The purpose of this report is to give an overview of the number of Minnesota agencies that use Infrastructure or Pavement Management software and provide information as to their common components and requirements. Software of this type is used to store and analyze the various components of an agency's infrastructure. This might include such things as streets, highways, bridges, signs, utilities, etc. Most
systems of this type are capable of data storage, retrieval, analysis and forecasting or projecting future conditions and need for maintenance.
A Federal Highway Administration policy, issued January 13, 1989, requires all states to have a fully operational Pavement Management System (PMS) within four years of the issuance of the policy. As more and more states implement a PMS, the number of county and city agencies will also likely increase. This report reviews the current status of Minnesota cities and counties in terms of their implementation and use of software of this type.
Erosion control encompasses a large area that includes permanent and temporary systems. Permanent systems can include soil stabilization, riprap and hard armor systems, and scour protection. Temporary systems include soil stabilization with geotextiles, chemical treatment, hay bales, and silt fences. This paper will deal with both permanent and temporary systems, but only as they relate to soil stabilization on slopes.
Reflective cracking is the cracking or fracturing of a bituminous or PCC concrete overlay that results from movement of the older underlying pavement layers. The underlying cracks reflect through, usually within one to two years creating the same patterns of cracking in the overlay. Eventually reflective cracks deteriorate into
raveling and spalls over old asphalt pavements, and become close parallel cracks creating bumps over the joints in rigid pavements. Reflected cracks allow moisture to migrate into the base or subbase. This can cause loss of bond between the old surface and the overlay, result in pumping, and also cause loss of support of the
subgrade. The early deterioration of the overlay causes an increase in maintenance costs for crack sealing and patching
Geotextiles have been widely accepted as a separation layer in pavement structures. Strength of a pavement requires that the coarser layers not be infiltrated by finer subgrade materials. However in practice, this is not always achievable. For silty type soils, when saturated conditions occur with repeated loads, high pore
pressures develop in the subgrade causing the material to become unstable. Fines are then forced into the voids of the aggregate base over time lowering the shear strength of the base course and decreasing the drainage capacity. With pumping, the result is a reduction in the effective thickness of the road system. This can occur rapidly over very soft soils, and over time creating the need for early maintenance. The geosynthetic is designed to act as a separation interlayer to prevent aggregate from penetrating the subgrade under action of applied loads. It can also prevent the intrusion of the subgrade soils into the base layer.
