Grace Construction Products has unveiled for producer use the AdiaCal portable field calorimeter, which for the past few years has been used primarily
Grace Construction Products has unveiled for producer use the AdiaCal portable field calorimeter, which for the past few years has been used primarily by field staff testing various binding agents and admixtures. Company officials cite improvement in daily concrete quality control methods as the device enables producers to test mix designs by sampling directly from the mixer or batch plant. By measuring a target mix’s heat signature, users can gauge strength and performance potential of combinations of differing cements, supplementary cementitious materials and admixtures.
AdiaCal testing capabilities help users identify potential problems at the plant before they surface as job site issues, Grace engineers affirm. The device allows producers to prevent set time problems by comparing mixes using multiple sources of cement; different brands or types of admixtures and dosing schedules; and, various fly ash or slag contents. Moreover, company engineers note, the calorimeter helps producers develop the most efficient mix design through prescreening cement, fly ash, and slag sources; determining the optimum admixture dosage with various cements; identifying adverse interactions between materials; and, verifying maximum admixture dose for top performance.
AdiaCal works by measuring specimen temperatures in insulated cylinders to determine early hydration reactions, and thus relative performance, of various concrete mixes. Designed for portability, economy and easy of use, product developers emphasize, the luggage-sized, four- or eight-specimen unit connects to a computer via a USB port and can be set up in the field or in a laboratory. Data is then collected and displayed by Grace’s proprietary software. Results appearing on the computer screen as a heat signature can be interpreted by the quality control manager within hours. Because data collected during a test is stored directly in the AdiaCal unit, no computer need be tied into the device.
ADIACAL FIELD CALORIMETRY
TYPICAL HEAT SIGNATURE
Heat signature is the graphical representation of concrete hydration temperature over time. The curve can be used to evaluate a mix or troubleshoot problems.
A – Initial concrete mix temperature
B – Dormant period, allows for concrete transport, placing, controlled by admixture type and dose
C – Approximate point of first set
D – Approximate point of final set
E- Most of the broad heat rise comes from strength-giving alite hydration