Comparative Evaluation of Crack Width for Reinforced Concrete Bridge Deck

Cracking in reinforced concrete bridge decks is a massively concern in the India. Many concrete bridge decks, inobservant to the age of construction, have shown different levels and patterns of cracking. Not only does cracking of bridge decks weaken the bridge infrastructure, but also allows the inflow of corrosive agents into the reinforcement. In this study, the crack width evaluation of RC bridge deck of span of 5 m. and 9 m. is based on equations given by IRS Concrete Bridge Code 1997 for different cases like- the effect of depth variation, reinforcement diameter, clear cover, variation in live load moment, spacing of tension reinforcement and different no. of tension reinforcement bar to constant width for the same crosssection. This study concluded that crack width increases with increase in clear cover, variation in live load moment and spacing of tension reinforcement while it decreases with increase in reinforcement diameter, depth of the bridge deck and number of reinforced bars and percentage change evaluation of different parameter of 5m and 9m span bridge deck. Keyword: Crack Width, Cracking, Bridge Deck Slab, Crack Spacing.

Study of High-Temperature Properties of Asphalt Mixtures Used for Bridge Pavement with Concrete Deck

The paper presents the issue of resistance to permanent deformations of bridge pavements placed upon concrete bridge decks. In Europe, bridge asphalt pavement usually consists of a wearing course and a protective layer, which are placed over the insulation (waterproofing). Protective layers of bridge pavement are commonly constructed using low air void content asphalt mixes as this provides the suitable tightness of such layers. Due to increased binder content, asphalt mixes for bridge pavement may have reduced resistance to permanent deformations. The article presents test results of resistance to permanent deformations of asphalt mixes for the protective layers. In order to determine the composition of mixtures with low air void content and resistance to permanent deformation, an experimental design was applied using a new concept of asphalt mix composition. Twenty-seven different asphalt mixture compositions were analyzed. The mixtures varied in terms of binder content, sand content and grit ratio. Resistance to permanent deformation was tested using the laboratory uniaxial cyclic compression method (dynamic load creep). On the basis of experimental results and statistical analysis, the functions of asphalt mixture permanent deformation resistance were established. This enabled a determination of suitable mixture compositions for protective layers for concrete bridge decks.