Tag Archives: Chryso Southern Africa

WHEN HEAT OR COLD COMPLICATES CONCRETE – CALL CHRYSO

When ambient temperatures become very hot or cold, concrete users can struggle to achieve the required strength and workability – but there are admixtures for those challenges.

Patrick Flannigan, Technical Manager at CHRYSO Southern Africa, explains that high temperatures cause concrete to develop higher initial strength, but reduce the strength development over the long term. Very cold weather creates the opposite effect, causing lower strength gain initially but higher strength gain later.

When temperatures drop below 5°C, the slower hydration process could even cause extended bleeding. At temperatures lower than that, there is a risk that the water in the concrete will freeze. Water expands by 9% when it freezes, so it could even cause cracking if the concrete has not reached sufficient strength.

“To deal with very hot weather, customers use our CHRYSO® Tard range of plasticisers, which ensures enough open time,” he says. “This retarder slows down the hydration of cement by momentarily blocking the surface of the cement particles and delaying the time of initial setting.”

For cold weather, he recommends the CHRYSO® XEL range of chloride and non-chloride accelerators, which help with early strength gain of concrete. To deal with the risk of water freezing in the concrete, CHRYSO® Air helps by adding extra air to the mix. Instead of cracking the concrete, the freezing water will expand into the capillary openings that the air entrainer has created. These low temperatures are not that common in South Africa, but more relevant to higher elevated areas such as the Lesotho Highlands.

“Another form of extreme weather leading to challenges with concrete is heavy rainfall that causes flooding,” he says. “Protection of concrete in rainy conditions is of the utmost importance, as this will eliminate surface blemishes on exposed concrete areas.”

Flannigan explains that concrete that is in contact with standing or flowing water needs to be protected, especially in terms of its finish. “CHRYSO® Aquabeton is the ideal solution for concrete that needs to be placed underwater, and this allows concrete to be cast in standing or flowing water.”

Flannigan points out that CHRYSO’s solutions are driven not only by functionality but by a global commitment to sustainability. The company develops admixtures specially for certain types of cement and construction material. This allows a wider range of material to be sourced close to site, even if it is high in clay content, for example.

“This reduces the distances that material needs to be transported and therefore keeps vehicle carbon emissions to a minimum,” he says.

LOCAL ADMIXTURE, POLYMER FACILITIES PUT CHRYSO AT LEADING EDGE

Having set up its South African offices and admixture manufacturing facility in Jet Park near Johannesburg in 2005, CHRYSO Southern Africa has developed extensive local capability to serve markets in the region.

CHRYSO Southern Africa has manufacturing plants in Jet Park, Cape Town and Durban, as well as warehouses in Gqeberha and Bloemfontein. While the facilities in Cape Town and Durban produce about 70% of their requirements, there are certain specialised products that are supplied to them out of the Jet Park operation.

Among the company’s forward-looking infrastructure is its polymer production facility, which began operating in 2015. It produces four polymers for the manufacture of plasticisers and superplasticisers that are used in concrete mixes. It also has the capacity to produce four more different polymers, according to Andries Marais, Operations Director at CHRYSO Southern Africa.

“We were the first Southern Hemisphere company in the CHRYSO group to manufacture these specific polymers,” says Marais. “We used to import them from the group’s facility in France, when we would bring in around 38 containers every month; now we are able to import the raw materials and require only one container of specialised product each month.”

He highlights that having the polymer plant in South Africa has reduced logistical costs substantially, allowing savings to be passed on to the customer. It also allows much more flexibility in the manufacturing process. These polymers can be combined in any ratio required by customers to suit specific site conditions – addressing vital factors like workability and water demand.

“Every project location will have different environmental conditions, different construction materials and even different cement – so the concrete is not going to perform in the same way,” he explains. “With the production flexibility with our polymers, we can locally customise the solutions for each specific requirement, which really benefits our customers.”

The local facilities give CHRYSO Southern Africa the ability to make immediate changes to its admixture ingredients by varying the proportion of the different polymers – which are readily available in their plants. So responsive is this system that the company can have the necessary product ready for the customer within 24 to 48 hours. 

“If you are reliant on imported polymers, it takes three months to import the necessary stock,” he says. “Then, if a customer’s cement chemistry changes, you might not have the required polymers to make the necessary adjustments to the admixture.”

Keeping the plants up to date and efficient takes continuous investment, emphasises Marais. CHRYSO South African reinvests 3 to 5% of its annual turnover into the facilities, to allow for regular strategic upgrades. For example, the mixer at the Jet Park plant is being upgraded at a significant cost, specifically to support the needs of the mining sector – a project that he expects to complete by the end of 2023. This was done in response to approaching 100% of the current capacity for a specific mining product. 

