Tag Archives: Chryso Southern Africa

CHRYSO GROWS ITS LABS TO PUSH CEMENT TECHNOLOGY

In its quest to help customers generate more sustainable construction materials, CHRYSO Southern Africa has continued to enhance its laboratory facilities – even during the disrupted years following the onset of the Covid-19 pandemic.

The latest expansion within its Centre of Excellence in Jet Park near Johannesburg has been a cement laboratory, in which the company has invested extensively. According to research and development (R&D) manager Mpume Mlalazi, these investments will continue into 2022 to ensure the latest tools are available.

“Much of our work in the cement laboratory is focused on the growing global concern to reduce carbon dioxide emissions from cement manufacturing,” says Mlalazi. “We are also now fully equipped to align with international standards in cement testing.”

CHRYSO Southern Africa’s other facilities include a research and development laboratory for new product formulation and evaluation, a concrete laboratory conducting physical tests to evaluate concrete properties, a quality control laboratory and a colour laboratory.

There are also satellite laboratories at the company’s Cape Town, Port Elizabeth and Kwa-Zulu Natal branches to support customers. Amongst the equipment recently acquired is an isothermal calorimetry and permeability tool; in addition to basic tools for cement setting time, specific surface Blaine, pycnometry and cement compressive strength determination auxiliary equipment.

“Our cement laboratory works closely with cement industry players, and supports our customers with product development to find solutions for their ever-changing applications,” she says. “Of course, cement is the main contributor to concrete performance, so it is vital that we understand exactly what impacts are achieved by the changes we can make.”

This is why CHRYSO Southern Africa’s wide breadth of facilities – combined with its depth of expertise – is so effective, with its cement and concrete laboratories under one roof, she explains. Whatever is achieved in the cement laboratory can be closely assessed and tested in the concrete laboratory.

“As experts in the field of admixtures, we have the necessary chemistry knowledge and products to help customers drive their sustainability agendas and meet their carbon reduction targets,” says Mlalazi.

She highlights that CHRYSO Southern Africa re-invests at least 4% of its sales revenues into R&D each year, emphasising that the laboratory capacity has a strategic role in supporting customers’ key concerns into the future. These include carbon emissions, clinker factors, cement performance and energy saving. The exciting projects underway in its cement laboratory include research into the potential for limestone calcined clay cement (LC3) to drastically reduce carbon dioxide emissions during the manufacturing process.

NEW-GENERATION PLASTICISER USED ON MUSINA BRIDGE PROJECT

An advanced new-generation water reducing plasticiser – CHRYSO® Plast Omega 174 – has notched up another successful application. The product has been used in the concrete mixes for the new Nancefield bridge, which forms part of SANRAL’s Musina Ring Road Project in Limpopo Province. The R640 million project, which allows the N1 to bypass Musina, is due for completion in Q2 2022.

The N1 will pass under the 77 metre long bridge. SANRAL wanted visitors from Zimbabwe and South Africa travelling on the N1 to experience a feeling of being welcomed and the bridge therefore features a prominent pair of 13 metre high ‘hands’ – which are essentially extensions of the centre piers – which express this message. The deck is supported by the columns of the hands and the bridge is aesthetically held on the palms of the hands. 

One of the main reasons CHRYSO Plast Omega 174 plasticiser was selected for the project was that it countered the problem of slump loss.  Due to the available aggregate, ambient temperature and distance from site, CHRYSO Plast Omega 174 was tested and found to be the most suitable admixture. Mix designs were conducted by Matthew Barker, general manager at CHRYSO for technical, mining and export at CHRYSO’s centre of excellence.  

Another challenge was presented by the hot temperatures – up to 45°C – typical of Musina in summer. The concrete temperature needed to be kept under 30°C to prevent thermal cracking. This was achieved by a combination of measures, which included keeping the concrete under shade and cooling it with sprayers, which involved installing a cooling tower to keep the water cool. CHRYSO Plast Omega 174 allowed the mix designs to be optimised, giving more open time on the fresh mix concrete.

CHRYSO Plast Omega 174 was the primary product supplied for the Nancefield bridge and was used for the bridge decks, balustrades and the bridge piers with hands.

Just over 3 000 m3 was required for the concrete of the bridge. The use of CHRYSO admixtures for the mix design was implemented by Jacques Marais, senior plant foreman for the production of concrete at OMV, part of the Raubex Group. The consulting engineers for the project were KBK Engineers.

