As infrastructure networks age and traffic demands increase, the long term protection of bridges, overpasses, culverts and other critical concrete structures has become a top priority for engineers and contractors. 

Within the Saint-Gobain group, GCP’s internationally proven waterproofing technologies – available in South Africa through Chryso Southern Africa – are providing advanced solutions for both new construction and rehabilitation projects. These products, including BITUTHENE® 5000 and ELIMINATOR® Bridge Deck Waterproofing, are engineered to extend service life, improve safety and reduce costly maintenance on vital transport infrastructure.

BITUTHENE® 5000 is a heavy duty composite membrane developed for use beneath hot-applied asphalt concrete wearing courses. It incorporates a moisture and water resistant rubberised asphalt layer reinforced with a puncture and heat resistant polypropylene mesh, providing dimensional stability, flexibility and excellent adhesion. 

Supplied in rolls with a protective release paper for easy handling, the membrane is cold applied, requiring no heating or hot bitumen bedding. It is suitable for both new construction and repair applications, offering effective waterproofing for bridges, overpasses and other vehicular traffic structures as well as parking decks.

In rehabilitation projects, BITUTHENE® S5000 strips are recommended for restoring concrete pavements with asphalt overlays, preventing premature deterioration caused by reflection cracking and sub-base erosion. The membrane’s high resistance to water, combined with its ability to remain flexible over extreme service temperatures, ensures performance even during harsh winter cycling over small cracks. 

On structures where detailing is critical, BITUTHENE® Liquid Membranes and BITUTHENE® 5000 Mastic can be used to seal terminations, edges and overlaps, ensuring complete waterproofing integrity.

“BITUTHENE 5000 is designed with the realities of modern infrastructure projects in mind,” Andries Janse van Rensburg, Business Development Manager – Specialty Building Materials at Chryso Southern Africa, says. “Its robust construction, flexibility and proven ability to withstand extreme conditions make it a trusted choice for protecting concrete structures against water ingress and deterioration. The fact that it is cold applied means faster, safer and more consistent installation on site.”

The ELIMINATOR® Bridge Deck Waterproofing membrane offers equally impressive performance for steel and concrete bridges which are constantly exposed to water, chlorides and frost – conditions that can lead to deterioration and even structural failure. 

This cold spray-applied system is based on ESSELAC® advanced resin technology, creating a fully bonded composite layer between the bridge deck, waterproof membrane and asphalt surfacing. The result is a membrane that withstands punishing climate conditions and heavy traffic loads while maintaining its bond and integrity. 

ELIMINATOR® can be applied in virtually any climate, curing in just one hour even in high humidity or low temperatures, preventing costly weather delays and allowing for greater scheduling flexibility. A two colour application process enables on-the-spot quality assurance, while the membrane’s ability to withstand asphalt surfacing temperatures up to 250°C eliminates overcoating time constraints and accelerates project completion.

“ELIMINATOR has a proven global record of protecting thousands of bridges over decades of service,” Janse van Rensburg adds. “Its rapid curing time, adaptability to almost any climate and long term durability are significant advantages for contractors and road authorities who cannot afford prolonged closures or recurring maintenance. It is a cost effective way to protect the substantial investments made in these essential structures.”

With proven track records on thousands of bridge and concrete structures worldwide, both BITUTHENE® 5000 and ELIMINATOR® provide engineers and contractors with reliable long lasting waterproofing systems. Supplied in South Africa by Chryso Southern Africa, these GCP technologies safeguard critical infrastructure against water ingress, chloride attack and freeze-thaw damage, extending service life, enhancing safety and reducing the long term costs associated with maintenance and repair.

As the construction industry intensifies its focus on sustainability, a common challenge has been balancing lower carbon emissions with the need for fast-paced project delivery. Chryso is addressing this issue with its EnviroMix® range – a solution that allows for the use of low-carbon concrete without sacrificing early strength performance.