“As we expand into Africa, we see considerable opportunity for growth in the mining industry – and so we need extra capacity to meet this expected demand,” he says. CHYRSO Southern Africa has been moving into various new countries since 2010. Markets in Zimbabwe, Botswana, Mozambique, Namibia and Zambia are already being serviced, and an office and toll manufacturing facility has been opened in Kenya.

The investment in the polymer plant alone has been doubled in the past three years, he points out, to increase its efficiencies and to grow its capacity by 100%. This will also allow the company to export polymers to Latin America in 2024, where the necessary formulations can be manufactured. He highlights how CHRYSO Southern Africa’s local facilities have opened up opportunities for businesses in the construction and other sectors. 

“We have created the volumes and cost effectiveness to allow producers of concrete products to thrive,” he says. “We also nurture skills by employing post-graduates in our Jet Park plant, as well as to develop our research and development capacity to investigate formulations. We rely on concrete technologists in developing the products themselves.”

The manufacturing process is conducted at atmospheric pressure and below 80 degrees Celsius, which assists in addressing efforts by CHRYSO Southern Africa and its customers to reduce their carbon emissions. Marais says that the company has been monitoring its carbon footprint in recent years and is committed to steadily reducing this factor to 50% of current levels by 2030.

Quality is also a key consideration in all three plants countrywide, where the ISO 9001 quality management system is rigorously applied. He adds that the same attention is paid to environmental management through ISO 14001, and to safety through ISO 45001.

CHRYSO SOUTHERN AFRICA’S LEADING-EDGE LABORATORIES PROPEL INNOVATION AND QUALITY ASSURANCE

CHRYSO Southern Africa, located in Jet Park, Johannesburg, maintains two state-of-the-art laboratories that form the backbone of its operations. These facilities, the Quality Control and Research and Development Laboratory and the Concrete and Cement Laboratory, support the company’s customer across all industries by ensuring quality, safety and efficiency.

Mpumi Mlalazi, R&D Manager at CHRYSO Southern Africa, explains that the Quality Control and Research and Development Laboratory has a multifaceted role. “Firstly, it ensures quality assurance and compliance with industry standards and by doing so, strengthens our reputation of reliability and trust.”

“By driving process improvement initiatives, we enhance our efficiency and effectiveness and through this our laboratory plays a crucial role in facilitating innovation and new product development, ensuring we stay at the forefront of industry advancement,” Mlalazi says. “The laboratory also offers problem-solving expertise to our customers, ensuring issues are quickly identified and rectified, adding value to their bottom line.” 

The Concrete and Cement Laboratory also has several functions. It conducts comprehensive material testing and analysis, ensuring the quality of cement and concrete chemicals used in industry. Mlalazi explains that by evaluating strength and durability properties, CHRYSO Southern Africa ensures that the materials used can withstand the demanding conditions of the particular application where these materials are being used. 

“Our team also performs chemical analysis for compliance and optimal performance, and the laboratory engages in research and development for new chemicals and formulations. We also explore specialised applications and sustainability considerations, and doing this ensures our operations remain environmentally conscious,” she says. 

By harnessing the capabilities of these laboratories, CHRYSO Southern Africa reaffirms its commitment to delivering a customer focused service, meeting the highest quality standards and addressing the specific needs of its customers in Africa. 

Mlalazi affirms that the CHRYSO laboratories undergo annual audits to maintain its ISO certifications, further demonstrating commitment to quality, environmental responsibility and safety. “Our ISO 9001 certification is a testament to the emphasis we place on quality management principles such as customer focus, the involvement of top management, a process-driven approach and continuous improvement. Our ISO14001 certification emphasises our dedication to measuring and actively improving our environmental impact, demonstrating to company management, employees and external stakeholders our commitment to environmental responsibility.”

CHRYSO ECO DUST MINIMISES DUST EMISSIONS

An innovative range of dust suppressants available from CHRYSO Southern Africa, continues to be a gamechanger in the mining and quarrying sectors, providing substantial benefits and enhancing operational efficiency.

Sealing a road with CHRYSO Eco Dust.
Sealing a road with CHRYSO Eco Dust.

CHRYSO Eco Dust has a proven track record as an indispensable tool for industries operating in dusty environments. Michelle Fick, BU Development Manager: Concrete Aesthetics and Key Accounts, at CHRYSO Southern Africa, says this range of dust suppressants offers a comprehensive approach to sealing and maintaining dirt roads, gravel pathways, and other dusty surfaces.

“One of the major advantages of CHRYSO Eco Dust is its cost effectiveness,” Fick says. “Compared to alternatives such as paving or tarred roads, implementing the CHRYSO Eco Dust solution leads to significant cost savings. This is particularly important for operations facing challenging economic times as there is immense value in reducing maintenance expenses while achieving optimal dust control.”

