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 super-plasticizer) 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 freshly mixed PCC samples prepared with each admixture separately in the amount prescribed by the manufacturer. Chemical changes in the PCC samples were tracked over the 6-h period by the portable ATR spectrometer. Quantitative analysis of the ATR spectra allowed for evaluating the effect of chemical admixtures on hydration activity in PCC.