An Application of Computer‐Aided Molecular Design (CAMD) Using the Signature Molecular Descriptor–Part 2. Evaluating Newly Identified Surface Tension‐Reducing Substances for Potential Use as Shrinkage‐Reducing Admixtures

Abstract

In this study, the use of computer-aided molecular design (CAMD) is validated as a tool for enabling the discovery of new shrinkage-reducing compounds for possible use in portland cement composites and is framed as one of many multiscale modeling tools in a broad hierarchy of possibilities. Twelve additives were tested for their ability to inhibit shrinkage in Type I ordinary portland cement under both autogenous and drying conditions. The 12 additives included two commercial shrinkage-reducing admixtures (SRAs), two active ingredients of a commercial admixture [one of which was used to establish the quantitative structure-property relationships (QSPR)], two additional classified as potential SRA compounds based on the patent literature, four newly identified compounds predicted by using CAMD and an inverse quantitative structure-property relationship (I-QSPR), and two other compounds use to establish the QSPR relationship. The newly identified I-QSPR compounds were targeted for their ability to reduce the surface tension of water, a primary consideration for shrinkage-reducing activity. Results for both drying shrinkage and autogenous shrinkage indicate that the designed compounds perform similar to commercial admixtures, yet have different chemical functionalities. Hydration data and set measurements were also considered since selection of new SRAs is a multiparameter problem with many constraints. Thus, these newly identified shrinkage-reducing compounds can potentially provide additional options for use in portland cement concrete applications.

Cements in the 21st century: Challenges, perspectives, and opportunities

“…In an effort to streamline and accelerate the discovery of admixture molecules, Kayello et al . and Shlonimskaya et al . introduced an inverse design strategy based on the use of a coarse‐grain molecular‐scale quantitative structure activity relationship (QSAR).…”

“…Some applications of ML to cementitious materials and related chemical admixtures have been made already, and they provide a glimpse of the latent power and flexibility of such methods for designing cementitious composites when sufficient training data are available. Phase segmentation of cement powder microstructures is now routinely accomplished by unsupervised ML, using clustering algorithms trained on subsets of 2D backscattered electron micrographs and X‐ray microanalysis data of polished cement powder cross sections .…”

Fully Automated Molecular Design with Atomic Resolution for Desired Thermophysical Properties

“…Therefore, the CAMD problem can be resolved without reconstructing the 3D structure as in the GC approach. QSPR based CAMD has been applied for chemicals with desired surface tension, , toxicity, octanol–water partition coefficient, and drug design . It is useful to note that the focus of research for CAMD based on QSPR was often on the development of search algorithms. , …”

Behavior of organic compounds in the pore solution of cement—experimental and molecular dynamics study

“…The active agents in SRAs are shrinkage reducing agents (SRas) that are amphiphilic organic compounds . By reducing the surface tension of the pore water, the SRa effectively decreases the magnitude of the capillary stresses and shrinkage strains that arise as pores become partially dehydrated due to either evaporative drying or autogenous effects …”