CHRYSO Southern Africa’s personalised technical service offering and logistics were the deciding factor in OMV using CHRYSO as the main admixture supplier for the project. 

According to Ben Myburg, technical consultant at CHRYSO Southern Africa, “CHRYSO Plast Omega 174 is a multi-dose admixture, which allows concrete to exhibit extended workability characteristics. It improves the cohesion and lowers the viscosity of a concrete mix, which results in an improved homogeneity and compaction, allowing for superior off-shutter finishes thereby eliminating the risk of repairs. By reducing the need for extra water, it increases the durability of concrete by reducing permeability.”

CHRYSO Plast Omega 174 is part of the wider CHRYSO Plast Omega range. Products in the range are ideal for applications such as underwater concrete, pumped concrete, large pours and flowing concrete.

SOLAR ENERGY ADDS TO CHRYSO’S SUSTAINABILITY JOURNEY

Cement additive manufacturing company CHRYSO Southern Africa has installed a solar electricity generating system at its Jet Park premises in Gauteng, as part of its efforts to lower its carbon footprint.

According to CHRYSO Southern Africa CEO Norman Seymore, the system will generate almost 240 MWh each year to serve the company’s production facility.

“This output will make up about 70% of our energy requirements, with the rest sourced from the national grid,” says Seymore. “One of our three sustainability pillars at CHRYSO is the reduction of energy consumption, and this installation goes a long way in reducing our dependence on South Africa’s notoriously carbon-producing electricity.”

A total of 393 solar panels – each with a capacity of 400 W – were installed on the roof of CHRYSO Southern Africa’s premises in January this year. They will collectively generate a kilowatt peak of 157 kWp through five 27.6 kW inverters. 

“Our investment in solar energy generation is an important contribution to the company’s global commitment to a more sustainable construction sector,” Seymore says. “Our CHRYSO admixture products themselves play a valuable role in driving down the carbon emissions related to construction materials.”

He highlights that these admixtures can help to reduce the cement component of concrete – cement being among the world’s most significant carbon-generating products. CHRYSO Southern Africa is also active in other environmental initiatives, such as ensuring that its packaging materials and containers are recyclable and reusable. The company delivers much of its product range in bulk, but uses recyclable material where products are delivered in 200-litre drums or 1,000-litre containers.

“We have, in addition to our solar installation, also implemented a series of wastewater treatment systems at our plant to reduce and recycle the volumes of wastewater we produce,” he says. “We constructed several wastewater catchment areas to ensure that any discharged wastewater was first treated to an acceptable standard.”

CHRYSO IS PARTNER IN PIONEERING HARDSTAND LAUNCH

An innovation in concrete pavement construction was recently launched in Johannesburg, pointing the way to the future of external hardstands, according to Hannes Engelbrecht, Concrete Unit Business Director at CHRYSO Southern Africa.

The pioneering solution – Optipave VRS – is a collaboration between leading players in the field. It combines the volumetric retraction stability (VRS) additive Link EVR from RCR Industrial Flooring, thin concrete paving (TCP) short-slab design technology and fibre-reinforced concrete.

“CHRYSO® EasyFinish is a macro monofilament fibre that is engineered to replace steel mesh or steel fibres in concrete,” says Engelbrecht. “It is specially designed for concrete reinforcement and is shaped to create a smooth concrete surface finish, improving durability and mechanical properties.”

Link EVR reduces shrinkage and curling in concrete slabs, and also prevents superficial micro cracks known as crazing. It makes concrete less porous, improving its freeze-thaw behaviour as well as its resistance to liquid spillage and abrasion. 

The Monofloor TCP design ensures that only one set of wheels can load each slab at any one time, reducing the flexural stress and changing the failure mode. The result of this is that a thinner slab can be cast for the same loading. 

“Together, these technologies solve recurring problems in conventional external concrete pavements and hardstands,” he says. “Optipave VRS, a technology from the RCR Industrial Flooring Group) reduces tensile stress in the slab, eliminates the negative effects of curling and pumping, reduces slab thickness, and allows minimal joint opening and maintenance.”

The Optipave system is also environmentally friendly as it has a low carbon footprint, absorbing just 500 g/m2 of carbon dioxide. It is recommended for a wide range of applications including highways, industrial pavements, low-traffic roads and parking lots.

