Repair of damaged concrete pavements with carbon concreteSubproject V4.12-I: Composite behavior under fatigue loading

Project duration: 2017 - 2019

In Germany, concrete road pavements are usually produced unreinforced with slipform pavers and longitudinal and transverse joints are cut into them as soon as they can be driven over without damage. These dummy joints serve to prevent wild cracking and divide the pavement into individual slabs. To protect against water ingress, salt solutions and dirt particles, the joints are sealed with suitable bituminous sealants, elastic joint profiles or cold grouting (rarely). To avoid pumping effects or hollow layers and thus prevent damage over the service life, the joints require continuous maintenance. [1], [2] Due to the lack of marketable alternatives, concrete pavements usually have to be completely renewed, even if the pavement concrete is only damaged in parts over the slab thickness. This may be the case, for example, if there are numerous cracks, spalling, etc. in the upper zone, if an exposed aggregate texture is to be applied to reduce noise, or if the concrete shows extensive fire damage [3]. It would therefore be expedient to develop a repair method that would allow a new, jointless concrete surface layer to be applied to the old, joint-ridden subgrade concrete. Therefore, a method is to be developed in the present project to investigate the feasibility and functionality of a repair layer made of carbon concrete. Compared to e.g. comparable steel-reinforced pavements [4], this allows relatively low layer thicknesses due to its corrosion resistance. The overall objective of subproject A of the Ruhr University Bochum (RUB) is closely related to the objectives of the joint project. Essentially, subproject A deals with the durability of the composite under fatigue loading. The work in subproject A is intended to demonstrate that a durable bond can be guaranteed between carbon reinforcement and road concrete on the one hand, and above all in the bond joint between old concrete and newly applied carbon concrete, even under cyclic traffic loading. This verification is extremely important against the background of the work in the joint project (with regard to the crack width limitation and the anchorage lengths), since the data on the bond behavior between carbon reinforcement and concrete applied in subproject B of the Technical University of Dresden (TUD) must be permanently valid. The aim of subproject B is therefore to provide characteristic values for carbon concrete and to carry out a crack investigation on carbon concrete specimens subjected to centric tensile loading and to record the measured crack widths and spacing by calculation.