You are here

Mechanisms of Hydration and Setting of Ordinary Portland Cement in Simple and Complex Systems

Project Information

Project Status: 
Completed
Start Date: 
Thursday, July 5, 2012
End Date: 
Sunday, June 4, 2017
FHWA Program: 
Exploratory Advanced Research
FHWA Topics: 
Material Science

Contact Information

First Name: 
Richard
Last Name: 
Meininger
Telephone: 
(202) 493-3191
Team: 
Office of Infrastructure Research and Development
Office:
Office of Research, Development, and Technology

Project Details

Project Description: 

The focus of this project was on clearly defining the causes of the onset and end of the induction period of alite, which controls set, strength, and subsequent microstructural development. The researchers simulated the presence of mineral and chemical admixtures by introducing aluminate and sulfate ions and organic retarders at ratios known to perturb normal hydration. They used new experimental methods capable of measuring chemical and microstructural changes on the nanometer to micron scale during hydration. The goal is to use this insight to improve the ability of the National Institute of Standards and Technology's (NIST’s) HydratiCA model to predict hydration kinetics and microstructure in the presence of supplementary cementitious materials, such as fly ash, slag, and metakaolin, as well as organic admixtures. This detailed understanding also will lead to improvement of the boundary nucleation and growth (BNG) model to permit prediction of hydration kinetics and setting behavior in a software tool that is powerful but simple enough to be used in the field.

Project Findings: 

This project's breakthroughs in the measurement and analysis of concrete materials are matched by modeling advances that help researchers better design and interpret experiments. The resulting new understanding of hydration mechanisms and development has been used by the project researchers to improve the HydratiCA model developed by NIST, which is currently the most sophisticated tool for simulating hydration. The improved model will be able to generate both microscale and macroscale predictions of hydration behavior under a much wider range of conditions than previously possible. Researchers also have developed SimBNG, a boundary nucleation and growth model that is powerful but also fast enough and simple enough to be used in the field.

Deliverables

Deliverable Name: 
Mechanisms of Hydration and Setting of Ordinary Portland Cement in Simple and Complex Systems Research Summary Report
Deliverable Type: 
Techbrief
Deliverable Description: 
This research summary report provides a description of research carried out to improve the understanding of the mechanisms of hydration of portland cement in complex and simple mixtures; develop analytical methods to directly observe hydration processes in real time; and develop and validate improved computer models to design optimal concrete composition, curing methods, performance, and durability. The project resulted in innovative analytical techniques that made it possible to perform direct micro- and nanoscale observation of reactions. This new perspective allowed researchers to develop a new and clearer hypothesis to understand the mechanisms of cement hydration. Computer models based on the new hypothesis will provide engineers and practitioners with tools to produce more efficient, durable, and cost-effective concrete products and structures.