State-of-the-Art of Grouting in Semi-flexible Pavement: Materials and Design

Semi-flexible Pavement (SFP) is a composite pavement that consists of an open-graded friction course (OGFC) or porous asphalt mixture (PAM) having an air void content of 20–35%, grouted with cement paste/mortar with a fluidity of 10–16 s. The OGFC or PAM provides flexibility, skid resistance, and the grouting provides rigidity, capacity to carry heavy traffic without rutting, together to achieve a joint-free, rut-resistant pavement. The interconnected voids in the asphalt mixture filled with grout will be the secondary skeleton and help in load transfer, being the stone-on-stone contact with the primary skeleton. The review of supplementary cementitious materials (SCM), the formulation of the materials to meet the grouting design requirements, and the parameters to measure the efficiency are necessary to provide a more durable and fatigue-resistant pavement. The first part of the study discusses the mechanical properties of the materials, the design and preparation of the grouting. The grouting parameters and the contribution of grouting to SFP’s performance are discussed in the later part. The review indicated that the marginal aggregates can also be used, and with the use of SCM, durability, and strength can be increased. Concerning the benefits of grouting in SFP, scope exists for further research to design and understand the grouting better, which helps SFP perform better.