printed materials. Shortly after extrusion, in-situ polymerization of AM monomers within the mortar takes place, resulting in a sudden albeit modest strength increases in the fresh mortar, enhancing the buildability of the printed mortar. Moreover, the flexural strength of 3D printed filaments with 5 % AM are increased by 52.4 % at 28d, respectively. Meanwhile, the interactions between the AM in-situ polymerization and cement hydration are comprehensively discussed. This innovative approach to enhance 3D printability is expected to drive the advancement of 3D-printed materials with enhanced adaptability and superior properties.

Semi-flexible pavement (SFP) is made of a composite material that consists of porous asphalt concrete (PA) filled with highly flowable grouting material. At present, most researches on SFP focuses on the materials design and pavement performance characterisation, and very limit effort has been made on evaluating its freeze–thaw durability, which limits the application of SFP in cold regions. The present paper was to fill this gap. In the study, two SFP mixes made with a given PA but two different grouting materials (early-strength (ES) and high-strength (HS) grouting materials) were evaluated. ASTM C666 freeze–thaw durability tests were performed not only on the SFP mixes but also on each of SFP component (PA, ES and HS grouting materials), where relative dynamic modulus and mass loss of the tested samples were measured. In addition, indirect tensile strength of the samples was also tested, and the stiffness and strain–stress behaviour of the samples were evaluated. The results indicate that the order of the freeze–thaw resistance of the individual components was the PA matrix < ES grouting material (4.9 MPa at 3 h and 25.4 MPa at 28 days) ≪ HS grouting material (82.4 MPa at 28 days). The relative dynamic elastic modulus and strain–stress behaviours of SFP-ES samples were very similarly to those of PA, indicating the loss of integrity of the composite during freeze–thaw cycling. Differently, relative dynamic elastic modulus and strain–stress behaviours of SFP-HS samples were close to those of HS grouting material, indicating that enhanced freeze–thaw resistance of a SFP mix can be achieved by incorporating a high strength grouting material into a PA matrix.

Cement asphalt mortar (CAM) could be considered as the cement mortar modified by asphalt emulsion, which would alter the microstructure of cement mortar and thus exert significant influence on the mechanical properties and durability of CAM. In the current research, the effect of cationic asphalt emulsion on the compressive/flexural strength, flexibility, water adsorption, permeability and sulfate attack of CAM were investigated. The obtained results indicated that, both the compressive strength and flexural strength of CAM all decreased obviously with the increase of A/C (mass ratio of asphalt to cement), on the contrast, the incorporation of cationic asphalt emulsion would improve the flexibility of CAM. The increased A/C would suppress the water transportation, including water adsorption and penetration, into CAM, which is mainly due to the reduction in the pore connectivity and the hydrophobization on the wall of pores, thereby beneficial to improve the durability of CAM. The transportation pathway of water containing sulfate ions into CAM would be inhibited with the increase of A/C, which suppressed the formation of erosion products and in turn decreased the damage of the microstructure of CAM, that is, the incorporated cationic asphalt emulsion would enhance the sulfate attack resistance of CAM. The field emission scanning electronic microscopy (FESEM) observation showed that, with the increase of A/C, more and more asphalt film formed in the CAM, while less and less cement hydration products were generated, which is correlated well with the variation of mechanical properties, water sorptivity and sulfate attack resistance of CAM.