We Keep Putting Stuff in Asphalt Concrete

There are two parts to the “holy grail” of asphalt concrete pavement performance: slow pavement cracking and reduce rutting caused by high truck traffic volumes. To this end, after modifying the aggregate blend, state highway departments and research universities seek additives to the simple mixtures of asphalt cement and well-graded […]

Pavement Performance: What is Going on Here?

From a cursory glance of the photograph, you could think mud had dropped from a pickup truck.  An experienced engineer see that the light-colored markings are mineral fines (the powdery portion of crushed rock) being leeched out of the pavement structure by subsurface water pressure. The source could be, excess […]

Basic Concepts: Drainage

The typical pavement is a roadway – a long, relatively narrow strip of pavement which drains to structures along the curbs or out towards ditches. Water is not likely to remain on the pavement surface for long periods. Even water that gets into the pavement layer through cracks will flow […]

Basic Concepts: Heavy Vehicles

The typical parking lot is designed to carry light loads – passenger vehicles. There will be delivery trucks, garbage trucks, and maybe, buses. If your pavement has failures with cars passing over it, there are serious problems. Trucks and buses are a different matter.  There was a rule of thumb […]

Basic Concepts: General Problems of Large Paved Areas

We design and try to build a uniform pavement structure (see above) to cover a site that is not homogeneous.   Our most recent example of land resisting being covered happened after several days of heavy rainfall in south Texas. The photograph presents a five-year-old pavement which appears to have […]

Basic Concepts: Pavement Ownership Costs Money

The greatest cost in the pavement lifecycle is the initial construction cost followed by future overlay or reconstruction costs. The surface type selection will determine the number of pavement layers and their thicknesses and the ultimate costs. In general, hot mix asphalt concrete will have lower initial costs in most […]

Basic Concepts: Pavement Performance Primer

Pavements keep us out of the mud Pavements keep us out of the mud This was mentioned in our first posts. There are a multitude of options to keep us clean and dry. What is the budget? What is the surface type, how many layers, and how thick are the […]

Frost Heave: Seriously, Fix the Problem

Frost heave is cause by a deep freeze of poorly drained, fine soils. The free moisture in the soil expands when frozen. The freezing draws more moisture up and into the frozen layer to create an ice lens. When the ice expands, the sidewalk is pushed up. The photograph shows […]