Glass Aggregate in Concrete: How to Use it?

Concrete typically is a mixture of sand (fine aggregates) and different sizes of stone and gravel. However, with increasing environmental concerns, recycled materials are used as substitute materials to save resources.

Do you want your concrete to sparkle and shine truly? If so, adding glass aggregates to concrete is the ideal solution. Recent technology even shows that many worldwide manufacturers commonly use glass aggregate. Different glass options are being used as aggregates to replace part or all of the sand and gravel in the concrete to give the surface a unique finish and glow. Let’s explore how glass aggregate can be used in concrete.

Is it Possible to Use Crushed Glass in Concrete?

Although using glass aggregates doesn’t present any significant issues regarding the quality and usability of concrete, contractors must use clean glass in concrete to prevent problems concerning an alkali-silica reaction between the cement and glass aggregates.

Technology advancements have made it possible to crush and clean the glass aggregate collected from post-industrial sources for indoor applications, like terrazzo and concrete countertops or floors. Glass aggregates are available in several colour options and add green value to a concrete surface.

Benefits of Using Glass Aggregates in Concrete

Many people and manufacturers are trying to save the environment by using recycled materials as an aggregate in concrete surfaces. It contributes to reduced consumption of natural aggregate in substantial quantities. Even studies have shown that using recycled glass either partially or totally as a replacement for natural sand aggregate adds more strength to concrete surfaces than other recycled aggregates.

Moreover, the glass aggregate gives an exceptional glow and finish to the concrete surface, making your interior and exterior look more appealing and modern. Glass aggregates, being the cheaper and easily available option, contribute to better durability and provide more robustness to the concrete. Moreover, these recycled aggregates come in many colour options and sizes per your requirements. Glass aggregates in concrete are more commonly used for flooring and countertops.

Grading Glass Aggregate by Colour and Size for Concrete

If you consider using glass aggregates in a concrete finish, the aggregates’ size and colour are two vital considerations.

Manufacturers typically grade glass aggregates by colour and size. Their size can range from fine-talc-like powder to gravel-sized pieces to six-inch glass stones. Many techniques, including polishing, grinding, and other exposed aggregate techniques, are used to reveal the glass. Contractors sometimes seed the glass on the surface and expose it using various methods.

Glass is appealing to contractors because of its availability in varied colour options. You can find glass aggregates in various colour options that can’t be found among marble or gravel chips. Glass aggregates are available in multiple colours, including brown, blue, red, green, yellow, and others.

Talking about composition, contractors can coordinate coloured glass with the matrix of integrally coloured concrete. For instance, lighter-coloured glass can be used in darker matrices and vice-versa. Moreover, using dark brown glass in a dark brown matrix can create a stunning look. A clear glass aggregate can reflect the matrix’s colour, adding more depth to the surface. Since glass is acid-resistant, acid staining can colour the surrounding matrix without compromising the aggregate’s colour.

Furthermore, finely ground glass aggregate can add background colours to the concrete matrix while creating highly polished finishes. Studies even show that finely ground glass aggregate can increase workability and decrease the cost, time, and energy to install the concrete surface while achieving a highly polished surface with exceptional strengths.

Using Specialty Glass Aggregates

Specialty glass aggregates are made using recycled glass that is melted down and re-formed to give a different look than plain old crushed glass. Crushed window and bottle glass are flat, with parallel sides. On the other hand, specialty glass aggregates can feature fuller, more irregular shapes, like crushed gravel.

Adding a Little Sparkle

Sparkle notwithstanding, you can find some decorative concrete artisans preferring cullet because it needs less polishing or grinding to bring out aggregate’s flat pieces than it does to reveal more multidimensional aggregate.

You can use finely ground mirror aggregates to add a little sparkle to your concrete surface. Mirror chips can give the surface a hard reflective shine compared to a finely ground mirror aggregate that adds a subtle iridescent sheen. Moreover, using a 30-mesh mirror or smaller and putting it in the background matrix can give the concrete surface a sheen-like granite.

Can You Use Glass Aggregate in Outdoor Concrete Applications?

Many studies have been conducted on the usage of glass aggregate in concrete. Some studies showed that using glass aggregates for outdoor concrete applications can result in an alkali-silica reaction, especially when exposed to moisture.

The alkali in cement and the silica in the glass can form a gel that swells when they come into contact with moisture. Due to this reaction, cracks are formed in the concrete surfaces mixed with glass aggregates.

Is there any way to prevent or stop this alkali-silica reaction?

You can stop this alkali-silica reaction and use glass aggregate in the outdoor porcelain tiles. All you need to do is apply a good sealer to keep out moisture and, thus, suppress the reaction (presuming that too much water hasn’t been used in the mix). Alternatively, the contractor can use met kaolin to stop the reaction or grind the recycled glass finely to pass smaller screens.

To wrap up!

These days, you can find post-industrial and post-consumer recycled aggregates being crushed, processed, cleaned, and packaged that contractors and builders purchase for concrete applications.

From finely ground glass to glass chippings, glass aggregates are used as alternatives to sand and gravel to add more strength, workability, durability, shine, and glow to concrete surfaces. Regarding glass aggregates in concrete surfaces, the most common applications include countertops, walls, floors, and other concrete decorative designs.

So, a crushed glass aggregate mix is the optimal solution if you desire to produce a beautiful, durable, low-maintenance concrete surface. Moreover, this recycled material is available in many colours and sizes to help you create an aesthetically appealing and environmentally friendly space.