Evaluation of applications of DELVO technology
Ragan, Steven A.; Gay, Frank T.
Technical ReportAbstract: 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 into the concrete either at the time of hatching or upon arrival at the work site. In cases where fresh concrete has exceeded the specified delivery times or when more concrete is ordered than can be used at a project, the producer must deal with disposing of it. 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 caused by the generation of excessive tensile stresses resulting from differential cooling within the structure. Tests conducted included adiabatic temperature rise, shrinkage, creep, and modulus of elasticity. An abbreviated investigation was made to assess the feasibility of using DELVO Stabilizer in roller-compacted concrete. Simplification procedures were developed for determining DELVO Stabilizer dosage rates for use in same-day and overnight stabilization of conventional concrete. The feasibility of using DELVO to minimize construction joints in concrete paving and stabilizing shotcrete mixtures was also examined. NOTE: This file is large. Allow your browser several minutes to download the file.
Structures Laboratory (U.S.)Engineer Research and Development Center (U.S.)
Concrete; Concrete admixture; Concrete durability; Concrete mixtures; Concrete additives; Cracking; DELVO; Concrete construction; Concrete testing
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