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RECYCLING OF

BUILDERS RUBBLE

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The mission

Introducing recycled/processed builder rubble into the Civil and Construction markets

Challenges experienced to date:

• Sorting materials from source

• Changing the current mindset

• sensitivity / distribution / capacity building

towards utilization of construction &

demolition waste

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Woolworths Distribution Centre, Montague

Gardens, Cape TownMaterials Recovered

Concrete – fences, casting beds, pipes 4500 m3

Brickwork 3500 m3 Construction of local school

Asphalt 2600 m3 Returned to Much Asphalt for re-use

Laterite from excavations 6800 m3

Construction Materials

Crushed concrete was applied in the base layers of the 30 000 m2

warehouse building, while recovered brick was used to build a local

school. All windows and doors were diverted to a salvage store. As

such more than 90% of the waste generated by the demolition was

re-used, with resulting cost savings for all projects involved as well

as conservation of landfill airspace and avoided greenhouse gas

emissions that are associated with the extraction, processing and

transport of virgin construction materials.

Savings

Material cost savings:

4500 m3 at R130/m3 for G5 = R585 000, excluding transport

Landfill fees savings* on 17 400 m3, at 1.6 t per m3 and R400/t = R1.1

million if the material was disposed of at landfill, rather than

stockpiled.

*R0 if clean loads, but at City of Cape Town landfills ~R400/t covers

operational costs.

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Overstrand Municipality – a berm of builders’ rubble in Hermanus was created as a barrier between formal and informal residential areas. As part of building community in the

area, the municipality wanted the berm removed.

Iselula Crushing was able to provide the service by crushing and using the material in construction projects in the area, including fill material for a secondary school site in

Stilbaai, fill and G5 material for roads and parking lots at a school in Hermanus, as well as sidewalks on various projects. Screened filling was also used by WA Bishops Transport for various projects around Hermanus and oversize/ pioneer aggregate

was screened for use as drainage at the mall.

Materials recovered:19 600 tonnes of rubble was processed and removed from the site.

Saving: Landfill cost savings: Operational costs in Overstrand for 19 600 tonnes of rubble would have been R6 800 000 @ R340/t, excluding loading and transport costs.

Material cost savings: R2 395 000 (Cost of virgin material less the cost to crush and re-use builders rubble)

Hermanus berm – given a ‘new life’ in Overstrand

Municipality’s headache is construction industry’s

treasure

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Project description –Blackheath processing plant

This materials hub receives between 5 700 and 22 000 m3 of builders’ rubble

per month from local demolition and construction companies. Concrete, bricks

and mortar are processed on-site to produce G4, G5, G7, G9 and kerbmix.

Although originally seen as ‘contaminants’ in an aggregate producing business,

other materials delivered to site have generated income opportunities for the

surrounding community.

Benefits

Income opportunities

There are 32 formally employed staff on-site

Further income opportunities are available for 14 individuals in informal

businesses

Landfill diversion

Between 5 700 and 22 000 m3 of ‘waste’ is diverted from landfill every month

(this probably also partly represents a saving of illegally dumped material).

In the City of Cape Town, landfill operating costs are about R400/t, so assuming

a bulk density of 1.6t/m3, between R3.6 and R14 million in landfill operating

costs are saved every month.

Iselula Crushing – Blackheath siteA secondary materials’ ecosystem

Benefits in using recycled aggregates

1. Reduced tippage and related freight charges

2. Cheaper source of aggregate than newly mined

3. Reduction of landfill space required for rubble debris

4. Reduced haulage costs

5. Recycling also saves energy that would otherwise be

used to mine, process, or transport new aggregates,

which is also beneficial to the environment.

6. Produce specification size aggregates at own location.

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Ensuring the Quality of recycled building rubble

1. Constant testing by SANAS approved

labs is required to ensure minimum

requirements are met.

2. Separation/sorting at source.

3. Quality control process control

implemented to ensure all grades of

aggregates.

4. Separation prior to crushing.

5. Quality control methodology once

processed.

6. Faster construction if in-place

recycling methods are employeed.

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Current recycled aggregates being used in the market

G7(filling) G6 (fill-63)

G5 (Sub-

Subbase-53) Kerb-mix Pioneer Layer