HRMK 100

Uses

HRMK 100 concrete admixture can be used in a wide variety of ready mix and manufactured concrete products and cement based grouts, mortar and stucco. Most typical mixes containing HRMK 100 product will consistently achieve compressive strengths of 6,000 psi (42 MPa) and higher utilizing locally available materials. The addition of HRMK 100 admixture produces concrete with increased water tightness and dramatically reduced permeability compared to conventional mixes. Reduced permeability is an important advantage in slowing the intrusion of chloride where corrosion of reinforcing steel is a potential problem. It also enhances the durability of concrete against aggressive chemical attack and in hydraulic abrasion-erosion applications. This product can also be used to efficiently mitigate alkali-silica reaction in concrete.

Product Advantages

• Increased compressive and flexural strength
• Increased durability and reduced permeability
• Reduced efflorescence and alkali-silica reactivity potential
• Lighter color and increased reflectivity
• Reduction in greenhouse gas emissions compared to 100% cement mixes

Performance

HRMK 100 admixture improves concrete through two primary mechanisms. First, the fine product particles fill the microscopic voids between the cement particles, creating a less permeable structure (often called “the filler effect”). Second, metakaolin reacts with calcium hydroxide (byproduct of the cement hydration process), to form additional calcium silicate hydrate (CSH), producing a tighter paste-to-aggregate bond. In order to meet specified concrete performance levels, however, many variables are involved. These include, but are not limited to; concrete materials, weather conditions, testing techniques and mixing, transporting, placing and finishing practices.

Addition Rates

HRMK 100 admixture dosage rates will vary based on application but typically will range from 4%-15% by weight of cement. A dosage rate of 8%-10% by weight of cement has been shown to optimize pozzolanic reactivity. If the product dosage rates are not specified, consult your GCP Applied Technologies representative to discuss particular job requirements.

Preconstruction Trial Mixes

It is strongly recommended that trial mixes be conducted prior to job start up. This allows the producer an opportunity to optimize HRMK 100 dosage rates, proper batching sequence and other admixture quantities needed in order to deliver a workable concrete mix to the job site. Trial mixes will also help determine whether the combination of concrete materials and construction practices will allow the concrete to meet a specified performance. Contact your GCP Applied Technologies sales representative for help with trial mixes.

Finishing and Curing

HRMK 100 concrete can be used in flatwork with little or no modification to the recommended practices outlined in ACI 302, Guide for Concrete Floor and Slab Construction and ACI 308, Standard Practice for Curing Concrete. This product may reduce surface bleed to some degree. Your GCP Applied Technologies representative is available to review your particular job needs.