In 1995 US 40 on the west side of Berthoud Pass had several cut and fill slopes that were the result of 1960s erosion control practices. Because the re-seeding and additional fertilization were done using standard materials and methods, no data were available on the performance of the mulches, tackifiers, and germination enhancers. Therefore, this report evaluates only the soil containment products used in three test sections of zone 1 and three test sections of zone 2. The fertilizers, tackifiers, and mulches originally used for this study are not evaluated.

SH-40 west of Berthoud Pass as seen in 1995 was built in the early 1960s. Standard practices for erosion control (in effect during the 1960s) were applied to the cut and fill slopes. The slopes consist of highly erodible and unstable sandy soils mixed with a large quantity of rocks, which vary in size to over two meters in diameter. The snowmelt runoff combined with the severe rain storms of spring and summer wash away the top layer of soil and thereby prevent vegetation establishing itself. Enhancement funds became available for the 1995 construction season to rehabilitate some of the eroded slopes. The purpose of this project is to test various cost effective erosion control materials and installation techniques to provide data for the application on future projects in this and similar areas. Sixteen materials from erosion mats and mulches to different tackifiers are being used within three work zones. The three zones will be evaluated for constructability and overall performance on the better 1 to 1 slopes that are normal for Berthoud Pass.

Introduction -- Department of Transportation research preferences -- Review of published literature and potential research needs -- Summary of identified research gaps and needs -- Master bibliography -- Appendixes.

Corrosion of reinforced concrete structures has been a significant problem for many state and transportation agencies since the application of deicing salts was introduced. Much research has been conducted to develop corrosion protection systems that can prolong the life span of reinforced concrete structures. The Colorado Department of Transportation (CDOT) has several routine and experimental measures to prevent corrosion of the rebar including epoxy-coated rebar, calcium nitrite admixture, organic corrosion inhibitors, a thick cover of quality concrete, and a waterproofing membrane covered by an asphalt overlay. An extensive literature review was performed to collect information on various corrosion protection systems that have been used in the U.S. and around the world. Current CDOT practices in terms of corrosion protection measures were reviewed. A draft inspection plan for Colorado's bridge structures was proposed.

Summary of current research studies.

The purpose of the research conducted was to determine if aggregate degradation takes place and to measure the possible degree of degradation after bituminous mixtures are heated inside the NCAT Asphalt Content Tester. A study was conducted which compared the original aggregate blend (control specimens) to the residual aggregate blend (experimental specimens) obtained after several bituminous mixtures were heated inside the NCAT Asphalt Content Tester. The control specimens and the experimental specimens used to produce the bituminous mixtures were the result of an aggregate sample which was split three times. Two methods of analysis were used to review the gradation results.