Working visit to the USA
During his working visit to the USA, Artem Bezuglyi, Director of "DerzhdorNDI" SE continued a series of meetings with representatives of state authorities and scientific community of individual states, in particular, he met with the leadership of the Iowa Department of Roads and the National Technology Center for Cement Concrete Pavements of the University of Iowa. The most interesting among the organizational and technological aspects of road construction in Iowa is the following:
85 percent of the total length of roads in the state are cement concrete roads. This is due to the state's agricultural orientation and the presence of a large number of heavy trucks. The high strength of cement concrete roads allows for the passage of heavy vehicles at any time of the year and provides increased resistance to rutting.
Designers expect the life cycle of cement concrete roads to be 40 years (while asphalt concrete roads are 12-13 years).
The determining criterion in making design solutions for the pavement option is localization (the need to use local materials) and economic feasibility during the life cycle.
In Iowa, only JPCP is used - a technology for constructing a monolithic cement concrete pavement with a pinned plate connection, although in other US states there are successful examples of the use of technologies for the construction of cement concrete pavement with joints and plate reinforcement (JRCP) and continuously reinforced cement concrete pavement (CRCP).
Cement concrete road pavements in the United States are arranged in a single layer, unlike the German system (which provides for a two-layer pavement).
Recently, the WHITETOPPING technology has been widely developed, which involves applying a layer of the cement-concrete mixture to the existing asphalt pavement. This allows prolonging the service life of the road surface by 10-30 years by strengthening the road surface (the existing road surface remains as a base for the cement concrete pavement). For example, our team has already developed R V.2.3-37641918-918:2021 "Recommendations for reinforcement of asphalt pavement with cement concrete layers".
Salt solutions are used as de-icing materials on roads with cement concrete pavement.
The contractor can receive up to 3 percent of the contract value as bonus payments if it achieves high-quality standards (i.e., actual quality indicators exceed the standard). However, in case of a slight deviation from the quality indicators, the contractor is subject to penalty payments, and the amount of payment is reduced.
The contractor does not provide a warranty for the road. After the road is put into operation, no questions are raised against the contractor. In other words, a system has been built whereby the customer and the contractor effectively exercise quality control at the stage of work performance.
A lot of interesting information about new materials and technologies is available on the website cptechcenter.org.
Thus, the best American practices in road construction should be used to improve the regulatory framework
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