“We believe that the Optipave system has a bright future due to its competitive construction costs and ease of installation,” says Engelbrecht. “The optimised load distribution system and latest technologies in concrete also give Optipave a longer lifespan. This further enhances its cost effectiveness.”

The launch, which took the form of a practical demonstration where sample panels were cast, raised the interest of contractors, property developers and consulting engineers alike. 

AVOID CONCRETE CRACKING IN DRY CONDITIONS

Hot and windy conditions can lead to plastic shrinkage cracking on fresh concrete, but CHRYSO® ProFilm 19 can solve this problem, without the addition of extra water to the concrete mix. 

One of the dangers of working in low humidity conditions – even inside heated buildings during cold weather – is the rapid evaporation of surface moisture from the concrete. This can cause map cracking and plastic shrinkage, where cracks can penetrate to the full depth of a concrete slab.

According to the American Concrete Institute (ACI), plastic shrinkage cracking of concrete is likely to occur whenever the evaporation rate is more than 1 kg per square metre per hour. The ACI highlights that this rate of evaporation can be readily caused by many combinations of air temperature, relative humidity, concrete temperature and wind velocity. 

As an evaporation reducer, CHRYSO® ProFilm 19 prevents this cracking by protecting fresh concrete from the effects of excessive moisture loss in rapid drying conditions. Furthermore, it can achieve this result without increasing the bleed. By spraying this evaporation-reducing product onto fresh concrete surfaces, the user creates a continuous mono-molecular film over the concrete, which inhibits the rapid loss of bleed water. 

This film lasts as long as the concrete remains plastic, even where floating and trowelling operations must be conducted to create the required surface finish. CHRYSO® ProFilm 19 is a water based product which is compliant with guidelines on volatile organic compounds (VOCs).

The effectiveness of the mono-molecular film means that there is no need for water spraying on the surface of the concrete in order to slow the evaporation process. It can be used on a range of horizontal concrete pours where the evaporation rate may exceed the bleeding rate of concrete. These applications include industrial floors, roads, bridge decks, slabs, patios, driveways and sidewalks.

CHRYSO® ProFilm 19 is ideal in concrete applications that produce little or no bleed water, such as mixes with low water content.

CONCRETE WIND TURBINE TOWERS GET CHRYSO TREATMENT

In wind farms all over South Africa’s Eastern Cape and Western Cape provinces, CHRYSO Southern Africa is adding value to the precast concrete segments used to construct the 100 metre tall wind turbine towers.

The average concrete turbine tower comprises 18 precast segments, each with a height of between 18 to 20 metres and a diameter of between 600 mm and two metres. In the manufacture of these precast elements, the production speed and segment uniformity are essential. This demands high early strengths to ensure fast erection, while giving the towers an ability to withstand demanding fatigue loads. Wind turbines must also be able to perform in some of the country’s harshest working environments, making durability a key requirement for the concrete mixes used in precast units.

The CHRYSO® Fluid Premia range of plasticizers facilitates workability retention of between 30 and 45 minutes while achieving high early strengths. These early strengths allow for the fast erection of the towers owing to the quick turnaround time as the mould release and pre-stressing release can be done earlier. optimises early and late age strength development in concrete mixes.

The CHRYSO® Fluid Premia range maintains consistency in the manufacturing of reinforced concrete components, reducing the sensitivity of concrete to variations in water content.

Plastic shrinkage cracking and plastic settlement cracking can occasionally penetrate deep into a precast unit, causing significant cost in remedial measures and even replacement. Applying a curing compound from the CHRYSO® Cure Range to the precast segments reduces the incidence of shrinkage cracks and promotes better strength gain characteristics. Curing compounds also increase the impermeability of concrete, making it more durable.

Another important product gaining traction in this market is a.b.e.® duragrout. Developed especially for wind farm precast applications, this product which is proving popular is being used to level segment holders. The duragrout WF product is used for grouting and bedding of structural elements; it can be pumpable or gravity fed and has good cohesive properties without bleed or segregation. It is pre-blended and ready-to-use, requiring only clean water to be added.

In a related development, CHRYSO has partnered with Maturix to develop an innovative sensor solution with a digital cloud platform to monitor the maturity of concrete. It has been used worldwide on more than 350 in-situ and precast projects, and is being trialled on a wind farm project in South Africa. This cloud-based solution helps the construction industry to monitor concrete curing and hardening through hydration temperature measurements.