“Reducing the carbon footprint of buildings is no longer optional – it is becoming a priority for developers and specifiers,” says Patrick Flannigan, Chryso GM Technical and Product Support Management Africa. “But traditional methods for lowering embodied carbon, such as replacing ordinary Portland cement with supplementary cementitious materials (SCMs), typically slow down early strength development.”

This trade-off can cause costly delays on site as slower strength gain means formwork and scaffolding must remain in place longer. It also limits turnaround time in precast manufacturing, where production speed is key to profitability.

Chryso’s EnviroMix® range effectively resolves this challenge. Designed to support concrete mixes with high SCM content – such as fly ash or ground granulated blast furnace slag – EnviroMix® ensures that early strength targets are still reliably achieved. This allows for quicker demoulding, formwork removal and overall project momentum, without compromising sustainability goals.

“The economic impact of delayed early strength is significant,” Flannigan explains. “Whether it’s slowing down a construction schedule or reducing precast output, it affects profitability. EnviroMix® gives contractors and manufacturers the ability to keep to their deadlines while using greener materials.”

Backed by a strong global track record, Chryso’s low-carbon solutions were responsible for avoiding 15 million tonnes of CO₂ emissions in 2023 alone. The company’s laboratories also offer customised formulations, tailored to the variability of locally sourced SCMs, ensuring consistent results.

“With EnviroMix, sustainable concrete no longer means a compromise on productivity or quality,” says Flannigan. “It is a vital step toward greener construction – made practical, reliable and economically viable.”

An upward trend in the use of surface retarders in South Africa’s construction and infrastructure sector is shining a spotlight on the increasing popularity of exposed aggregate concrete finishes. According to Michelle Fick of Chryso Southern Africa, this trend reflects a growing appreciation for both the aesthetic and functional benefits that exposed aggregate offers.

“Exposed aggregate is no longer just a decorative finish; it’s being adopted across a wide range of applications from pavements and driveways to architectural facades and public infrastructure,” says Fick. “The textured non-slip surface offers a safer option for high traffic zones, while the natural stone aesthetic enhances the visual appeal of buildings and outdoor spaces.”

The finish is also ideal for preparing concrete surfaces that will receive a subsequent layer. Whether it is a waterproofing membrane, screed or cladding, the roughened texture created by the exposed aggregate allows for superior bonding, improving the durability and lifespan of the entire system. This makes it a preferred solution not only in aesthetic applications but also where structural performance is key.

Chryso Southern Africa offers surface retarders designed specifically to meet these evolving needs. The company’s products facilitate reliable consistent exposure of the aggregate to the required depth – up to a maximum of 3 mm – ensuring a uniform and high quality result. This is essential for specialist applicators who rely on precision and repeatability, particularly in large-scale or architecturally sensitive projects.

“The simplicity of the application process is another advantage,” Fick explains. “After the concrete is poured, the surface retarder must be applied evenly before the concrete begins to set. Following a predetermined curing period the surface is washed with water, removing the top layer of cement paste and revealing the aggregate below. A final sealant is then applied to enhance the surface’s durability and finish.”

Sealants can be selected to suit different environments and project need including internal and external use, UV resistance and finishes ranging from matte to high-gloss. This flexibility allows architects and contractors to customise the final appearance while ensuring long term performance.

Significantly, Chryso was the first manufacturer to offer a mineral solvent-free water-based retarder designed to prevent soil and groundwater pollution during the cleaning of treated concrete. The product contains no toxic substances, is 85% biodegradable, classified as harmless and complies with EEC Directives 88/379 and 93/18.

Fick notes that Chryso’s surface retarders are developed with the applicator in mind, offering not only technical consistency but also ease of use in site conditions that can often be challenging. “Our retarders provide reliable performance even under variable temperature and humidity conditions, which is critical for projects with tight timelines and complex environmental demands.”

With sustainability and safety continuing to drive specification choices in the built environment, the use of exposed aggregate finishes is expected to grow. “The combination of visual impact, surface durability, slip resistance and improved bonding makes it a smart choice for both new builds and renovations,” Fick concludes. “As the trend gains momentum, we are committed to supporting the market with reliable solutions that ensure consistent high quality results.”

