Evaluation of applications of DELVO technology

Abstract : Fresh concrete is a perishable product that must normally be transported, placed, consolidated, and finished within a relatively short time if the hardened concrete is to develop the desired engineering properties and perform as designed. As a result of these concrete discharge-time limitations, concrete producers often attempt to extend the concrete working time by introducing chemical admixtures. Both waste fresh concrete and mixer wash water are classified as hazardous waste, and the disposal of these materials is highly regulated. The commercially available admixture system DELVO has been developed to enable the concrete producer to tailor the working time of fresh concrete to that needed for particular applications and ambient conditions and to deal with the problems of waste fresh concrete and wash-water disposal. An investigation was conducted to verify the performance test results for concrete containing the DELVO Stabilizer and Activator and to develop new applications for DELVO technology in order to reduce concrete mixture costs, increase concrete construction productivity, and reduce the adverse environmental impact associated with the disposal of waste fresh concrete. The investigation focused attention on an evaluation of DELVO Stabilizer and Activator for standard ready-mixed concrete applications, including long-haul, same-day, and overnight stabilization. Tests were conducted on fresh and hardened concrete and included temperature, slump, air content, time of setting, compressive strength, flexural strength, resistance to rapid freezing and thawing, length change, rapid chloride-ion penetration, and parameters of air-void system. Also investigated was the feasibility of using DELVO Stabilizer to reduce peak temperatures in lean mass concrete and thereby minimize the cracking potential.