CHRYSO SOUTHERN AFRICA LEADS WITH FIBRE SOLUTIONS

CHRYSO Southern Africa offers outstanding solutions when it comes to fibre reinforced concrete. A mutually beneficial partnership with Oxyfibre has resulted in world class products being available locally, supported by expert fibre technology development and consultancy capabilities. 

Izak Louw, general manager at Oxyfibre, says that CHRYSO’s presence and established infrastructure in Southern Africa made them the partner of choice for making Adfil fibres available in Southern Africa.

CHRYSO® EasyFinish, as a macro fibre, optimises speed of construction by eliminating the need for costly placement of rebar and ensuring adequate cover to reinforcement. Added benefits include smooth surface finishes, maximum bond, greater tensile strength per fibre for enhanced residual flexural strength and toughness in the concrete. 

For micro fibre applications, CHRYSO® Fibrin XTserves as alternative to crack control mesh. The use of micro fibres in concrete product manufacturing has proved to enhance the surface properties and durability, significantly reducing the occurrence of plastic shrinkage and plastic settlement cracking.

Recent projects where these fibres have been used include the placing of 7000 m2 of concrete in very thick surface beds and several large warehouse floors. Other applications have been in coastal defence structures and shotcrete in the Western Cape, as well as for the construction of floors in the farming and food processing industries where harsh chemicals and other deleterious substances could potentially affect the concrete. All these projects reported noticeable cost and time savings. 

Louw says that ongoing research has resulted in new fibre solutions that will be available shortly. These include Ignis, a micro fibre specifically designed for its fire protection benefits, and a macro fibre that will address problem areas in the precast industry.

Fibre technology is used extensively in readymix concrete, but the ease of transport, storage and handling of these fibres also makes them ideal for smaller projects and on-site mixing.

The CHRYSO Southern Africa / Oxyfibre partnership has created a win-win solution for all stakeholders providing concrete reinforcement solutions for construction projects to be undertaken safely and rapidly with reduced waste and reduced impact on the environment.

CHRYSO DECO WASH PICO GIVES THE PERFECT SANDED FINISH

CHRYSO Southern Africa offers a comprehensive range of products to optimise the placing, performance and aesthetics of concrete. Particularly in the field of decorative concrete, CHRYSO has become a leader in addressing the need for quality, durable and inspiring surfaces and finishes. 

One such a product is CHRYSO® Deco Wash Pico, a surface retarder that lightly delays the setting of the concrete surface layer. Following the correct application and washing-off procedures will result in a finished look of a “sanded” or “acid washed” surface.

Before application, all surrounding supports and elements for which the product is not intended must be covered. No bleed water must be visible on the concrete surface and troweling and smoothing should have been completed. After thoroughly mixing the product, it is sprayed uniformly onto the surface of the fresh concrete. This water-based solution forms a thin film that is resistant to fine rain and high temperatures.

Depending on weather conditions, the product should be washed off with a high-pressure washer within 24 hours to reveal the surface effect. For a better homogeneity and detail, a preliminary brushing with a single nylon brush machine is advised. To ensure a uniform appearance, it is important to keep to the same washing-off time for all parts of the project on a given site. Time windows may vary in case of significant temperature variations.

CHRYSO® Deco Wash Pico is suitable for use on walkways, pool surrounds, patios, and areas open to public pedestrian traffic. 

CHRYSO Southern Africa’s sales and technical teams are on hand to discuss how CHRYSO® Deco Wash Pico can add aesthetic appeal to a concrete surface.

CHRYSO® DEM RANGE PLAYS CRUCIAL ROLE IN FORMWORK

CHRYSO Southern Africa’s commitment to provide quality solutions for the built environment, is evident in the CHRYSO® DEM range of application driven release agents.

Understanding the crucial role formwork plays in the production of quality concrete and similarly moulds in the manufacture of precast elements, the CHRYSO® DEM range has introduced much needed flexibility to the industry. Previously, it had been a case of one-size-fits-all when it came to release agents.

Discerning clients, developers, manufacturers and specifiers are increasingly particular about the aesthetics of concrete finishes. To achieve the desired texture and colour finish on the concrete’s surface it is imperative that formwork surfaces are adequately prepared in terms of cleanliness and that an optimal release agent is selected for the application.

As different form-face materials have varying longevity, absorbency and texture characteristics, specialised release agents are required to realise the full aesthetic potential of the formwork, eliminating wastage of time and materials.  