As urban spaces evolve and developers seek more creative yet practical finishes, the role of surface retarders – and particularly exposed aggregate – is likely to become even more prominent in shaping the look and functionality of tomorrow’s concrete structures.

With growing demand for buildings that are not only functional but also visually striking, Chryso is helping customers reshape the face of concrete. Driven by technological advancements and a strong appreciation for architectural innovation, the company offers a broad portfolio of solutions that ensure concrete is both durable and beautiful.

According to Michelle Fick, Business Unit Development Manager for Concrete Aesthetics at Chryso Southern Africa, customers now have access to a wide range of innovative products tailored to various applications. “To achieve the desired aesthetic impact, it is essential to consider how the concrete is applied,” says Fick. “That is why we offer a comprehensive suite of solutions, including surface retarders, integral pigments, surface treatments, curing compounds and demoulding oils.”

These products can be used in combination to enhance even the most basic concrete features such as pillars or floors, ensuring that aesthetics are never overlooked, regardless of the project’s scale or complexity. 

One of the most common requirements in aesthetic concrete applications is colour consistency. Chryso’s integral iron oxide pigments provide vibrant durable colour throughout the concrete mass – so even chips or abrasions won’t reveal an underlying colour difference.

Surface quality is another priority. Chryso’s plasticisers and superplasticisers improve the workability and flow of the concrete mix, reducing surface defects and ensuring a smooth high quality finish. To further strengthen and enhance surface performance, the company also offers densifiers and hardeners that provide improved abrasion resistance. Additionally, its release agents support a clean separation from formwork, enabling a high class finish with consistent colour and texture.

Texture also plays a vital role in the visual appeal of concrete. Viscosity modifying admixtures like CHRYSO® Quad 20 improve cohesion, preventing issues such as segregation or honeycombing. 

Efflorescence – the white powdery residue that can appear on concrete surfaces – is a common challenge that Chryso tackles with products like CHRYSO® Fuge B, an integral waterproofing admixture that blocks pores and reduces the risk of moisture ingress. The company also offers water-repellent surface treatments, such as dry-coat sealers, which prevent water from reacting with free lime  – the cause of efflorescence.

Surface finishing is key to consistency, and CHRYSO® FiniSafe can be applied just before the final finishing operation to enhance surface uniformity. Fick stresses that the success of any aesthetic concrete application depends on best practice. “Consistent batch control, quality materials and correct curing techniques are essential,” she says. “We always recommend proper concrete trials before commencing a project, especially for large-scale applications, to confirm the best combination of admixtures and placement methods.”

Chryso takes a collaborative approach, working closely with customers from planning to execution to ensure outstanding aesthetic outcomes. “Our innovations are designed to make concrete beautiful,” concludes Fick. “But it is our hands-on support that helps customers unlock their full creative and architectural potential.”

As Africa’s construction industry embraces greener practices in meeting its infrastructure needs, CHRYSO is on board with a rebranded focus on sustainability. 

Having merged with GCP Applied Technologies under the Saint-Gobain banner, Chryso’s new identity reflects its commitment to eco-friendly innovation, according to Sibu Hlatshwayo, Managing Director of Chryso Southern Africa. This focus is at the core of its mission to responsibly support Africa’s infrastructure growth.

“We are addressing local needs while helping customers reduce CO₂ emissions,” says Hlatshwayo. “Our new green branded identity signals our dedication to pioneering the future of construction by creating practical, sustainable solutions.”

He highlights that Chryso’s approach centres around four pillars: innovation, proximity, partnership and sustainability. An example of its innovative edge is the Chryso® Quad Range, which allows contractors to use local aggregates that fall below traditional standards, to minimise transport distances and reduce carbon emissions. 

“Our Chryso Quad app complements our technical capability, guiding users to the best products based on specific aggregate characteristics, while our clay testing kit helps ensure quality results,” he explains. “Our Chryso EnviroAdd Range further reduces the environmental impact of construction by lowering clinker content in concrete mixes, as clinker is one of cement’s most energy-intensive components.”

