THIN STEEL FIBER REINFORCED CONCRETE OVERLAYS AND INLAYS ON OLD PAVEMENTS A TEN-YEAR BELGIAN EXPERIENCE

Abstract

This article documents Belgium's decade-long experience with Thin Steel Fiber Reinforced Concrete (SFRC) overlays and inlays on old pavements. SFRC, a composite known globally for its exceptional technical characteristics, allows for thinner, more efficient use under the same load compared to traditional reinforced concrete, finding its application in various sectors including roadways, industrial flooring, and tollbooth paving. Belgium's foray into thin SFRC overlays between 1982 and 1987 involved the construction of 129,000 m^2 of test sections, leading to decrees and practical implementations based on these evaluations. SFRC's blend of cement, coarse aggregate, sand, water, and steel fibers enhances flexural toughness, crack strength, energy absorption, fatigue resistance, and shear strength. Belgium's application of glued and hooked Dramix fibers has proven effective, with standards set for SFRC's performance evaluation. Test sections from 1982 to 1987 showcased SFRC's potential in overlaying old pavements, leading to varied success. Direct overlays on old concrete showed the critical role of bond strength and the need for an intermediate bituminous layer for successful application. Post-1987 constructions have adapted by reducing slab length and employing bituminous layers to improve outcomes. Evaluations up to ten years post-construction show that sections with intermediate bituminous layers or on partially planed old asphalt pavements performed best. Issues such as corner cracks due to curling were noted, with recommendations including slab breaking, a not too thin bituminous separation layer, and careful preparation to ensure adhesion. For future applications, ensuring clean, milled off surfaces and using bituminous emulsion for better adhesion are suggested for successful thin SFRC overlays or inlays on old pavements. (Abstract generated by AI tool ChatGPT 4)