Not only will the optimal release agent reduce the likelihood of imperfections and surface defects (particularly blow holes) in the concrete, when applied correctly it will also ensure no staining or deviation from the specified colour finish.

The top quality release agents in the CHRYSO® DEM range provide greater coverage, are easy to use and add consistent quality, which is important on construction sites as well as in precast plants.

CHRYSO®Dem Bio 10 is a vegetable-based, bio-degradable and non-toxic release agent, which will not pollute the environment. It has a low odour and is therefore safe to use in confined spaces such as mining, tunneling and any poorly ventilated areas. It is suitable for use with all types of formwork: metal, wood, plastic, polystyrene and fibreglass.

Another product in the range is Elio VP, a hydrocarbon oil-based agent, which is suitable when producing concrete pipes with roller compacted pipe technology. The Elio VP significantly reduces surface defects. The low viscosity oil creates less surface tension against the sides of the pipe steel moulds which results in less outer concrete surface damage when demoulding.

CHRYSO® Dem Oleo WB is a wax-based delayed-release agent for wooden formwork used on conventional jobsites and for wooden pallets for cement-based brick manufacturing. This release agent temporarily protects and extends the life of veneer laminated shutter boards, decreasing the frequency of re-lamination. This release agent can also be used to coat pallets for protection, when stacking cement-based bricks on them.

CHRYSO® Dem Oleo FW is a hydrocarbon based, which is suitable for use with all types of formwork. It is however not suitable for precast applications. It ensures ease of formwork release and also temporarily protects and extends the life of metallic formwork from corrosion.

CHRYSO® DEM Oleo SM is a mineral-based delayed-release agent, ideal for use with metallic or wooden formwork for wet precast. It does not stain or affect the colour of the concrete when applied correctly. It is the perfect solution when white cement is used for specialised architectural finishes. CHRYSO® Dem Oleo SM can handle the high temperatures of steam curing and provides rust prevention. This release agent is a hydrocarbon oil-based delayed release agent, used for steam cured precast elements cast in steel formwork.

CHRYSO® Dem Oleo RT is a hydrocarbon oil-based, delayed-release agent for the roof tile industry, developed specifically for use with aluminum roof tile pallets.

This ready to use range of release agents reduces the likelihood of errors, which may occur in other release agents, where mixing of various components is required.

When applied correctly and for the specific purpose, the CHRYSO® Dem range does not modify cement hydration and as it is water repellent, it is not affected by rain.

These products are manufactured locally by CHRYSO Southern Africa at its production plant based in Jet Park, Johannesburg and comply with regulations for the transport and disposal of hazardous materials.

While generally regarded as a minor item on the bill of quantities, the specification and selection of an appropriate release agent and application method may prove to be critical to the success of the project, affecting both the quality and colour of the surface finish. A release agent is a low-cost item, yet vital in relation to the cost of formwork and moulds. It thus makes sense to use the appropriate release agent for the correct application and formwork substrate, in order to protect and extend the life of the formwork or mould, ultimately resulting in financial benefits.

As each release agent contributes differently to the off-form finish, care in the selection of the release agent is critical.

CHRYSO Southern Africa’s sales and technical teams are on hand to discuss the correct CHRYSO® DEM solution for any application, condition or aesthetic specification.

REFURBISH OLD CONCRETE SURFACE EASILY WITH TEXTURE TOP®

Texture Top® offers the ultimate decorative solution to save money and time by refurbishing old concrete surfaces.

Ageing, worn or surface damaged concrete no longer has to be demolished and recast at a cost to the customer and the environment. Instead, Texture Top®, a CHRYSO Southern Africa product, can be used to enhance existing surfaces through renovation and repair.

Texture Top® is a polymer-modified cementitious coating which could be applied either with a spray gun or trowel to obtain a specified finish. The spray technique allows coverage of large surfaces in a short time.

At an application thickness of merely 2 mm, this thin anti-slip coating offers excellent mechanical resistance. The product is available in a standard range of colours, and could be custom pigmented to complement various finishes.

Texture Top® can be applied to achieve any textured or smooth finish. This is a simple and durable solution to renovate and add aesthetic value to surfaces around swimming pools, paths, terraces, driveways, patios, floors and stairs, as well as interior and exterior walls.

CHRYSO Southern Africa’s technical and sales teams provide leading edge expertise in support of Texture Top® which makes it easy to achieve customised modern and trendy decorative finishes in a cost-effective and environmentally responsible way.