Laboratory Study on Cement Slurry Formulation and Its Strength Mechanism for Semi-Flexible Pavement

Abstract

Semi-flexible pavement (SFP) combines the best features of both flexible asphalt and rigid cement concrete pavement. SFP consists of a porous asphalt mixture skeleton with 25 %–35 % voids, filled with selected cement slurry. To better balance the flexible and rigid characteristics between the asphalt mixture skeleton and hardened cement paste in SFP, a further understanding of its cement slurry formulation design is required. Results indicate that the penetrant has a significant effect on the fluidity of cement slurry, improving the flowability of cement slurry. Polycarboxylene-based superplasticizer is a desirable penetrant with the dosage of 1 % by mass of cement. Also, the optimum water–cement ratio of 0.6 for cement slurry is proposed, at which the fresh cement slurry can fully penetrate into asphalt mixture skeleton, and improve the engineering properties of SFP. Additionally, styrene butadiene rubber (SBR) latex is an effective flexible admixture for cement slurry, and its dosage of 2 % by mass of cement is proposed. SBR latex improves the stability of fresh cement slurry and enhances the flexibility of hardened cement paste to reduce the cracks in SFP. At the micro level, the fiber-like hydrated products between SBR latex and cement particles improve the flexibility of hardened cement paste. This reduces the cracks on the interface between asphalt mixture skeleton and hardened cement paste when the ambient temperature changes. It is concluded that chemical admixtures are essential requirements for the production of high performance cement slurry. They allow the fresh cement slurry to fully penetrate the asphalt mixture skeleton with a lower water–cement ratio, improving engineering properties of SFP. The proposed cement slurry formulation can better meet the requirements of mechanical properties and durability characteristics of SFP.

Cementitious Grouts for Semi-Flexible Pavement Surfaces—A Review

“…The workability of grouts can be significantly improved by adding a superplasticizer [ 77 ]. Most commonly, polycarboxylate ether- superplasticizers were used in various studies [ 70 , 78 , 79 , 80 ].…”

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

“…Polymers are the most traditional admixtures used in GSP, including latex, resin, SBS, styrene-butadiene rubber (SBR), and waste rubber [74,84]. Latex and resin are efficient to smooth the high rigidity of HCM and reinforce the tensile strength of the whole structure because of their hydrophilicity, which results in bonding at interfaces between materials [56,76].…”

Study of the Effect of Grouting Material Strength on Semiflexible Pavement Material

“…Cai et al [22], Wang et al [6], Cai et al [23], and other scholars in their studies selected the grouting materials of single strengths, leading to a lack of comparability in the efects of diferent grouting material strengths on the SFP material performance. Te diference between the grouting material strengths chosen by Wang et al [25], Fang et al [28], and Imran Khan and Hartadi Sutanto [29] is not signifcant, and as a result, the improvements in the SFP material performance are not obvious, failing to obtain the substantial change pattern of the grouting material strength's infuence on the performance of SFP materials. Besides, the indicators employed in those studies to assess the infuence of grouting material strength on the performance of SFP materials are not very comprehensive.…”

“…Based on the three-point bending fatigue test, Ren et al [27] explored the efects of two grouting materials with strengths of 12.18 MPa and 35.01 MPa on the fatigue performance of the SFP materials, and the results showed that the fatigue strength of SFP materials increased with the increase in the grouting material strength. Fang et al [28] examined the efect of grouting materials with strengths of 7.7 MPa and 10.2 MPa on the low-temperature crack resistance of SFP materials, and the results showed that the low-temperature crack resistance of SFP materials increased with the increase in the grouting material strength. Imran Khan and Hartadi Sutanto [29] studied the efect of grouting materials with strengths of 9.57 MPa and 12.36 MPa on the compressive strength of SFP materials, and the results showed that the compressive strength of SFP materials increased with the increase in the strength of grouting materials.…”