Flexible composite carpet covering system for road joints

Abstract

A road surface system consisting of a 30 mm thick, specially developed composite surface layer made of a high flexural strength mortar with fine sand from granite quarry waste and distributed reinforcing fibers, a binder-adhesive interface for bonding the layer to a rigid concrete substrate and joint bridging details aligned over expansion joints, the system providing a continuous driving surface over expansion joints while compensating for movements of the underlying slab.

Description

AREA OF INVENTION

[0001] The invention relates to devices for the surface treatment of road surfaces, which integrate a specially developed composite top layer with high flexural strength, a binder-adhesive interface and joint bridging details to create a continuous, low-jerk road surface over expansion joints in rigid roadways. BACKGROUND OF THE INVENTION

[0002] Rigid concrete pavements have expansion joints to accommodate temperature fluctuations and shrinkage. However, exposed joints lead to unevenness in the pavement surface, causing shocks, impact noise, and localized damage under repeated traffic loads. Conventional joint sealing and edge repairs preserve movement but leave steps in the pavement profile, which can impair comfort and lead to spalling or chipping. Thin asphalt surface courses can smooth the profile but are prone to reflection cracking and rutting at the joints, while thicker surface courses increase costs and can impede joint movement. A thin, high-flexural, fiber-reinforced composite layer that bridges joints while accommodating minor movement can provide a seamless, low-noise pavement surface without restricting the necessary expansion of the pavement slab.It combines the durability of rigid road surfaces with a flexible, specially developed surface layer. SUMMARY OF THE INVENTION

[0003] The invention relates to a flexible composite carpet covering system, consisting of: an approximately 30 mm thick layer of engineered composite carpet (ECC) made from a high-flexural-strength mortar with fine sand from granite quarry waste and distributed reinforcing fibers; a binder bonding layer that ensures a permanent bond with concrete slabs; and a joint bridging layer that allows movement of the underlying joints while maintaining a continuous road surface. The ECC is laid continuously over rigid road slabs, including expansion joints, thereby preventing perceptible surface interruptions and the associated impact noise. At the same time, the tensile strength of the composite material and the fiber bridging layer prevent reflective cracking and distribute stresses.Preferred embodiments include a surface-treated concrete substrate for improved adhesion, a moisture-tolerant binder compatible with cementitious coatings, and fiber types and dosages selected to achieve the desired ductility and flexural strength at a low layer thickness. This ensures a long service life and smooth driving comfort. DETAILED DESCRIPTION

[0004] The surface course system consists of an approximately 30 mm thick layer of engineered composite material (ECC). This is produced from a high-performance mortar mix containing fine sand from granite quarry waste, suitable for dense packing, as well as a cementitious binder with optionally additional cementitious materials and dispersed reinforcing fibers (e.g., PVA, PE, or steel microfibers). The fiber dosage is precisely calibrated to achieve high flexural strength and tensile elongation. The fresh ECC mix exhibits good workability for installation in thin layers, self-compacting properties, and fiber dispersion to prevent lump formation. Setting and curing times are compatible with phased traffic opening. Before the ECC is installed, a binder bonding layer is applied to the prepared concrete slab surface.Epoxy polymer-modified cement or epoxy resin systems can be used as bonding agents, ensuring high adhesion, moisture resistance, and compatibility with cementitious surface layers, and preventing delamination under traffic loads. Substrate preparation includes milling or shot blasting to remove contaminants, create mechanical interlocking, and profile matching. Substrate defects near joints are repaired and leveled to ensure a uniform ECC layer thickness. Joint bridging preserves the expansion capacity of the underlying slab: the ECC is laid continuously over the joint to create a seamless surface.At the joint line, a controlled micro-relief or decoupling strip of minimal width and depth can be incorporated within the ECC layer to adjust the stress distribution and avoid stress concentrations while maintaining surface continuity. Alternatively, a compliant intermediate layer of thin, flexible membrane, aligned over the joint, can be embedded at a medium depth within the ECC to accommodate minimal movement without translucency. In both cases, the surface remains flat, thus preserving ride comfort. Fiber selection and dosage are targeted at ductile bending behavior and crack width control under thermal and traffic-related loading.Typical flexural strength values ​​exceed those of conventional mortars at comparable layer thicknesses, and the crack toughness after crack formation ensures narrow crack widths that resist the penetration of water and road salt. The fine sand, obtained from granite waste, is processed (washed, sieved) to ensure a uniform particle size distribution and a low proportion of harmful particles. Its angular shape improves the mortar's strength and adhesion. Installation is achieved by screeding and smoothing, suitable for thin coatings. Curing is carried out using membranes or wet curing to achieve the desired properties and dimensionally stable curing. The system edges and connections to adjacent components (drainage systems, manholes) are provided with chamfered transitions to prevent step formation.The surface structure is grooved or brushed to meet slip resistance requirements without compromising the thin-wall's stability. Load-bearing capacity is ensured by the composite material's ability to bridge micro-movements at the joints with minimal stress concentration, thus reducing reflection cracking. In the event of microcracking, the fiber bridging limits the crack opening to submillimeter widths, maintaining surface continuity and durability. Maintenance includes regular cleaning and inspection. Localized defects can be milled out and repaired with compatible ECC compounds due to the thinness of the material. The system can be prefabricated in panels and bonded on-site or cast on-site; in both cases, the bonded interface and joint bridging details are retained as described to ensure movement and ride comfort.

Claims

[1] A road surface system comprising a 30 mm thick specially developed composite surface layer made of a high flexural strength mortar with fine sand from granite quarry waste and distributed reinforcing fibers, a binder-adhesive interface for bonding the layer to a rigid concrete substrate and joint bridging details aligned over expansion joints, wherein the system provides a continuous driving surface over expansion joints while compensating for movements of the underlying slab. [2] System according to claim 1, wherein the reinforcing fibers and the mortar composition are selected to provide a tensile strain capacity and post-cracking toughness that limits reflection cracking and maintains surface continuity under thermal and traffic loads. [3] System according to claim 1 or 2, wherein the joint bridging details comprise a flexible intermediate layer or a controlled release device within the composite thickness at the joint line, which adjusts the stress distribution while maintaining a flat surface profile for a smooth transition. [4] System according to any of the preceding claims, wherein the binder-adhesive interface consists of a moisture-tolerant epoxy or polymer-modified cementitious adhesive applied to a mechanically prepared concrete surface to achieve high bond strength and to resist delamination under repeated wheel load.