ROCLA AND TECHNICRETE FUND TSEKERE PRIMARY SCHOOL UPGRADES

Rocla and Technicrete, part of the Infrastructure Group of Companies (ISG), funded the conversion of 14 pit latrines into flushing toilets and supplied associated paving and concrete structures at the Tsekere Primary School, Ga-Raphahlelo in the Limpopo Province. The total funding by ISG for the project was R350,675.00.

“Tsekere Primary School had 14 pit latrines which were not in a good condition or really usable, so they were sealed and then converted into flushing toilets” commented Malebusa Sebatane, Group Marketing and Communications Manager for ISG. “We decided to fund the upgrades to their sanitation system in order to provide clean and safe sanitation units for the pupils of the school, as ISG believes that every school should have properly functioning sanitation units. Every child has a right to personal dignity”.

Sebatane added “We appointed Enviromould Product Solutions to install the Rocla designed and Agreement approved, Eaziflush low flush toilet pedestals with a child seat lid incorporated. Included in our donation was funding for septic tanks, cisterns and all the associated plumbing components. We provided funding for the refurbishment of the roofing sections and repainting of the toilet doors.  An additional two Rocla manufactured Sanitation Community Cast Toilet Top Structures were also supplied which increased the total number of toilets to 16.”

Rocla’s precast concrete sanitation units are a cost-effective solution to one of the most basic and essential needs in South Africa – the need to supply clean, hygienic and cost-efficient sanitation not only to schools but also to the homes of people living in rural areas. All of Rocla’s sanitation units are designed as water saving units that can function on the existing grey water output from a household rather than requiring fresh drinking water.

Additionally, Technicrete supplied 90 square meters of 50 mm grey Bond Brick pavers that have been installed around the sanitation units and the school’s hand wash basins. Technicrete’s Bond Brick is particularly suited to this kind of environment due to its durability and sturdiness.

The associated transportation costs for Rocla and Technicrete’s precast concrete products to site was also funded by the ISG.

“ISG is proud to have funded these sanitation and infrastructural upgrades, which the school so clearly needed. Inside the classroom, ISG donated R4,000.00 worth of calculators for the learners to use with their studies – safety and hygiene outside of the school coupled with educational supplies for inside use, will hopefully make an impact upon the learning experience” concluded Sebatane.

BRIDGING THE GAP

Outlying rural areas are often confronted with major inconveniences when severe storms or the rainy season comes around. Roads become flooded, bridges submerge under water or are completely washed away, cutting off communities from food supplies and essential services. Gadiboye Village, near Kuruman in the Northern Cape is such a location. Rocla recently supplied Rectangular Portal (RP) culverts and bases and the link slabs to ensure that the storm water was effectively dispersed without cutting off the Gadiboye Village community from its school and shops.

Rocla Sales Consultant, Dillon Carter, said “The Gadiboye Village project required RP culverts measuring 3600mm x 3000mm with RP bases of 3600mm. Rocla is the only company that manufactures RP culverts of this size and we manufactured 32 for this particular project”.

“The installation is unique, and a first in terms of bridge design in South Africa, in so much that four rows of eight culverts in length were installed in a culvert-link-culvert-link formation” said Carter. Bolts and anchor grout were required to secure the slabs to the culverts and were supplied by Rocla and Technicrete Mining Division, as well as a crane, which was hired by South 32 Mine, the project investor, to offload the culverts at site.

“An integral part of this culvert project was the 24 3600mm link slabs that we supplied which were crucial to the formation of the culverts for this particular application. The style of the formation was not unsimilar to a truck and trailer concept” said Carter.

Rocla’s pre-cast concrete RP Culverts are recommended for use in storm water applications, they provide a waterway underneath road. The unit consists of a deck and two legs and placed on a concrete base. The RP Culverts have also been used at railway tracks, mine tunnels and also can be inverted as a drainage ditch.

The culverts are normally supplied in 1,22m lengths and in 50S, 75S and 100S strength classes, but custom-made designs can be manufactured as they were for the Gadiboye Village project.

Special intermediate strengths or heavier loading requirements can be designed and manufactured but would be subject to various material constraints and would need evaluation by our engineers on an ad hoc basis.

“One can easily forget about the sometimes dire situations our communities find themselves in outside of our main city centres, but we believe that our culverts and associated components will make a tremendous difference to the Gadiboye community once the rainy season commences” concluded Carter.