Another breakthrough is Chryso’s innovations related to limestone calcined clay cement (LC3), a more sustainable alternative to traditional cement that blends limestone and clay to produce a greener concrete.

“Proximity is also a critical aspect of CHRYSO’s strategy, as we consider ourselves as a ‘multi-local’ business – rather than just multinational,” he says. “Our African footprint is well equipped to meet specific local needs with our facilities and our sales and technical support teams. By expanding our network of local laboratories – recently opening a new facility in Kenya, for instance – we can test raw materials locally and quickly to provide optimised solutions.”

Through more localised production, such as its manufacture of cement additives in Ghana, customers have the advantage of quicker turnaround times and reduced logistics costs, as well as the convenience of purchasing in local currency. 

“CHRYSO is also driven by a passion for collaboration,” says Hlatshwayo. “Climate change requires a united approach, so we work with partners across the construction ecosystem to enhance our impact.”

Sustainability is at the heart of Chryso’s mission, and the company shares both admixture solutions and specialised knowledge to help customers to reduce their environmental footprint. The Chryso Academy is a valuable resource in this mission, offering courses to contractors, universities and other stakeholders to promote sustainable construction.

He concludes that sustainability needs to include renewed attention on the circular economy, as Africa’s rapid urbanisation is demanding increased recycling of concrete. This is another area where Chryso admixtures are playing their role. 

Concrete performance and durability underpin the value to society of water-retaining structures such as water treatment plants and storage reservoirs – and admixtures make all the difference.

Challenges, including cracking and permeability, can undermine the strength and longevity of these structures, according to Michelle Fick of CHRYSO Southern Africa’s Concrete Aesthetics Business Unit.

“Cracking of concrete, for instance, often calls for urgent and costly maintenance of water-related infrastructure,” says Fick. “In addition to leakage, cracks can undermine the strength of a structure due to corrosion of the steel reinforcing.”

She highlights the importance of reducing shrinkage in concrete to avoid cracking, using admixtures such as CHRYSO® Serenis. By reducing the volume changes that occur during the curing process, this admixture helps to prevent cracking. It works by decreasing capillary tension, protecting concrete against moisture transmission, chemical attack and corrosion of reinforcing steel.

There are also waterproofing agents, like pore blockers such as CHRYSO® Fuge B that further enhance concrete’s resilience against chemical attack and reduce permeability, she adds. 

“Another waterproofing agent is crystalline admixture such as CHRYSO® CWA 10,” she says. “This reacts with moisture to form crystals deep within the pores and capillary tract of the concrete structure.”

Admixtures such as plasticisers and super plasticisers are critical in ensuring workability of concrete, which is especially vital to heavily reinforced structures like reservoirs, adds Patrick Flannigan, Technical Manager of the Concrete Business Unit at CHRYSO Southern Africa. 

“Water in the concrete mixture must be kept to a minimum to ensure strength and density, which could hamper its workability,” says Flannigan. “However, admixtures allow the concrete to continue to flow into the cavities between the steel reinforcing, which is often extensive to ensure strength in these large water-related structures. Secondary reinforcing can be achieved through the application of macro-fibres and micro-fibres, which can reduce the amount of steel while also further reducing the risk of cracking.”

Another aspect of water-retaining structures to consider is their weight, so the ground underneath them must be well drained if they are to remain stable. “To ensure water does not collect, a pervious base layer usually needs to be installed,” he says. “This is constructed from no-fines concrete, which allows water to flow away without eroding the sub-base material.”

He notes that an admixture like CHRYSO® Easy Drain is ideal for no-fines concrete, as it coats the coarse aggregate to ensure a stronger bond between these particles and the cement-water mix.

In today’s construction industry, the twin imperatives of sustainability and efficiency are driving transformative innovations. One such advancement making waves is the use of fibre in concrete, replacing traditional steel reinforcement. This shift not only results in substantial time and labour savings leading to significant cost efficiencies, but also plays a pivotal role in reducing the carbon footprint associated with construction projects.

