Engineering Commons^™

Shear Reinforcement Requirements For High-Strength Concrete Bridge Girders, J. A. Ramirez, Gerardo Aguilar

JTRP Technical Reports

A research program was conducted on the shear strength of high-strength concrete members. The objective was to evaluate the shear behavior and strength of concrete bridge members with compressive strengths in the range of 10 000 to 15 000 psi. The goal was to determine if the current minimum amount of shear reinforcement together with maximum spacing limits in the 2004 AASHTO LRFD Specifications, and the upper limit on the nominal shear strength were applicable to concrete compressive strengths up to 15 000 psi.

A total of twenty I-shaped specimens were tested monotonically to failure. Sixteen specimens were reinforced concrete …

Design Of Durable Concrete Railroad Crossings, Anthony J. Lamanna, Charles F. Scholer

JTRP Technical Reports

Existing precast concrete railroad crossings in the state of Indiana are experiencing too short a life expectancy. This study proposes methods that can be used to produce durable concrete railroad crossings with satisfactory rideability, durability, and longevity. Thirty-two precast concrete railroad crossings were visited in central and northern Indiana. Failures were determined to belong to three major categories: structural capacity causes, environmental causes, and material property causes. A concrete mix was evaluated at three different polyolefin fiber contents and without fibers. Beams were tested in flexure, and modulus of rupture and first crack deflection were recorded for each beam. Cylinders …

Strength And Durability Of Concrete: Effects Of Cement Paste-Aggregate Interfaces, Part I: Theoretical Study On Influence Of Interfacial Transition Zone On Properties Of Concrete Materials, Yiguo Zhang, Wai-Fah Chen

JTRP Technical Reports

This research was based on a two-part basic research investigation studying the effects of cement paste-aggregate interfaces (or interfacial transition zones-HZ) on strength and durability of concrete. Part I dealt with the theoretical study and Part II dealt with the experimental. Part I, the theoretical part, illustrates the effect of ITZ on the concrete properties by assuming its elastic moduli to be varied continuously in the region. A four-phase composite model is employed and three functions are chosen to model the moduli variation in the ITZ. A theoretical solution for an n-layered spherical inclusion model is used to estimate the …

Strength And Durability Of Concrete: Effects Of Cement Paste-Aggregate Interfaces, Part Ii: Significance Of Transition Zones On Physical And Mechanical Properties Of Portland Cement Mortar, Turng-Fang F. Lee, Menashi D. Cohen

JTRP Technical Reports

This research was based on a two-part basic research investigation studying the effects of cement paste-aggregate interfaces (or interfacial transition zones-HZ) on strength and durability of concrete. Part I dealt with the theoretical study and Part II dealt with the experimental. Part I, the theoretical part, illustrates the effect of ITZ on the concrete properties by assuming its elastic moduli to be varied continuously in the region. A four-phase composite model is employed and three functions are chosen to model the moduli variation in the ITZ. A theoretical solution for an n-layered spherical inclusion model is used to estimate the …