SPUN CONCRETE POLES FOR POWER: TRANSMISSION AND DISTRIBUTION

Transmission and distribution power lines in suburban and rural areas need poles that can withstand harsh environments, inclement weather and vandalism, in order to ensure the continuous supply of electricity. Rocla’s spun concrete transmission and distribution poles are well suited for the exacting requirements of electrical distribution line construction.

The durable, maintenance free spun concrete poles are exceptionally strong through 360 degrees, whereas normal cast concrete poles have a major and minor load axis. The unique centrifugal manufacturing process gives a uniform densely compacted concrete along the whole length of the pole. This gives the Rocla spun concrete pole extra strength properties, not found in cast concrete poles.

Spun concrete transmission and distribution poles offer a cost-effective solution due to small servitude requirements, simple and economic funding methods and a quicker installation turnaround time. They offer a durable, long-term solution with minimal maintenance. Rocla spun concrete poles systems are ESKOM approved and have been tested at Eskom’s Rosherville Testing Station.

A bonus for the farming community as a result of the systems small servitude requirements is that is well suited to intensive farming on high-value land.

Rocla offers a variety of pole lengths in single, jointed and double pole solutions, and Rocla’s engineering technical team are able to customize spun concrete pole solutions to meet specific customer sizing requirements as well as design and manufacture products for non- standard applications.

Spun concrete poles offer a lifespan of over 50 years.

Rocla manufactures a range of concrete pole solutions for electrification, reticulation, telecom masts, lighting, security monitoring and stadium use.

ROCLA, THE LEADING MANUFACTURER OF SEWERAGE AND WATER SYSTEMS

With a country in constant development, be it new commercial or residential projects or the maintenance or upgrading of existing roads, pipes and storm-water systems, a crucial factor is the application of water and sewerage systems and related products that offer developers and local municipalities the longevity and high quality required.

With a history spanning over 100 years, Rocla, has been a leader in the manufacture and supply of sewerage and water systems and has worked with local municipalities and civils contractors throughout South Africa. The technical expertise and assistance that Rocla offers in the water and sewerage sectors in particular, puts them in an enviable position of assistance on projects from inception to completion.

One of the flagship products from Rocla is their reinforced concrete pipes with HDPE lining, which offers sewerage projects the same advantages as a conventional concrete pipe or a plastic pipe in that it maintains its shape under load and is resistant to acid attack. Exposed concrete in the joints of a pipeline need to be protected against corrosive gasses, and Rocla has designed a HDPE capping strip which is welded over the joint of the pipe after installation. It is generally 200mm wide and the same thickness as the lining used in the pipe. This unique HDPE lined pipe was recently commissioned for the Polokwane Waste Water Project, and 19kms of HDPE piping was supplied.

Rocla also manufactures reinforced concrete pipes with sacrificial layers. The host pipe may be manufactured from Dolomitic aggregate and ordinary Portland cement or Siliceous aggregate and ordinary Portland cement. The sacrificial layer may be from Dolomitic aggregate and ordinary Portland cement or Dolomitic aggregate and calcium aluminate cement.

The exposed concrete in joints of a pipeline needs to be protected against corrosive gasses and Rocla recommends joint sealing processes to avoid sewer corrosion activity.

Projects such as the Nellmapius Ext 22 low cost housing contract near Mamelodi commissioned nearly 3,000 precast steel-mesh reinforced concrete storm water pipes of various nominal diameters from Rocla, for the six-kilometer storm water pipeline being constructed.

Rocla was selected to manufacture and supply all the storm-water (spigot and socket) and interlocking pipes for Waterkloof Quarry, an old 58-hectare landmark, situated on the border of Waterkloof Ridge and Monument Park near Pretoria which was developed into an upmarket retirement estate. It was Rocla’s manufacturing capability that enabled them to meet the tight deadline associated with the quarry development.

Reinforced concrete pipes with Xypex Bio-San C500 are supplied for 300mm to 600mm pipes. Xypex Bio-San C500 is a uniquely designed admixture for integral, long-term protection of concrete in harsh sewerage conditions which have high levels of H2S that cause microbial induced corrosion in pipelines. The protection is for the full wall of the pipe and eliminates extra joint sealing.

