Guidelines for Paving Adjacent Concrete Lanes Seperately

Gatti, Kerri Alyssa (2011) Guidelines for Paving Adjacent Concrete Lanes Seperately. Master's Thesis, University of Pittsburgh.

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Abstract

Often times concrete pavements are constructed by first paving the mainline followed by the shoulder some time later. It is important to factor differences in structure, material properties, and climatic conditions between the mainline and shoulder into the design; otherwise, premature cracking can develop. Cracking can occur in the newly paved lane, the existing lane, or both. The primary objective of this research was to develop guidelines to protect against premature cracking from paving adjacent lanes separately. A review of several case studies revealed that longitudinal shear cracking and transverse cracking in the shoulder are the main distresses associated with delayed shoulder construction. Longitudinal shear cracking occurs due to dissimilar transverse joint openings in the mainline and shoulder. In warm weather, shoulder joints close first causing shear stresses to develop in the mainline. Transverse cracking in the shoulder is caused by thermal incompatibility between the mainline and the shoulder and small shoulder widths (less than 5 ft). The following study uses finite element analysis to analyze the causes of longitudinal shear cracking and transverse cracking in the shoulder. A parametric study was developed for each distress so that guidelines could be established and future occurrences of the distresses can be prevented. Thermal incompatibility between the mainline and the shoulder was the primary factor that caused premature cracking for both distresses. Every effort should be made to prevent the difference of the zero-stress temperatures of the mainline and shoulder from going beyond 20°F.

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