Development of End-Result Specifications for Concrete in Virginia

Abstract

A study described the development of the Virginia Department of Transportation's (VDOT) end-result specifications (ERSs) for hydraulic cement concrete. The work had two phases. In Phase 1, a special provision was developed and applied to two pilot projects. In Phase 2, the special provision was applied to more pilot projects from districts across Virginia. Pay adjustments were not applied for the pilot projects; VDOT's current specifications were applied for acceptance and rejection. The ERSs have three parts. The first part introduces process control measures. The contractor is responsible for the concrete design and is required to provide a quality control plan. The plan addresses all elements that affect quality, including mixture designs, aggregate sources, ingredients, tests and testing frequency, fresh and hardened concrete properties, and control charts. The second part covers the mixture design approval by VDOT. The third part covers project acceptance, which includes pay adjustments depending on test results. The pilot projects are continuing. However, some of the features of the ERS are already included in the supplemental specifications, such as using combined cementitious material and using curing boxes with continuously recording thermometers. Or they are permitted if requested by the contractor and approved by the project engineer, such as using combined aggregates, mixing gravel and crushed stone, combining retarding admixtures and water-reducing admixtures, and exceeding the 300 revolution limit or the time limit of 1.5 h from the addition of water.