She explains that CHRYSO Eco Dust provides long lasting effects, ensuring that roads and surfaces remain dust-free for extended periods. This characteristic is crucial in industries where regular maintenance and constant dust suppression efforts are time consuming and costly. By reducing the frequency of reapplication, CHRYSO Eco Dust streamlines operations and minimises disruption to daily activities.

Another major advantage offered by CHRYSO Eco Dust is its eco-friendly nature. The product is designed to be environmentally sustainable, with low volatile organic compound (VOC) emissions and UV resistance. Industries, especially those subject to stringent health, safety, and environmental regulations, have welcomed CHRYSO Eco Dust as a viable solution to ensure compliance while minimising their ecological footprint.

Fick is quick to point out that CHRYSO Eco Dust has gained traction in mining and quarrying operations. “These industries, which are often located in environmentally sensitive areas, face increasing pressure to minimise dust emissions and their impact on surrounding communities. CHRYSO Eco Dust not only helps meet regulatory requirements but also significantly reduces fuel and water consumption and carbon dioxide emissions associated with traditional dust control methods, such as water tanker spraying. The result is a greener and more sustainable approach to dust suppression.”

Moreover, CHRYSO Eco Dust improves overall safety in dusty environments. By minimising dust particles in the air, visibility is enhanced thereby reducing the risk of accidents. The improved road gripping also enhances traction for vehicles, further contributing to safety and preventing potential mishaps.

CHRYSO Southern Africa’s commitment to providing a comprehensive solution extends beyond mining and quarrying. The versatile applications of CHRYSO Eco Dust have made it a preferred choice in cement plants, precast yards, building sites, farms, game reserves, rural airfields and other areas where dirt roads and dusty surfaces require sealing and maintenance. Even less developed residential areas and sandy football pitches can benefit from the long lasting effects of CHRYSO Eco Dust.

QUAD RANGE FROM CHRYSO UNDERPINS COMMITMENT TO SUSTAINABILITY

Once again, CHRYSO is the first out of the starting blocks, having introduced its CHRYSO® Quad range of concrete admixtures to the market in 2022 – helping customers to promote sustainable practice in their use of challenging sands.

According to Patrick Flannigan, Technical Manager in the Concrete Business Unit at CHRYSO Southern Africa, the use of crusher or manufactured sand in construction has been prevalent for many years as it is a cost effective and more readily available alternative to natural sand.

“There have, however, been issues with grading which often prompts contractors to supplement with natural sand from sources such as rivers and dunes,” he explains. “This is where the challenges lies with less availability of natural sands which increases costs as well as the presence of clays which means that less of this material can be used or it has to be excluded completely.”

“Our CHRYSO® Quad range allows customers to reduce their use of natural sand while making better use of crusher sand, without compromising the quality of their concrete mixes, and successful laboratory trials have already been concluded with customers in various market segments are already realising the benefits,” Flannigan continues.

Patrick Flannigan, Technical Manager in the Concrete Business Unit at CHRYSO Southern Africa.
Patrick Flannigan, Technical Manager in the Concrete Business Unit at CHRYSO Southern Africa.

“Working with customers such as contractors, readymix suppliers and precast manufacturers, CHRYSO is making significant contributions to industry sustainability and reduced carbon footprint,” he says.

He highlights that using less natural sand gives the industry a lower environmental impact on sources like rivers. Where natural sand is still being used, CHRYSO® Quad CLEAR® (Clay Enabling Admixture Response) allows a wider choice of sources – even challenging sand that contains swelling clay. This can allow contractors to source from locations closer to site, reducing the carbon footprint and cost of transporting sand over a long distance.

“The challenge is that swelling clays absorb newer generation plasticisers, thereby preventing them from delivering benefits such as water reduction or slump retention,” he says.

CHRYSO Southern Africa also offers the quick and innovative CHRYSO® CLEAR Test to identify where these swelling clays could present a problem for concrete users. Where they are identified in the source material, CHRYSO® Quad CLEAR® can be added as a liquid to the relevant plasticiser.

Another important contribution to sustainability in the construction and concrete manufacturing sectors is CHRYSO® Quad GRAFT® (Gap Gradation Fixing Technology), he notes. This can solve the challenge of an excess or lack of fines in source material – which often occurs in crusher sand.

“The industry is seeing the environmental benefit of moving away from natural sand and more toward crusher sand, but this product often has varying levels of fines,” he says. “In the past, this could have compromised the performance of concrete, but CHRYSO® Quad GRAFT® now solves this challenge.”

Because sands are unique, CHRYSO offers tailor-made solutions for both excess and lack of fines.
Because sands are unique, CHRYSO offers tailor-made solutions for both excess and lack of fines.

