November 13th Dinner Meeting

November 13, 2019
5:15 PM - 8:15 PM

Erie Cafe
536 W. Erie Street
Chicago, IL 60654
Venue website

Title: Extended Workability for Concrete: Goals and Challenges


Presenters: Jose Pacheco Ph.D., Jan Vosahlik Ph.D.


CTLGroup, Concrete & Cement-Based Materials Group

Modern construction often requires that concrete mixtures for special applications are designed with extended workability. Common industry practice to evaluate extended workability consists of measurements of a concrete slump or slump flow at time intervals. Performance requirements for initial, interval, and final slump and slump flow are defined at the discretion of the specifier but vary greatly from project to project. Along the slump or slump flow evaluation, determination of other fresh properties and hardened properties are often required as part of the extended workability performance testing. In some cases, however, challenges related to the extended workability performance can lead to constructability issues such as plastic shrinkage cracking. This presentation will cover the current standard of practice for extended workability evaluations, strategies to achieve workability extension without detrimental effects to the hardened concrete performance, and present case studies in which the intended evaluation resulted in very different field performance.


Jan Vosahlik

Dr. Vosahlik specializes in the development, characterization, and evaluation of concrete mixtures, with focus on conventional, self-consolidating, high-performance, and other specialty concretes. He is an expert in rheology of cement-based materials, fresh concrete properties optimization and troubleshooting, and concrete pumpability. His technical work includes characterization of concrete air void system and assessment of freeze-thaw durability, implementation of new technologies in concrete mixture design, and use of novel test methods and characterization technique of construction materials. At CTLGroup, Dr. Vosahlik’s main focus is on design, development and troubleshooting of concrete mixtures, solving construction-related issues, deployment of new products in the construction industry, and research & development. Prior to joining CTLGroup, Dr. Vosahlik was a research assistant at Kansas State University. While there, he conducted research projects focused on improving construction practices and durability of local infrastructure.


Jose Pacheco

Dr. Pacheco has expertise in the development of high performance and conventional concrete mixtures for construction; construction troubleshooting; assessment and evaluation of concrete degradation mechanisms; and service life predictions for new and existing concrete structures. His other areas of technical work include moisture and transport properties of concrete, volumetric changes of concrete (creep & shrinkage), internal curing, and advanced characterization techniques. Dr. Pacheco specializes in providing solutions for asset owners, engineering firms, and contractors on several subjects including the selection and evaluation of construction materials, construction troubleshooting, durability performance of existing concrete and steel structures, and the selection of repair and mitigation techniques for extending service life. Prior to working at CTLGroup, Dr. Pacheco worked at the Dutch Institute of Applied Sciences (TNO) in the Netherlands as a consultant on civil engineering projects. His work focused on concrete durability and degradation, concrete materials evaluation, and concrete repair.


Please register by Monday, November 11th. If you are a Member, remember to login first to receive the member price. If you have any questions, please e-mail [email protected]


$65.00 Non-Member Attendee

$55.00 Member