Qualities and Uses of Retarding Admixtures for Polished Concrete Finishes

Concrete is a fast-setting material that can often be difficult to work with. When exposed to air and heat, concrete hardens quickly and requires heavy-duty resurfacing or grinding to fix. In building and forming structures, you need more time before the concrete completely sets so you can achieve your desired finish.

To delay the setting process of concrete, you will need a concrete surface retarder.

Understanding Concrete Retarders

A retarder is a type of concrete admixture formed by oxides and acids that retard the initial setting time of concrete for one to three hours. When you slow down the setting period, the concrete mixture stays in a fresh mix state for longer before it solidifies.  

Retarding concrete is beneficial for:

• Offsetting the effects of hot weather
• Preventing cold joint formation
• Large volume pours
• Complex concrete placements and grouting
• Special architectural surface finish
• Allowing long-haul distances

Moulding to Perfection                            

Concrete retarders are valuable for both practical and aesthetic reasons.

When you add the retarder into the concrete mix, you slow the setting process and strengthen your concrete. In fact, many contractors use surface retarders to bring aggregate to the top of the concrete as a protective layer. This prevents the concrete from cracking and crumbling, especially during tough weather conditions.

Retarding admixtures also give concrete a rough-hewn, highly textured appearance that is a desired quality by several contractors and architects. The exposed aggregate finish creates a contemporary industrial look without mimicking brick, tile or stone.

Proper Usage and Storage

At Timberfix, we supply Sika® retarders. The Sika® set-retarding concrete admixture is one of the most efficient options on the market. They are compatible with almost all types of concrete, including sulphate-resisting cement (SRC). The Sika® retarder is commonly used for structural and mass concrete where a controlled extension of setting time is required.

For dosage, add 0.2% to 2.0% of retarding admixture by weight of concrete. The retardation rate achieved is directly dependent on the dosage rate. Experts advise you to execute trial solutions first before formulating the final mix so that you can establish the exact dosage rate that matches your needs.

Add the Sika® retarder with the mixing water only at the end of the mixing process. Cure the concrete properly before applying the retarding admixture. Once you are through with the solution, clean all your tools and equipment with fresh water.

Be sure to store your Sika® retarder in clean, undamaged containers. Keep them in dry conditions and at temperatures between +5°C and +30°C. Protect them from direct sunlight and frost.

Your Trusted Supplier

At Timberfix, we offer top-quality construction and hardware products that you can purchase at competitive prices. Since we are a family business of 3^rd generation builders, we have developed extensive knowledge of the construction sector and have studied the industry’s demands, making sure our products target your requirements.

We also understand the importance of Service. We have a reputation for employing hard-working and helpful staff who are more than willing to help you with your construction needs. Our team specialises in quick deliveries through Sydney, Blue Mountains and New South Wales.

Make Timberfix your partner in construction today.