Steel reinforcement, while indispensable for its strength and durability, exacts a heavy toll on the environment. The production of steel involves substantial energy consumption and emits significant amounts of carbon dioxide (CO2). According to the World Steel Association, the steel industry accounts for approximately 8% of global CO2 emissions, making it a prominent contributor to climate change.

Michelle Fick, BU Development Manager: Concrete Aesthetics at CHRYSO Southern Africa, says that fibres, in contrast, are made from synthetic and natural materials and offer a far more sustainable alternative. Concrete containing fibres is thus easily recycled for reuse as crushed aggregates for other projects. 

The environmental benefits of this shift are significant. The production of fibre materials, particularly synthetic ones, generates considerably less CO2 compared to steel production. Additionally, the energy requirements for manufacturing fibres are significantly lower. 

“By substituting steel with fibres, construction companies can markedly decrease their carbon emissions,” Fick says. “Further unlike steel reinforcement, which often involves cutting and fitting, leading to substantial scrap material which needs to be managed, our Advil fibres can be precisely mixed into concrete, minimising waste on construction sites. This reduction in waste contributes further to the sustainability credentials of fibre-reinforced concrete.”

Beyond the environmental advantages, fibre reinforced concrete offers several practical benefits that enhance construction efficiency. Integrating fibres into concrete is straightforward and can be done during mixing, eliminating the labour-intensive steps of placing and tying steel reinforcement. 

This streamlined process significantly accelerates construction timelines. The simplicity of using fibres reduces the need for specialised labour typically required for handling and installing steel reinforcement. This not only cuts down on labour costs but also mitigates the risk of on-site injuries associated with traditional steel handling. 

Fick says that while the initial cost of fibres may be close to that of traditional steel reinforcement, the overall savings in labour, time and reduced waste translate into lower total project costs over the lifecycle of the construction project.

Fibre-reinforced concrete has been successfully deployed in numerous projects globally as well as locally, highlighting both its practical and environmental benefits. Infrastructure projects like roadways and bridges have reported enhanced durability and reduced maintenance costs due to the use of fibres. 

Moreover, residential and commercial buildings have benefited from faster construction times and improved structural performance, highlighting the versatility and effectiveness of fibre-reinforced concrete across diverse applications.

Available from CHRYSO, Adfil’s range of high quality fibre reinforcement solutions are designed to enhance the performance of concrete by improving its durability, reducing cracking and increasing its structural integrity. By integrating Adfil fibres into concrete, construction projects can achieve superior results while also benefiting from the environmental advantages of reduced carbon emissions and lower energy consumption.

Adfil offers a range of fibres tailored to various construction needs including macro-synthetic fibres, micro-synthetic fibres and steel fibres. These products are engineered to provide optimal reinforcement, ensuring that concrete structures can withstand the demands of modern construction without the drawbacks associated with traditional steel reinforcement.

“We believe that the adoption of fibre in concrete represents a paradigm shift in the construction industry, and offers contractors  a sustainable and efficient alternative to traditional steel reinforcement,” Fick says. “By reducing carbon emissions, minimising energy consumption and cutting down on waste, construction companies can significantly lessen their environmental impact while bolstering their operational efficiencies.”

“As the construction sector continues to prioritise sustainability, embracing innovative materials like fibre will be pivotal in fostering a greener future. These advancements not only align with global environmental goals but also position construction companies at the forefront of sustainable practices, driving both environmental stewardship and economic viability,” Fick concludes. 

With the construction sector in East Africa seeing an upswing, CHRYSO East Africa has grown its offerings to the market while ensuring its admixture solutions are targeted at local conditions.

According to Graham Dean, CHRYSO’s Business Development Director Eastern Africa, the region’s growing investment in construction projects is evident in countries like Kenya, Tanzania and Uganda. While infrastructure development such as roads and railways are mainly driving this growth in Kenya, it is Tanzania’s mining industry and Uganda’s oil sector which are becoming more significant.

