United States. Federal Highway Administration

FHWA/TX-14/0-6749-1

Tech Report

Texas

Texas. Dept. of Transportation. Research and Technology Implementation Office

Two-lift concrete paving (2LCP) involves placing two layers of concrete (wet-on-wet) instead of a single

homogeneous layer, as is typically done in the United States. 2LCP offers the opportunity to optimize the use of local

aggregates, recycled materials to produce an economical, durable, and sustainable pavement system with the most

desirable surface characteristics (improved skid resistance and reduced noise). Districts including Houston, Fort

Worth, and Dallas have the potential to receive great benefit from the concept by being able to use more local materials

that is not considered appropriate for traditional (single-lift) concrete pavement used. Despite of above mentioned

benefits, challenges of 2LCP are to have the proper paving equipment, pavement construction management, the right

mixture proportions to use the local materials in the bottom lift, which results in an economical pavement placement,

and the proper proportions and materials to ensure adequate surface friction and abrasion resistance in the top lift. A

comprehensive literature review was conducted to gather previous experiences and past performance of 2LCP,

particularly to justify the cost and efficiently execute the process of 2LCP. Surveys and interviews were conducted on

contractors and agencies with experience with 2LCP. A one-day workshop regarding 2LCP was organized to obtain

information from a wide range of agency, construction, equipment manufacturer, and Texas Department of

Transportation (TxDOT) personnel with experience or interests in 2LCP. The workshop also served as a solicitation of

ideas of the best practice, most cost effective approach, concerns, and requirements associated with materials and

construction of 2LCP. Information and inputs collected from literature reviews, surveys, interviews, and the 2LCP

workshop were summarized to provide construction perspectives of implementation of 2LCP, including additional

costs, requirements, and impacts to project scheduling of implementation of this concept. This report discusses

additional requirements in materials, equipment and construction, project scheduling, and jobsite management that will

be beneficial in the implementation of 2LCP construction. This study also evaluated feasibility and cost effectiveness

of 2LCP, particularly in Texas.

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Project 0-6749

US Transportation Collection