Optimized Spacing Of The Longitudinal Reinforcement In CRCP To Avoid Horizontal Cracking

Continuously reinforced concrete pavement (CRCP) is characterized by the absence of transverse contraction joints and the presence of longitudinal and transverse reinforcement. The continuous longitudinal reinforcement holds the transverse cracks, caused by the longitudinal shrinkage of concrete, tightly together and thus provides long term performance with minimal maintenance cost. Field investigations on recently constructed CRCP's in Flanders region of Belgium indicated horizontal cracking in the vicinity of the longitudinal reinforcement under the transverse cracks which eventually causes the punch-out distress at the edge of the pavement slab. This paper shows the results of a finite element (FE) study to investigate the effect of varying longitudinal reinforcement on the risk of horizontal cracking in CRCP under typical Flanders conditions. For this purpose, a (3D) FE model of CRCP is developed using a FE package Diana 10.2. The varying longitudinal reinforcement with a most narrow spacing of 125mm in the outer region of the pavement slab is applied while keeping the same CRCP reinforcement ratio. A comparison is made with the conventional longitudinal reinforcement spacing (170mm). Development of concrete stress in the vicinity of the longitudinal reinforcement is plotted against the different longitudinal steel spacing. Findings show that the stress in concrete near longitudinal reinforcement is significantly reduced up to maximum 17% when the narrow spacing is used. In addition, the steel stress in the longitudinal reinforcing is reduced up to maximum 31.75% in the outer region of the pavement slab.

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End-Result Specifications for Warranted Asphalt Pavements

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/1632-01 ◽

1998 ◽

Vol 1632 (1) ◽

pp. 1-12 ◽

Cited By ~ 2

Author(s):

Sameh Zaghloul ◽

Nasser A. Saeed ◽

Ali Al Jassim ◽

Ahmed M. Rafi

Keyword(s):

Functional Performance ◽

Power Spectral Analysis ◽

Maintenance Cost ◽

Long Term Effects ◽

Pavement Roughness ◽

Power Spectral ◽

Long Term Performance ◽

User Friendly ◽

Term Performance

Long-term pavement performance is highly dependent on its initial condition. High initial roughness leads to higher maintenance and rehabilitation costs, to shorter service life, and to significant reduction in riding quality. A performance-based specification applicable for new and rehabilitated warranted pavements is developed and presented here. The primary purpose of this specification is control of the initial longitudinal roughness of pavements, which will lead to smoother pavements and hence satisfactory long-term performance. In this specification, pavement roughness is measured by using Class I or calibrated Class II profilometers, such as infrared and laser profilometers. Tests are performed on each asphalt layer before the next layer is constructed. Three criteria are considered in the specification: surface tolerance, roughness indices, and repeated waves. It should be noted that this specification focuses on the functional performance of pavements and does not directly address their structural performances. A user-friendly software is developed to implement this specification. The software is capable of simulating straightedge inspections, calculating roughness statistics, and performing frequency analyses, such as power spectral analysis. With the software, a pavement section can be evaluated, tested, and analyzed in few minutes. Highway agencies as well as contractors will benefit from implementing this specification. Highway agencies will benefit by being able to achieve the goal of having safe, smooth, and economic pavements, and contractors will benefit by reducing maintenance cost during maintenance and warranty periods. Also, contractors will get quick results and meaningful feedback to the paving operation. A payment structure, including bonus payments for extended service lives, is included in the specification. This payment structure is based on the long-term effects of the initial roughness on the pavement life-cycle costs. The bonus program will encourage contractors to achieve higher levels of quality.

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