“As a key construction product, concrete uses natural materials which are locally sourced,” says Dean. “This might include cement produced from limestone quarried around Nairobi, pozzolana to modify different cement types or quarried aggregates and crushed sands. To achieve the best results in concrete, it is important to understand the variations in what Mother Nature provides to us as raw materials.”

He highlights that concrete admixtures which have been well proven with materials in South Africa, for instance, may not necessarily perform to the same levels with concrete materials from Kenya. Accommodating these variations has required considerable investment in research and technical facilities in East Africa, to ensure customised admixture solutions.

“To resolve the performance differences between regions, CHRYSO set up a concrete laboratory in Nairobi where we can modify existing formulations,” he explains. “This allows us to design bespoke admixtures for customers, based on their specific requirements and the local materials going into their concrete.”

With its Nairobi office established almost 10 years ago, CHRYSO has developed the locally based experience and infrastructure to become a trusted partner in the concrete space. The company supplies its admixture solutions not only to large construction companies, specifiers and developers, but also to readymix plants, manufacturers of precast products and specialist applicators of decorative concrete.

As the negative environmental impact of sand mining falls under the spotlight in certain East African countries, CHRYSO is also contributing to more responsible practices in the concrete segment.

“The uncontrolled mining of river sand for concrete in many areas has led to concerns at government level, and an expectation that this practice might be banned in future to prevent further damage to the natural environment,” says Dean. “We have promoted our Quad range to raise awareness in the construction industry about alternatives to river sand.”

CHRYSO uses its in-house polymers in the Quad range of products to accommodate the use of challenging sands, including too little or too much fines, swelling clays or irregular shapes. Being able to use lower quality sands can drive down procurement costs, and can also reduce the carbon footprint of a given concrete where these alternative materials are closer to site.

“We have also taken a leading role in the supply of additives to cement producers, with our in-depth understanding of cement production technologies,” says Dean. CHRYSO has been supporting cement producers to reach their sustainability goals, as cement manufacture is a leading contributor to carbon dioxide emissions. The company’s innovations allow more efficient clinker grinding, reducing power consumption in this energy intensive process. 

The additives permit increases in the compressive strength at the initial, mid-term and later ages. The resulting enhanced performance can meet specific market needs such as reducing cement fineness or lowering unit production costs. The clinker factor can also be reduced by using increased levels of supplementary cementitious material (SCMs) while retaining cement performance. CHRYSO additives can be used for the grinding of most cements in all types of grinding systems, including those with ball mills, roll presses, and open and closed circuits, as well as horizontal roller and vertical roller mills.

CHRYSO is able to develop specialised products for customers, to suit their applications. A customer in Mombasa, for instance, needed a solution for the use of coral limestone as a bulking agent in cement production.

“Coral limestone is a notoriously difficult material to blend effectively into cement,” he notes. “Through extensive trials for the customer, CHRYSO East Africa was able to formulate a solution by finetuning one of our products; the result was a solution which overcame the customer’s challenge and is now being regularly used.”

With South Africa’s winter season on its way, many concrete users will know that slower curing times could derail their contract or production schedules, but accelerating admixtures – or accelerators – are available to solve this challenge.

With the country’s generally temperate climate, it is easy to forget that many provinces and neighbouring Lesotho regularly experience sub-zero temperatures, points out Hannes Engelbrecht, Concrete Business Unit Director for Domestic and Sub Saharan Africa (SSA) at CHRYSO Southern Africa. Temperatures do not even need to reach freezing point; the concrete hydration process slows down steadily as temperature drops and actually stops when it goes below about 5 degrees Celsius.

A significant amount of current concrete construction – especially for wind turbine bases and foundations for solar photovoltaic infrastructure – is, in fact, taking place in provinces like the Northern Cape and Eastern Cape where temperatures fluctuate widely. Efficient stripping time of formwork is crucial in allowing these projects to meet their stringent deadlines to complete construction and start delivering renewable energy.

“Low temperatures create a range of problems for contractors and concrete product manufacturers,” says Engelbrecht. “Most projects in today’s world need to be delivered on a fast track basis, so there is no room for slow concrete curing to hold up the schedule. Similar constraints apply in the manufacture of precast products, where production must simply keep up with customer orders and delivery deadlines.”

