Potholes are a common pavement distress and a maintenance problem for state and local agencies. This session explores various patching techniques, materials and their performance for asphalt and concrete pavements.
Thermal Influence in the Performance of Static and Dynamic Hot Mix Asphalt Pothole Repairs
Juliana Byzyka, Brunel University LondonShow Abstract
Mujib Rahman, Brunel University
Denis Albert Chamberlain, Brunel University
The advantage of controlled preheating of excavated asphalt surface prior to hot mix asphalt patch repair, referred as “dynamic repair”, is presented in this paper. The heating effects are compared against traditional hot mix repair, referred as “static repair”. Shear bond tests and immersion wheel tracking tests were performed to asses the quality of both types of repair. Pothole excavations were created in the laboratory environment. For static repairs, tack coat was applied at the interfaces of the excavation, prior to laying hot repair material. For dynamic repairs, infrared heat was applied in heating-cooling cycles prior to filling the excavation with hot mix material, without use of tack coat. Heat was applied using an experimental infrared heater set at 6.6 kW with a 230 mm offset from the excavation. The results showed that the shear strength at the bottom and vertical interfaces of dynamic repairs was 78.2% and 68.4% higher respectively than that of static repairs. The immersion wheel tracking test showed that the resistance to water-related damage of dynamic repairs was higher than that of static repairs. It has been concluded that preheating a pothole excavation with infrared heat prior to filling and compaction increases the repair interface bonding strength and durability.
Rapid Inductive Heating of Asphalt Concrete to Hot Mix Temperatures for All-Season Pothole Patching: A Feasibility Study
Ben Cox, U.S. Army Corps of Engineers (USACE)Show Abstract
Webster Floyd, U.S. Army Engineer Research and Development Center
John Rushing, U.S. Army Corps of Engineers (USACE)
Craig Rutland, U.S. Air Force Civil Engineer Center (USAFCEC)
Potholes are a common pavement distress, a nuisance to roadway users, and a maintenance problem for state and local agencies. Patching materials are typically cold mix asphalt (CMA), generic or proprietary, in winter seasons and, ideally, hot mix asphalt (HMA) in warm seasons. While proprietary CMAs generally perform better than generic CMAs, winter repairs with any CMA are usually considered temporary until semi-permanent repairs can be made. However, re-repairing is cost-ineffective to the point the mantra “do it right the first time” has been adopted by some states and researchers. Induction heating has the potential to rapidly heat standard-size containers (e.g. 19 L) of inductive asphalt mixtures to hot mix temperatures (e.g. 150 °C) in a matter of minutes (e.g. 5 minutes), which would allow patching to be conducted with high-quality materials even in winter when conventional HMA is unavailable. The objective of this paper is to investigate the feasibility of this concept. A laboratory investigation evaluated multiple steel aggregates for inclusion in the inductive HMA (iHMA) and designed an iHMA mix that was field-validated by patching simulated potholes. Containers of iHMA were successfully heated in cold weather (-11 to 0 °C) to 160 °C in 5 minutes with 15% steel aggregate by volume, and during full-scale trafficking tests, iHMA patches exhibited comparable rutting characteristics to control HMA patches.
New Polymer Modified Pothole Patching Materials for Timely and Durably Maintenance in Winter-Wet Condition
Mengmei Liu, Chang'an UniversityShow Abstract
Sen Han, Chang'an University
weigong shang, Shaanxi Transportation Construction Maintenance Engineering Co., Ltd.
Mengmei Liu, Chang'an University
shihao dong, Chang'an University
Pavement diseases of cracking, raveling, potholes and water damage often occur in the winter and rainy season, which brings strict requirements to pothole patching materials. In order to solve the two problems of the existing cold asphalt mixtures limiting its application, namely the contradiction between workability or storage and strength, and the problem of low initial strength after installation, new polymer modified patching materials with dense gradation (PADG mixtures) are recommended based on microcapsule technology and reinforcement action. The performance of PADG mixtures was compared with denser graded cold mixtures (DG mixtures) and open graded cold mixtures (OG mixtures) in laboratory, such as workability, storability, stability and durability. Besides, potholes patches using PADG mixtures were investigated over 13 months in field. The test results showed that the PADG mixtures resolved the contradiction between workability or storability and strength of cold mixtures, as well as had better cohesion, stability, freeze-thaw resistance and durability than that of DG mixtures and OG mixtures. Therefore, it can be concluded that PADG mixtures are applicable to timely and durable maintenance in adverse conditions of winter and rain.
Performance of Portland Cement Based Rapid Patching Materials with Different Cement and Accelerators Types and Cement Contents
Shayan Gholami, University of Nebraska, LincolnShow Abstract
Jiong Hu, University of Nebraska, Lincoln
Yong-Rak Kim, University of Nebraska, Lincoln
Due to the requirements of opening pavement to traffic after placing repair concrete, it is essential for that concrete to achieve high early strength. To ensure this, a high cement content is generally used in Portland cement-based rapid-patching materials. Besides its associated high cost, high cement content tends to result in a less stable mix with high drying shrinkage, high autogenous shrinkage, high heat of hydration, and cracking potential. In addition, using chloride-based accelerators has adverse effects on concrete durability. Therefore, this paper presents an experimental assessment to improve rapid-patching concrete mixtures by reducing cement content through optimizing aggregate gradation. A non-chloride-based accelerator was sought to replace the chloride-based accelerator when the accelerators are associated with two different series of patching materials using Type I and III cement, respectively. Fresh, early-age, mechanical, and permeability tests were conducted on each specific mixture design. As an important outcome, patching materials employing lower cement content together with an optimized aggregate gradation can meet the general requirements, which were found from the observation of several key parameters, including early-age strength, setting times, surface resistivity, and heat of hydration. Also, the non-chloride-based accelerator showed promising behavior as an alternative accelerator when it is blended with the proper cement type and content.