A Case Study
The problem...
Interstate Highway 135W in south-central Kansas was originally constructed in 1971 and carries an approximate ADT of 4810. The highway is a dowel jointed PCC pavement consisting of 6" lime-treated subgrade, 4" Portland cement treated base, and 9" of Portland Cement Concrete on the surface, with full-depth bituminous shoulders. The Kansas Department of Transportation knew that sections of I-135W were rough and experiencing driveability problems. The highway was also difficult to maintain; previous rehabilitation efforts consisted of PCCP patching in 1990 and 1994. The highway was cracked, spalled, and rough, but structurally sound. The department was looking for a resurfacing alternative that would be safe, economical, efficient, durable, and give a smoother riding surface.
The solution
The contractor on the I-135W resurfacing project proposed the use of Ralumac micro-surfacing as a means of achieving the department’s objectives. Ralumac micro-surfacing incorporates carefully selected aggregates and bitumen with special polymers and emulsifiers to create stability, even in multi-stone thicknesses. The Ralumac system is applied using specialized techniques and customized machinery. Mixed on site, Ralumac mix is spread directly onto the paved surface. This particular project was unique, in that the Ralumac material was also used in the trenching and patching operations using a specially designed spreader box.
The process
Ralumac micro-surfacing on this project proceeded quickly because the operators, drivers, and support personnel were well-trained. This particular project used two courses for uniform texture and maximum efficiency with total mixture placed less than 50 pounds per square yard. As a rule, two courses produce superior results in terms of durability, surface texture, driveability, and drainage. With application rates as low as 40 pounds per square yard, Ralumac material can fill ruts up to one and one-half inches deep in just one pass. Rehabilitation of concrete sections on I-135 used an additional length skid to aid the leveling and smoothing process.
The results of the I-135W project were particularly encouraging to the Kansas Department of Transportation. Ralumac micro-surfacing means substantial cost savings over traditional resurfacing alternatives. With in-place costs as low as 5 cents per pound, Ralumac micro-surfacing’s benefits stretch over a useful life of 7 years and more. The Ralumac system means minimal material and milling costs up front, and stability, flexibility, and driveability in the long term--even on roads subjected to high temperatures and traffic.
SemMaterials Technology - Solutions for Tough Conditions
This project is just one example of SemMaterials continual exploration of innovative methods for providing safe, fast, durable, and cost-effective pavements to the motorists on our nation’s highways. Contact your local SemMaterials representative for more information on this project, and for help in finding the right solution available in your area for getting the best value from your paving funds and reducing the overall costs of your paving projects.