Efflorescence control admixture

Product Description

OPTEC® EC-365 admixture is specially formulated to enhance the physical properties and overall appearance of concrete pavers and segmental retaining wall (SRW) units. OPTEC® EC-365 enhances color dispersion and helps minimize both primary and secondary efflorescence. OPTEC® EC-365 admixture improves compaction and densifies the concrete structure, producing a unit with higher compressive strengths, lower absorption, sharper corners and edges and better overall appearance.

Product Function

OPTEC® EC-365 contains additives that chemically react with cement, filling the pores of the concrete with a water insoluble component. This makes the concrete hydrophobic. In addition, wetting agents create a plasticizing effect that densifies the concrete structure. The result is a unit with higher strength, lower absorption, improved appearance, and reduced efflorescence.

Application Information

Addition Rates

OPTEC® EC-365 admixture is typically used at a rate of 4–10 oz/ cwt (260–650 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

OPTEC® EC-365 admixture should be added separately to the mix after the initial wetting of the cement and before, or with the addition of, the final mix water. Once it is batched, it should be mixed for a minimum of one minute, but preferably two minutes. Mix times of less than one minute should be avoided. Never add OPTEC® EC-365 admixture to dry cement.

Product Advantages

  • Reduced absorption
  • Reduced efflorescence
  • Improved color density
  • Increased compressive strength
  • Improved cycle time

Health & Safety

All precautions defined on the SDS (Safety Data Sheet) for OPTEC® EC-365 admixture must be followed.


OPTEC® EC-365 admixture is available in drums and returnable totes.


OPTEC® EC-365 admixture must be protected from freezing at temperatures of 32 ºF (0 ºC) and below, as the admixture is not usable once frozen.

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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.

OPTEC is a trademark, which may be registered in the United States and/or other countries, of GCP Applied Technologies Inc. This trademark list has been compiled using available published information as of the publication date and may not accurately reflect current trademark ownership or status.

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GCP Applied Technologies Inc., 62 Whittemore Avenue, Cambridge, MA 02140 USA.

In Canada, 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 United States. 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: 2020-01-16