Landscaping Concrete needs to be the correct grade with the correct reinforcement for the job it is selected for. Otherwise cracking can occur. To properly decide on which mix to use, it is important to understand what it is and what factors affect its physical properties. There are many different grades of concrete available, so it important to pick the correct one for the job. Coupled with this there are different grades of steel reinforcement to choose from.

Pre-mixed Multipurpose Concrete for garden walls

 

Garden Paving

Bending stresses are not normally a problem with garden paving when a properly prepared sub base has been created. Steel reinforcement will however, help to prevent cracks opening in the pavement.

Generally, the path should be at least 100mm thick N25 concrete. N25 means that the concrete will achieve a compressive strength of 25 mPa after 28 days. If you are in a part of Melbourne with a reactive clay soil, you need to ensure there is sufficient thickness of roadbase under the paving to cope with the expansion and contraction of the soil.

Preventing Cracks in landscaping concrete.

Even the strongest concrete will be weak in tension or bending and even properly cured concrete will have microcracks. Therefore, to minimise cracking steel reinforcement must be used. For pathways, this should be at least SL 72 using saddles to keep it in the top 1/3 of the concrete.  SL72 means that the bars are each 7mm in diameter with grids of 200mm. The path should be laid on 100mm thick class 3 roadbase , if it is for public spaces. If there is any possibility of a vehicle driving on the path, then the path needs to be built like an exposed aggregate concrete driveway. This will be the case with any vehicle crossovers in the path design. In these cases the concrete needs to be at lease 125mm thick N32 (32mPa) concrete with SL92 mesh laid on at least 100mm of class 2 roadbase.

Landscaping concrete. Steel reinforcement helps to prevent large cracks opening up in your concrete.

For paving, the steel mesh should be placed about 30mm from the top surface. When reinforcement steel is placed too near the surface, it can corrode. Expansion results as steel is converted to iron oxide through corrosion. This expansion can crack the concrete surface and accelerate the concrete cancer.

Concrete block garden retaining wall with coping next to the alternating exposed aggregate path.

Concrete block garden retaining wall with coping next to the alternating exposed aggregate path.

When the crack is caused by corroding steel, corrosion is typically visible at the slab surface. In the case of retaining walls, the wall is in effect a cantilever beam with the soil applying pressure to the wall. Steel reinforcement will help increase bending strength of the wall.

Melbourne Landscaper - Concrete in-situ steps Mill Park Leisure centre.

Melbourne Landscaper – Concrete in-situ steps Mill Park Leisure centre.

Architectural Landscaping Concrete in Melbourne

Modern concrete is now available with an enormous range of colours and textures. There are some available that can mimic the appearance of stone, but at a much lower cost to the landscaper. There are also some techniques by landscape architects to break up a large expanse of concrete by using alternating contrasting colours.

Exposed aggregate Concrete Pathway

Exposed aggregate Concrete Pathway using alternating coloured concrete. The appearance is also softened by the mulched garden bed with plantings of native grasses. These architectural concreting techniques provide a very cost effective solution but maintain the aesthetic appeal.

Related Concrete information from Red’s Landscaping and Civil

Concrete 9 things you need to know

 

In-situ Concrete

 

Concrete Architecture in Landscaping

 

11 Best landscapers of all time.

 

 

 

Contact us

For help with the design  and development or your landscaping ideas, contact one of our experienced Landscape Gardeners.

We can help with small garden design all the way up to  Commercial Landscape design.

Our specialities include fast growing screening plants, plant health and horticulture, garden lighting  and in-situ concreting.

By Callum O’Brien – Landscaper Melbourne

 

 

© 2020 Reds Landscaping and Civil quality commercial landscaping Melbourne

 

For more information on concrete

 

How to minimise thermal cracking

 

How it is made and the scientific principles.