When people talk about ‘green’ solutions or ‘green’ alternatives the term is sometimes used quite loosely.

In order to replace or upgrade existing systems, and be employed on a broader scale, ‘green’ options need to be sustainable, simple to implement, do no (or less) damage to the environment, and perhaps most importantly they need to be cost effective. If an eco-friendly choice is available that saves time and money it will quickly be adopted; often the only drawback is a lack of knowledge.

A.M. Machado has taken it upon themselves to close this information gap and be a bridge linking contractors to high quality products and systems for road building, maintenance and rehabilitation.

With the support of the Zimbabwean Ministry of Transport the new system is definitely the road forward. It’s common knowledge that many roads in the country are in urgent need of attention. The current traditional methods of building new roads or repairing existing ones is extremely expensive and relatively slow.

To build a new road in the traditional way consists of grading and levelling the soil, applying two or more layers of aggregate and then compacting the gravel, often using cement as a binder or stabiliser. Cement takes weeks to cure so the process is slow. Only then can the road be surfaced with asphalt.

Depending on the soil type, environmental factors and the type of road the cost can be around one million US dollars per kilometre.

The new methods that A.M. Machado is popularising and championing are much cheaper and quicker, as well as being carbon negative–much kinder to the environment. The method makes use of materials found on site so there’s no need to quarry and transport tonnes of aggregates, saving fuel costs and reducing carbon emissions, it also saves on wear and tear on vehicles; it uses much less water and because the main components of the stabilisers are made from naturally occurring materials, it actually sequesters carbon in the road sub-structure.

Carbon Crushers uses lignin which is the organic polymer found in plants to make them ridged and woody. It’s usually sourced from the timber industry or paper recycling (another green credential).

In Zimbabwe research is underway to obtain lignin from the waste produced by the sugarcane industry. To explain the new process very simply – a crusher digs up the surface of the existing road (including old asphalt, soil and rocks) to depth of around 35cms to create a homogenous substrate. The stabiliser is then applied using a water bowser, the road graded and compacted and can then be open for traffic or for surfacing with asphalt.

Even without asphalt capping the road surface is smooth and predominantly dust free, reducing wear and tear on vehicle traffic, and requiring very little maintenance for many years. The method uses existing road construction machinery so no additional special equipment is needed.

Cypher Environmental Products are an ideal system for mine roads as well as for open cast mining, tailing pipes and stock piles. The surface is weather resistant and doesn’t become muddy in the rainy season. It’s also suitable for airport runways and for farm roads. A.M. Machado has been liaising for a few years with two main proponents of this method of road construction–Canadian firm Cypher Environmental Products and Carbon Crusher Services and Bio Binders, based in Norway.

A.M. Machado has been a local agent for Cypher Environmental Products since 2018 and, in 2020 set up a sole distribution agreement. Cypher provides two main products: ROAD// STABILIZR (formerly called EARTHZYME) and DUST/BLOKR both ideal for construction and rehabilitation of existing roads and particularly suitable for the mining industry.

ROAD//STABILIZR

• Requires 20%+ clay content in soil
• Long-lasting results: 10+ years with a single application and no additional grading
• Up to 3x harder than concrete, self-healing
• 1 litre can treat up to 33m3 of soil
• Airfreight is cost effective
• Doesn’t wash away in heavy rains
• Environmentally friendly, non-toxic & non corrosive

DUST/BLOKR

• Can be used with any soil or material type
• Results seen lasting up to 3-4 years with proper maintenance before re-grading needed
• Highly water resistant – won’t wash away in rainy season
• Environmentally friendly, non-toxic & non corrosive Cypher Environmental Products has received confirmation of Boeing BSS7432 (D6-14787) Conformity for both ROAD// STABILIZR and DUST/BLOKR.

With these results in mind, clients in the aviation industry can be assured that their aircraft will not be exposed to any corrosion damage.For clients in other industries, like mining and farming, that use expensive equipment and tools, they can also be assured that the products will not damage their assets. Many projects can use a combination of both products to create resilient surfaces with minimal dust generation.

A.M. Machado has been proposing that DUST/BLOKR is so effective that it should be used on the detours along the new Bulawayo-Victoria Falls highway to reduce dust. The soil in that area is classified as Kalahari Sand which is notoriously one of the most unstable and difficult soil types to work with.

Without the use of DUST/ BLOKR, gravel that had been transported to site for the construction of the main road was being diverted to the detours, so the use of DUST/BLOKR could significantly reduce material and transport costs.