He highlights that precast product manufacturers can use a combination of super plasticisers and accelerators to speed up their stripping times and reduce the storage space needed for products to cure. Accelerators work during the first 18 hours of the concrete’s curing time to ensure efficient hydration required to depalletize. Should temperatures be lower than freezing point, this makes the concrete strong enough to resist the expansion of water as it freezes – so that the concrete will not crack.

Patrick Flannigan, Technical Manager of the Concrete Business Unit at CHRYSO Southern Africa, explains that there are two categories of accelerator – chloride and non-chloride. While chloride-based accelerators are usually the first choice, they cannot be used if there is steel in the structure or where steel reinforcing is present due to the risk of rust, corrosion and degradation.

“If there is steel reinforcing in the concrete, then a non-chloride accelerator must be selected,” says Flannigan.

Regarding the use of accelerators in readymix concrete that must travel varying distances to site, he points out the accelerator is best applied once the readymix has arrived on the customer’s site. After it is added to the concrete in the mixing truck, it needs to be thoroughly mixed for 5 to 10 minutes before being poured. The admixture gives operators a good 30 to 40 minutes of workability before the accelerated hydration begins, depending on the type of concrete mix.

Another growing benefit of accelerators has emerged as a result of the global sustainability drive, he says, as cement producers, contractors and other customers aim to reduce their carbon footprint. This trend has seen the increased use of extenders such as fly ash and granulated slag in cement.

“The fly ash and slag only start working once there is an initial hydration of cement,” he says. “This means that the early strength of a concrete mix will be delayed when there are extenders added.”

The accelerating admixture overcomes this initial delay in the early setting, allowing users to achieve their sustainability goals without compromising on speed of the curing process.

In recent years, the mining industry in South Africa has become a major user of fibre-reinforced shotcrete for underground support. In line with this trend, CHRYSO Southern Africa reports growing demand for its market-leading CHRYSO® CSF 6000 high performance macro-synthetic fibres.  

Fall of ground (FOG) – one of the leading causes of injuries and fatalities in underground mines – remains one of the biggest obstacles to the industry’s quest for Zero Harm in South Africa. The fight to eliminate FOG incidents is therefore one of the main reasons for the escalating use of fibre reinforcement in shotcrete, says Willie Nel, Technical Sales Consultant at CHRYSO Southern Africa. 

Having traditionally used reinforced shotcrete with wire mesh or welded mesh, the industry then moved over to fibres. These were initially steel fibres and then rigid polypropylene ‘broombrissel’ fibres took centre stage. However, the past decade has seen an accelerated switch to polypropylene homo-polymer fibres – a soft tape fibre. 

“The move to soft tape fibres gained traction from around 2012,” explains Nel. “During that period, we have experienced growing demand for our CHRYSO® CSF 6000 high performance macro-synthetic fibres which are specifically designed to satisfy the demanding requirements for modern day shotcrete reinforcement technology. In our experience, the trend is largely being driven by new mining projects.”

A major advantage of the CHRYSO® CSF 6000 is its flat, flexible nature which leads to better tensile strength than, for example, the rigid ‘broombrissel’ counterparts. In addition, it combats the formation of plastic shrinkage and plastic settlement cracking, while still providing high impact-, abrasion- and shatter-resistance. The technology, adds Nel, boasts greater ductility, which allows it to deform under tensile stress, as well as enables greater energy absorption. 

This was proven at one of the biggest copper mines in South Africa, where the client stipulated a 45 MPa shotcrete mix design. CHRYSO Southern Africa went on to achieve over 1000 joules of energy absorption by using the CHRYSO® CSF 6000 macro-synthetic fibres.

“Traditional reinforcement practices such as wire mesh and welded mesh are not conducive to high productivity and are costly due to the labour intensive process of mesh installation. In contrast, macro-synthetic fibre-reinforced shotcrete is a system capable of supporting rapid application and semi-automation,” concludes Nel.