KARIBA DAM PROJECT FORGES AHEAD WITH CHRYSO ADMIXTURES

Contractors are getting closer to the key objective of the Kariba Dam Rehabilitation Project – to reshape the plunge pool below the dam wall and arrest any further erosion.

Concrete is a central element of this world class engineering project, and CHRYSO® Southern Africa’s Zambian distributor, Mart Solutions Ltd has been one of the key suppliers of construction chemicals to main contractor Razel-Bec since the very beginning of the project. This collaborative effort over the past several years has ensured the project’s steady progress. With the aim of stabilising the plunge pool at the foot of the 138 m high dam wall, the project is using vast quantities of concrete in a range of applications.

The total volume of concrete used – which includes the coffer dam and underwater works as well as excavation – is almost 26 500 m3. At the coal face is Mart Solutions Director, Martie Coulson.

Kariba Dam before piers and after all piers in place.
Kariba Dam before piers and after all piers in place.

“Among the first challenges we faced was in the construction of piers for the temporary coffer dam, where concrete had to be poured underwater to create a foundation,” says Coulson. “Difficulties in finding bedrock for piers 7, 8 and 9 – as well as for the dam’s right bank – meant that 22,000 m3 of concrete had to be placed underwater.”

This arduous process – which took six months and was completed in September last year – involved pumping concrete to 25 m deep, with divers handling the 125 mm diameter pipe to place the concrete. Adding to the complexity was the movement of water from the nearby Zimbabwe’s hydro-electric turbine outlet, which exacerbated the ‘wash’ off the concrete into the surrounding water.

“This raised the risk of the cement being washed out of the mix, leaving the aggregate behind as well as further reducing visibility for the divers,” she explains. “The CHRYSO® Aquabeton product played a critical role as an anti-washout admixture that increases the cohesion of the concrete mix.”

This allowed the placement of a concrete base for the three piers, measuring some 15 m wide and 20 m deep. Another important aspect of the project is repairing a fault in the rock at the foot of the Kariba dam wall. Stitching of the fault will include the use of 40 mm anchors in the rock with CHRYSO NS Grout added to a concrete mix. In addition, 20 mm, 25 mm and 32 mm anchors will be used and will be secured with a.b.e.® dura.grout supplied by Mart Solutions Ltd.

First pier to be floated into place on 18 January 2021.
First pier to be floated into place on 18 January 2021.

“Some 7 071 m3 of specialised concrete will be used for the large 90 m high, 45 m wide and 2,5 m thick wall which will be built in front of the fault as a protective shield,” she says. “This will be fixed onto the 12 m long, 40 mmdiameter anchors in the wall, which will in turn be secured 10 m into the rock.”

A combination of CHRYSO® Omega 162 and CHRYSO® Fluid Optima 206 will be used in conjunction with densified silica fume and fly ash in the concrete mix for the wall – to assist in preventing the temperature rise in the concrete during  placement and to avoid cracking. This is important due to the high ambient temperatures of up to 40 degrees Celsius.

“We have been running laboratory trials for three years to ensure that the concrete mix design will meet the standards specified by the engineers for the wall to ensure that the concrete will remain below 55 degrees Celsius during placement,” she explains.

As part of the preparation of the concrete, therefore, a chiller plant will be cooling the water and aggregate before it is added to the mix. In another aspect of the project, Mart Solutions is providing the anchors to secure the safety nets which are being installed against the risk of rockfalls in the excavation, as well as a.b.e.® dura.grout for securing the anchors. This non-shrink cementitious grout quickly develops placeable consistency and remains cohesive. CHRYSO Jet 30 is also being supplied for shotcreting, mixing with concrete as it is sprayed to ensure adhesion to the rock surface.

Section of underwater concrete that was placed as bedrock was not found.
Section of underwater concrete that was placed as bedrock was not found.

“As the coffer dam is dewatered, the contractors are able to start micro-blasting to clear rock from the plunge pool,” she says. “The walls must then be secured to prevent any rocks from falling.”

Mart Solutions has already provided the CHRYSO® Omega 162 superplasticer for building the coffer dam piers. Ranging from 250 tonnes to 700 tonnes in weight, these piers measure 5,5 metres tall.

“The new generation CHRYSO® Omega 162 high range water reducing plasticiser played an important roleto reduce water demand, thereby increasing the concrete’s durability,” she says. “It also improved the concrete’s cohesion and lowered its viscosity, for better homogeneity and off-shutter finish.”

CHRYSO® Omega 162 allows concrete to exhibit extended workability characteristics, while CHRYSO® Fuge B – a pore-blocking permeability reducer for mass concrete – was used in the coffer dampiers to prevent the penetration of water under pressure.