Fingerprinting of Chemical Admixtures in Fresh Portland Cement Concrete by Portable Infrared Spectrometer

The ongoing second SHRP 2 R06-B project entitled Evaluating Applications of Field Spectroscopy Devices to Fingerprint Commonly Used Construction Materials conducted at the University of Connecticut targets, among other objectives, the identification and quantification of chemical admixtures in portland cement concrete (PCC). The two specific objectives for the PCC study are (a) the applicability of portable infrared spectrometers for identification of the admixtures in fresh concrete under field conditions and (b) the feasibility of tracking interaction between hydration products during PCC setting. In the first phase of the study, four admixtures (air entrainer, retarder, accelerator, and superplasticizer) were tested to establish their chemical signature in the infrared and ultraviolet regions of the electromagnetic spectrum. The fingerprinting of the admixtures was performed with a portable attenuated total reflection (ATR) Fourier transform infrared spectrometer. The second phase concerned evaluating ...