For the recent Diepkloof sewer upgrades 2,715 piping product and associated supplies comprising RJ pipes, rubber rings, man holes, cover slabs and concrete lids for this were sourced from Rocla due to the quality of its manufacturing processes and final product.

Accessories for sewerage and water projects also include pipes with access holes, bends – Rocla can supply custom made bends of up to 30 degrees – spigot and socket pipe systems, manhole chambers with HDPE lining and reducer and cover slabs.

The Rocla design, engineering and technical team is available for pre-site design, and on-site application advice when required. This way, Rocla ensures that the correct solution is selected and installed correctly, giving the client a maximum return on their investment.

RAINWATER HARVESTING – WHAT STANDS IN ITS WAY?

With water shortages and the longer-term security of water supply being a serious concern for South Africans, one would think that every business, school and home would have a rainwater harvesting system. Justin Kretzmar, Sales Engineer at Rocla and Technicrete, explains why this is sometimes not the case.

“When constructing new commercial, residential and public buildings, a rainwater harvesting system is one of the last elements to install. At this stage, many projects are either over budget or have run out of money completely, and so the idea is often abandoned or a cheaper, shorter life span option adopted.

“Another reason is that rainwater harvesting systems are still being underquoted in South Africa at tender phase. If the requirement is for 50,000 litres of harvesting, we often note at a later stage that 10 of 5,000 litre plastic, above ground, storage tanks have been used as the pricing guideline. Consideration might not have been given to the site plans and hence an understanding as to where the engineers envisaged these tanks to be placed. On sites where the tanks are designed to be placed below ground, due to durability, overall size and/or space requirements, the plastic guideline pricing can be out by a factor of 10 or even 20 once you include below ground installation work.

Mr Kretzmar maintains that rainwater harvesting is also sometimes viewed as a nice-to-have as opposed to a necessity and hence gets dropped at the final stages due to updated overall cost implications.

“There is little financial incentive, and no legislation that forbids the use of potable water when non potable water could be used. However, with parts of our country either suffering from drought, or experiencing water shortages and restrictions, there has been an increased interest in residential rainwater harvesting. Unfortunately, many people only consider rainwater harvesting in times of drought, which of course, is too late. There has to be rain to fill the tanks and we hence, need to embrace a longer-term philosophy.” says Kretzmar.

Product offering

Technicrete and Rocla, part of the Infrastructure Specialist Group, both offer different water harvesting friendly options that can be used independently or combined for a holistic solution. These include permeable paving solutions to capture surface water and below ground concrete collection tank systems for roof water capture.

Rocla offers two concrete rainwater harvesting solutions that are both installed underground:

  • A (smaller) modular system, made up of 6,000 litre units that can accommodate storage requirements from about 24KL up to hundreds of thousands of litres.
  • A (larger) modular made up of 60KL rectangular tanks. These are more cost effective than the smaller modular option but installations must be increments of 60,000 litres.

Below ground concrete tanks are considerably more hygienic when compared to above ground plastic alternatives due to the naturally cool and dark environment where most micro-organisms cannot survive. Being underground and out of site, vandalism is reduced and as they are not exposed to sunlight, problems associated with UV reducing overall lifespan are alleviated. 

Technicrete’s Aqua range of permeable paving products subscribe to a methodology whereby vertical ‘slots’ between adjacent pavers provide drainage channels allowing storm water to flow from surface, through the paving and bedding layers, into suitably designed stone layer works below.  This stone layer becomes the storage ‘tank’ with the captured water replacing air cavities between adjacent stones. It is interesting to note that these air cavities can be up to 40% of the overall volume of this layer, or 40 litres of water stored per square meter in every 100mm thick stone layer. Whilst permeable paving is most frequently used as a water attenuation facility, it can also be used for rainwater harvesting, by placing an impervious membrane at the base of the layer works, capturing the water instead of infiltrating it. This water would typically be used for reuse in greywater and irrigation systems. 

Potential problems

“While permeable paving technology has been around for well over 40 years (locally for over 20 years), some engineers are still hesitant to make use of this option. Permeable paving can and does fail when it has been designed or installed incorrectly or has been placed in unsuitable locations,” says Kretzmar.

