Controlled release of chemical admixtures

Highlights

A controlled release formulation for a cement-based composition can be produced by including an admixture (e.g. an accelerator, a set retarder, or a superplasticizer) for the cement-based composition into a layered inorganic material. A cement-based composition containing a material like cement, mortar or concrete and a controlled-release formulation has better workability, especially in respect of slump-loss characteristics. With such a formulation, release of an admixture in a cement-based composition may be controlled.

Technology transfer

This technology is available for licensing, or for further development through a collaborative research agreement with NRC. The business opportunity may be referred to by its NRC ID: 11353.

Market applications

This innovation is of particular interest to cement and specialty chemical manufacturers and can be used to develop effective concrete products and new, inexpensive materials for the programmed delivery and action control of admixtures in cement-based compositions.

Other areas of high demand for this innovation include the agricultural field as an agrochemical carrier for plant growth and herbicides against fungi and other pathogens. There is also the potential for application in the pharmaceutical/medical fields for the delivery of bioactive drugs.

How it works

Admixtures like accelerators, set retarders or superplasticizers are often added to cement-based compositions to improve the properties of concrete. Admixtures are most often added at time of mixing, which is not necessarily optimal for the desired chemical effects. It is often desirable to delay release of these compounds to control workability

In the past, encapsulation procedures were used for delayed delivery of admixtures, however these methods are time consuming and expensive. This innovation enables development of new, inexpensive materials for programmed delivery and action control of admixtures in cement-based compositions.

This technology includes a method for controlling release of an admixture in a cement-based composition. The method consists of first inserting the admixture into a layered inorganic material to form a controlled-release formulation and then adding the controlled-release formulation to a cement-based material. Cement-based composition is also provided as part of the invention. Lastly, a method for controlling release of an admixture in a cement-based composition is described.

The technology represents a nanotechnology approach to control the delivery of admixtures in cement-based compositions. Release of the admixture can be actively programmed through controlled chemistry involving, for example, the type of layered inorganic material used, charge density, concentration, and/or the pH.

This method allows for the in situ, real-time delivery of admixtures to cement-based compositions to enhance the performance of admixtures and cement-based products containing them, such as the improved modulation of slump loss.

Benefits

Lower cost materials for actively programmed, controlled release of admixtures in cement-based compositions, leading to concrete with improved properties like workability, slump-loss, corrosion resistance, or freeze-thaw properties.

Patents

NRC file 11353: https://www.google.com/patents/CA2554347A1

Patents are granted in Canada and US.

Contact

Tony Jenkins, Portfolio Business Advisor
Telephone: 613-990-8084
EmailTony.Jenkins@nrc-cnrc.gc.ca