Performance of Concrete Pavements, Volume II: Evaluation of Inservice Concrete Pavements

DTFH61-91-C-00053With the goal of improving future concrete pavement design and construction practices, this project evaluated the performance of 303 inservice concrete pavement sections located throughout North America. An extensive field testing program, consisting of pavement condition surveys, drainage surveys, falling weight deflectometer (FWD) testing, coring/boring operations, and roughness testing, was conducted in order to collect the information needed for analysis. Because many of these pavement sections are part of State-level studies on concrete pavements, a range of design variables (e.g., load transfer, slab thickness, joint spacing, drainage) thought to affect concrete pavement performance are present. Over one-third of the sections was evaluated under a preceding Federal Highway Administration study, meaning that 5-year performance trends are available for some of the sections. Additional pavement performance data are also available for 96 European concrete pavement sections and for 21 Chilean concrete pavement sections. The average age and average cumulative equivalent single axle loads (ESALs) for the North American sections are 16 years and 7.1 million, respectively, compared to 21 years and 21.8 million for the European sections and 9 years and 5.9 million for the Chilean sections. This volume examines the performance of the North American concrete pavement sections included in the study. This examination primarily consists of an evaluation of the effect of concrete pavement design features on concrete pavement performance. Design features investigated include slab thickness, joint spacing, joint orientation, load transfer, joint sealant, base type, drainage, shoulder type, reinforcement, and pavement type. The results of an examination of the backcalculation results are also presented, as are the significant findings of an evaluation conducted on the performance of European and Chilean concrete pavements

Evaluation of Subgrade Resilient Modulus Predictive Model for Use in Mechanistic–Empirical Pavement Design Guide

The characterization of unbound materials in the mechanistic–empirical pavement design guide (MEPDG), also known as the 2002 design guide, is reviewed, and this characterization is applied to Minnesota subgrades. The main emphasis is on the collection of k1-, k2-, and k3-parameters for Minnesota fine-grained soils and the procedure for the interpretation of the resilient modulus test to provide an input to the multilayer elastic theory (MLET) analysis (Level 2 input). This is an important aspect of adaptation of the MEPDG, because the guide recommends measurement of resilient moduli from laboratory testing, but the procedure does not specify how to interpret the test data to obtain an input for an MLET analysis. The resilient modulus test results from 23 samples collected from several Minnesota locations were used to provide information for the nonlinear finite element program and multilayer elastic theory program. The obtained elastic moduli were compared with the MEPDG recommended ranges for subgrade modulus of elasticity based on the soil classification (Level 3 inputs). The MEPDG Level 3 ranges were found to be reasonable

Efeito das variações de temperatura na transferência de cargas em juntas de pavimentos de concreto

Medidas de deflexões com o falling weight deflectometer permitiram a avaliação do comportamento de juntas em pavimentos de concreto simples do ponto de vista de sua eficiência de transferência de cargas (LTE). As investigações mostraram importantes variações nesse parâmetro, quando não há dispositivos de transferência de cargas, entre horários de dias bem como entre estações climáticas distintas (inverno e verão); enquanto que juntas com barras de transferência apresentam, pouca variação nesse parâmetro e encontrando-se em geral entre 90 e 100% de capacidade de transferência, quando há quedas de temperatura, as juntas sem barras chegam a apresentar capacidade de transferência reduzida para 50% no inverno e para 60% no verão. Valores estimados de transferência de carga com um programa de elementos finitos permitiram confirmar a necessidade de tratamento teórico do problema em fases de análise estrutural e projetos de pavimentos de concreto com juntas