Efflorescence Control Admixture

Product Description

OPTEC® EC-191 admixture is specially formulated to control primary efflorescence by reacting with alkaline salts before water can solubilize them. It is a ready-to-use admixture to enhance the quality and appearance of masonry units.

Product Advantages

  • Controls primary and secondary efflorescence
  • Improves color consistency
  • Provides short-term water repellency
  • Reduces culls

Product Uses

OPTEC® EC-191 admixture is designed for the production of concrete pavers and segmental retaining wall units, but it can also be used in other low or zero slump machined concrete products such as architectural concrete masonry units and concrete brick.

Application Information

OPTEC® EC-191 is compatible with most concrete admixtures. However, when multiple admixtures are used, they must be added separately to the concrete mixture.

Addition Rates:

OPTEC® EC-191 admixture is typically used at a rate of 3 -10 oz/ cwt (195 -650 mL/100 kg) of cementitious materials, including pozzolans. The addition rate is dependent upon the specific set of materials and the desired end properties.

Mixing Procedure:

For maximum performance, add OPTEC® EC-191 admixture to the aggregate. As with all admixtures, do not add OPTEC® EC-191 admixture to dry cement. Allow OPTEC® EC-191 admixture to mix for 30 seconds before adding the cement. If OPTEC® EC-191 admixture is added to the concrete mixture at any other time, allow an additional 60-120 seconds mix time after all the admixture has been added.


OPTEC® EC-191 admixture is available in drums and returnable totes.

Health & Safety

All precautions defined on the SDS (Safety Data Sheet) for OPTEC® EC-191 admixture must be followed.


OPTEC® EC-191 admixture will be negatively affected at temperatures below 50 °F (10 °C). If this occurs, bring OPTEC® EC-191 to ambient temperatures above 50 °F (10 °C) and thoroughly mix with mechanical agitation before use.


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We hope the information here will be helpful. It is based on data and knowledge considered to be true and accurate, and is offered for consideration, investigation and verification by the user, but we do not warrant the results to be obtained. Please read all statements, recommendations, and suggestions in conjunction with our conditions of sale, which apply to all goods supplied by us. No statement, recommendation, or suggestion is intended for any use that would infringe any patent, copyright, or other third party right.

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GCP Applied Technologies Inc., 2325 Lakeview Parkway, Suite 475, Alpharetta, GA 30009, USA
GCP Canada, Inc., 294 Clements Road, West, Ajax, Ontario, Canada L1S 3C6.
This document is only current as of the last updated date stated below and is valid only for use in the Canada. It is important that you always refer to the currently available information at the URL below to provide the most current product information at the time of use. Additional literature such as Contractor Manuals, Technical Bulletins, Detail Drawings and detailing recommendations and other relevant documents are also available on www.gcpat.com. Information found on other websites must not be relied upon, as they may not be up-to-date or applicable to the conditions in your location and we do not accept any responsibility for their content. If there are any conflicts or if you need more information, please contact GCP Customer Service.

Last Updated: 2024-06-21