For instance, one should probably not use permeable paving in places where there is a lot of fine dust and pollution that can be expected to blow over an area on a regular basis. As such, there is justifiable concern about the long-term clogging of permeable paving. With the finest material at the top, grading to larger stones at the bottom, clogging occurs when tiny particles being transported by storm water get caught by the smaller gravel at the top of the pavement layers and hence reduce the filtration capacity through the paving layer. This reduces the filtration capacity through the paving layer and the functionality of permeable paving.

Other causes of failure include design and installation shortcomings where the permeable layer must contend with more surface water than it can physically process. One should ensure there is a limit to a ratio of 2:1 ratio of impermeable to permeable layering. Furthermore, contractors often do not follow correct installation instructions with regards to contamination and compaction.

“Maintenance and cleaning of permeable paving is therefore very important. Maintenance should include annual sweeping of the paved area, prior to the rainy season as this will remove most of the silt that has settled onto the area over the dry season – therefore avoiding contamination at the top grit layer.  Typical cleaning regimens should be carried out every five to ten years or as and when as system is no longer functioning as required. A high pressure spray will loosen the upper 25mm of clogged, polluted gravel/grit, followed by a high strength vacuum to remove this material. The fine grit layer between pavers must then be reinstated with new, clean and washed material.” adds Kretzmar.

Kretzmar concludes that rainwater harvesting tanks and permeable paving have been used very successfully internationally and moderately so in South Africa, “However, both systems have been very successful in other countries, especially where the requirement has been driven by local legislation and municipalities.”

Source: Water & Sanitation Africa Mar/April 2021

ROCLA SUPPLIES 19KM’S OF HDPE PIPES FOR POLOKWANE WATER TREATMENT PLANT

Waste water treatment plants play a crucial role in the removal of contaminants from wastewater and sewage in order for its conversion into an effluent that can be returned to the water cycle in an environmentally friendly way or to be reclaimed for other purposes. It is a critical process in the supply of safe water to local communities.

Rocla’s HDPE vertical cast pipes were specified for two phases of the Polokwane Waste Water Treatment Project due to the quality of the pipes and the technical support Rocla provides. The project commenced in 2018 and was completed at the end of December 2020.

The project, which was subdivided into three phases, is based in the Seshego area in Polokwane. It was initiated to upgrade existing sewerage system, to meet the increased requirements of the Seshego local communities. Each phase of the project had a separate starting point with a common joining at a single point.

Rocla, Regional Sales Manager, Andrew Kruger said “The project was commissioned by the Polokwane Municipality to upgrade a now outdated sewerage system which no longer met the local community’s requirements in the Seshego area of Polokwane. We worked closely with site contractor Safcrete Construction so that the quality of the pipes would be to the standard required and delivery scheduling would be as seamless as possible”.

“The pipes were 2.5m Silica Rolling Joint Pipe, comprising a 3mm sacrificial layer. Five sizes of pipe were required, namely 900mm, 1000mm, 1200mm, 1400mm and 1500mm, which if placed end-to-end, the HDPE piping would be over 19 km’s in length. The placement of each pipe required the insertion of a rubber ring and the welding of a ‘capping strip’ on the inside of each individual joint to ensure proper sealant” said Kruger.

Rocla’s HDPE lining offers water and sewer projects advantages such as a surface smoother than concrete, enabling smaller internal diameter piping to be utilised. The long-term pullout strength of the lining anchors is able to cope with a ground water pressure in excess of 10m.

Mr Thaver, Safcrete Construction’s Contracts Manager commented that he had worked with Rocla and their engineers on many projects over the years and had always been impressed with the quality of the end product supplied. “The Rocla HDPE pipes were specified for this project because they offer the best solution to waste and stormwater plant and projects of this nature. Their attention to customer requirements, in this case, an exceptionally challenging delivery schedule, is also a feather in their cap”.

Kruger added “In order for our Polokwane factory to manufacture the various sizes of pipes and the required quantities, Rocla Polokwane underwent an overhaul in terms of the manufacturing sections needed to accommodate the upgraded equipment. We also made use of special Vertical Cast (VC) moulds which were required for use with the insertion of the sacrificial layer within the pipes. It was these changes that enabled us to meet the quantities of HDPE pipes required for the Polokwane Waste Water Treatment Plant projects as they enabled us to increase our production schedules and deliver to site timeously”.

