Recycled Asphalt Pavements - Kossuth County Iowa, HR-176, 1975

Kossuth County is located in North Central Iowa bordering on the State of Minnesota. It is the largest county in Iowa consisting of 28 congressional townships. The population of the county is 23,000 of which 11,000 people live in the rural area. There are 13 towns located in the county with the county seat, Algona, being the largest with a population of 6,100. Major industry of the area is grain farming with some beef and hog production. Naturally, where there is good grain farm land it follows that there is poor soil available for road construction and pavements. However, below the 3 to 4 feet of good farm land of Kossuth there is present a good grade of clay soil which does make an adequate base for surfacing when placed and compacted on top of the roadbed. As early as 1950, the then Kossuth County Engineer, H.M. Smith, embarked on a program of stage construction in building new grades and pavements. The goal of his program was primarily to conserve the county's rapidly dwindling supply of surfacing materials, and also, to realize the side effects of providing smooth and dustless roads for the public. Engineer Smith was fully aware of the poor soils that existed for road construction, but he also knew about the good clay that lay below the farm soil. Consequently, in his grading program he insisted that road ditches be dug deep enough to allow the good clay soil to be compacted on top of the roadbed. The presence of the compacted clay on top of the road resulted in a briding affect over the farm soil. The stage construction program satisfied the objectives of aggregate construction and dust control but did generate other problems which we are now trying to solve as economically as possible.

Special Report on Alkali-Aggregate Reactivity in Iowa, MLR-80-03, 1980

The purpose of this investigation was to obtain information relative to the alkali-silica reaction in Iowa aggregates. Of particular concern were those aggregates in southwestern Iowa thought to be potentially alkali reactive. Further, should those aggregates have proven to be alkali-reactive, at what cement alkali content could these aggregates be considered to be deleteriously reactive? If the aggregates were proven to be reactive, what types of effects might show up in a structure in which an alkali-silica reaction has occurred? Also, what environmental conditions would cause the reaction? Finally, based on the information obtained from the investigation, would it be possible to raise the cement alkali content specifications? Would the Iowa DOT eliminate the alkali content limits altogether except for cement used with reactive aggregate in the same manner as AASHTO or ASTM? Also, would there be any other side effects that might occur as the result of using high alkali-cement?

Evaluation of Deicing Materials and Corrosion Reducing Treatments for Deicing Salts, TR-471, 2007

Effective winter maintenance makes use of freezing-point-depressant chemicals (also known as ice-control products) to prevent the formation of the bond between snow and ice and the highway pavement. In performing such winter maintenance, the selection of appropriate ice-control products for the bond prevention task involves consideration of a number of factors, as indicated in Nixon and Williams (2001). The factors are in essence performance measurements of the ice-control products, and as such can be easily incorporated into a specification document to allow for selection of the best ice-control products for a given agency to use in its winter maintenance activities. Once performance measures for de-icing or anti-icing chemicals have been specified, this allows the creation of a quality control program for the acceptance of those chemicals. This study presents a series of performance measurement tests for ice-control products, and discusses the role that they can play in such a quality control program. Some tests are simple and rapid enough that they can be performed on every load of icecontrol products received, while for others, a sampling technique must be used. An appropriate sampling technique is presented. Further, each test is categorized as to whether it should be applied to every load of ice-control products or on a sampling basis. The study includes a detailed literature review that considers the performance of ice-control products in three areas: temperature related performance, product consistency, and negative side effects. The negative side effects are further broken down into three areas, namely operational side effects (such as chemical slipperiness), environmental side effects, and infrastructural side effects (such as corrosion of vehicles and damage to concrete). The review indicated that in the area of side effects the field performance of ice-control products is currently so difficult to model in the laboratory that no particular specification tests can be recommended at this time. A study of the impact of ice-control products on concrete was performed by Professor Wang of Iowa State University as a sub-contract to this study, and has been presented to the Iowa Highway Research Board prior to this report.