In an urban setting ROAD// STABILIZR was recently used for the rehabilitation of Willowmead Lane in Rolf Valley in Harare. The road had not been repaired for at least 15 years and was in an almost impassable state. The Willowmead Lane Community got together with Cypher and Bitumen World and under the guidance of the City Council (and with the approval of EMA) the road was quickly and economically completely repaired and has been maintenance free for a number of years.

One the outstanding benefits of ROAD//STABILIZR is that with heavy traffic it actually becomes stronger as it gets more compressed.

Cost reduction using the ROAD//STABILIZR method – 12+% in building new roads, 17% in fuel used for transportation and construction. Using DUST/ BLOKR – 85% reduction in water and fuel savings.

The following quote is directly from Cypher Environmental Product’s website: “Your bottom line is not only important to us, it’s our promise. How? By enhancing the engineering properties of your roads, you can reduce fuel consumption, increase tyre life and reduce maintenance costs on vehicles.
Not to mention substantial cost savings in maintaining treated roads. Entire communities benefit from enhanced roads which translates to more
cost-effective transport of goods, technology and people while being kind to mother nature.”

Norwegian based Carbon Crusher Services and Bio Binders uses a similar method. The company is about to receive Verra accreditation, which is the global regulator for climate action and carbon standards, so it really is a ‘green’ company.

Carbon Crusher Services and Bio Binders is committed to producing climate resilient roads with higher carrying capacity and which are carbon negative. Carbon Crusher has been developing roads that not only store carbon but also avoid emissions from the traditional way of building roads.
This exciting advancement empowers local contractors to contribute to our country’s Nationally Determined Contributions; Zimbabwe has committed to reducing its emissions by 40%. It is an example of how private companies can drive national ambition.

Vigorous scientific and technical research, listed on their website, claims, Our carbon negative roads store 51 tonnes CO2 per mile road.
Regular methods add ~100 tonnes CO2 per mile road. In total, 150 tonnes CO2 per mile road which is reduced from the atmosphere.

These are impressive statistics even for an environmentally friendly company! An important preparatory step for their method is to ensure that there is adequate drainage for water runoff and that all drains, gutters and culverts are cleared. Excess water will damage any road.

For upgrading or refurbishing of an existing road Carbon Crusher employs a specialised in house designed crushing machine which recycles the existing road surface crushing up asphalt and soil and stones on site to a specified aggregate size and to a depth of 25 to 35 cms. Conventional methods require the old road surface to be hauled away and either recycled or dumped so reusing the previous material on site saves the cost of taking the material away and hauling new aggregates in – also reducing emissions from the fuel used.

It also works on gravel roads without asphalt paving, making it well-suited to mining, forestry and rural roads. The binder is sometimes used at this stage and works well on fine or coarse-graded material.

The method also only requires one lane of traffic to be closed at a time minimizing inconvenience and maintaining traffic flow. Once the road surface has been crushed to the required aggregate size a conventional grader is used to ensure all the material is incorporated and to determine the camber of the surface.

Compaction of the road is performed using a steel drum roller. Stabilisation is then carried out applying the dry environmentally friendly and non-toxic binder mixed with water and sprayed onto the surface from a bowser followed by a mixer. A second phase of grading adjusts the camber and ensures a smooth surface. Final compaction is done, usually in two or three passes.

The degree of compaction is monitored and recorded by the compactor. Normal cars can then immediately drive on the road while heavy vehicles should be limited for 3-7 days for the curing to take place.

If the client requests it, a layer of asphalt can then be applied in the conventional way to cap the road. Carbon Crushers employs the first AI enabled road management dashboard called SkyRoads a software that facilitates and optimises road manintenece by continuously monitoring the condition of the finished road and indicating where problems may arise and need attention or maintenance.

The method saves time and optimises resource allocation and is convenient to ensure ongoing traffic use during construction. Carbon Crusher has also received an Environmental Product Declaration across Norway and the United States of America; third party verification that demonstrates that their roads do indeed store carbon upholding their carbon negative status. A.M. Machado is continuously striving to engage strategic partners such as Carbon Crusher and Cypher Environmental and be the bridge between global innovation and local road construction companies.

With the ongoing support of the Ministry of Transport and EMA, the road to a greener future seems to be clear. A.M. Machado together with Carbon Crushers’ and Cypher’s engineers will take soil samples to determine the best use of their respective products and tailor-make the optimum method and resulting services. The built environment can have a significant impact in reducing Greenhouse Gas Emmisions, conserving ecosystems and making corporate decisions that do not compromise future generations. A.M. Machado has posed a question to the industry, “We are going green, are you?”

You can contact A.M. Machado for more information:

phone +263 24 2486640 or +263 7722 78472, email: alexandre@ammachado.com website: https://ammachado.com/
They are located at 15 Neill Avenue, Harare, Zimbabwe

Read Issue 80