Concrete pipe with a cast in HDPE lining has all the advantages of a strong rigid pipe that keeps its shape as well as those of a plastic pipe that is inert to acid attack.  It is the best pipe for large diameter gravity pipelines in almost any condition. Standard HDPE lining is light green and 3mm thick. Different colours and thicknesses can be supplied.

The range of products that Rocla offers in terms of sewer reticulation are:

a) Reinforced concrete pipes with a HDPE lining.

b) Reinforced concrete pipes with a sacrificial layer.

c)  Reinforced concrete pipes with Xypex BIO-SAN C500 (300mm – 600mm diameter pipes.

ROCLA MANUFACTURES LARGEST CUSTOM DESIGNED JACKING CULVERTS IN SOUTH AFRICA

When the local municipality of Tshwane required 3m x 3m custom-made jacking box culverts for a service delivery project at Iscor Heights, in Pretoria West, the only company in South Africa who was able to design and manufacture culverts to such large specifications was Rocla. The culverts were manufactured with an in-the-wall joint that can be sealed with a rubber ring if required.

The project, which required 90 large sized culverts to create two 50m long under-road tunnels 6m below the road surface in order to provide new water services to the area, commenced in January 2020.

Brendan van Vuuren, Sales Consultant for Rocla said “We have been involved with the Iscor Heights project since the inception of the tender, and we worked closely with Esor Ltd, one of South Africa’s benchmark and civil engineering groups, who was the project’s sub-contractor, in order to ensure that their specifications for these very large jacking culverts were met. The largest jacking pipe Rocla had manufactured in the past was a 3000mm x 2500mm, which was too small for the project. After all of the specifications were finalised, the designing process began, which included manufacturing the mould for this specially sized culvert”.

Esor Ltd, Director, Len Nel commented “We have worked with Rocla on various projects over the years, so we knew that these large jacking culverts would have to be specifically designed and manufactured, and that Rocla was the only company who had that kind of creative capability”.

“After many meetings to discuss the design and verify the technical requirements of the jacking culverts to ensure that the final product would meet the loading requirements, the final culvert weighed in at an excess of 10 tons per product – a major design and manufacturing coup for Rocla” Nel added.

The timeframe from approved product specification and design to mould completion was only 16 weeks for the 90 culverts.

Due to the enormous size of the culverts, the delivery to site required an abnormal load permit and they were offloaded into the pit at site with a Side boom Crane.

“Rocla is extremely proud to have been involved with this unique project. It tested our design team’s expertise and our manufacturing processes to the limit, but showed that no project is too big for Rocla to collaborate on. It will certainly become one of Rocla’s historical milestones” concluded van Vuuren.

Rocla manufactures various culvert designs and culvert base slabs, along with stormwater pipes and other infrastructure products such as HDPE and pressure lined sewage pipes, concrete poles, manholes, bus shelters, sanitation units and concrete cabins.

12 METRE FULLY INSULATED CONTAINERISED OPEN PLAN OFFICE UNIT AND PAVING DONATED TO MPUMULANGA PRIMARY SCHOOL BY ROCLA AND TECHNICRETE

The Infrastructure Specialist Group (ISG), which comprises Technicrete and Rocla has donated a 12 metre fully insulated containerised open plan office unit as well as paving to the Sifunindlela Primary School, based at Kabokweni in Mpumalanga Province. The office unit will be used by the school’s principal, Mr Ndhlovu and some of the school’s administration staff.

The 1 x 12.22 m x 2.44 m x 2.59 m container is fully insulated with 40mm polystyrene, has four aluminium sliding windows (900 mm x 1200 mm) – complete with fitted burglar bars – and a steel panel entrance door with a lock set.

Principal Ndhlovu explained “Sifunindlela Primary School has never had offices for staff, staff have in the past, met for meetings in passages or under the Lapa. Now, with the donation of this containerised office unit we have privacy for meetings with staff and visitors. It enables us to house school records and confidential correspondence properly. We are very grateful to Rocla and Technicrete for these donations. It creates a proper working environment for myself and members of my team, making a difference to how we work and giving us all a sense of pride in the school we are managing”.

“In 2019 ISG donated 16 sanitation units manufactured by Rocla to the Sifunindlela Primary School, because we believe that proper sanitation in schools provides human dignity. It was during this project that we became aware of the fact that Principal Ndhlovu had no dedicated office space not only for himself but also for some of his administrative staff “commented ISG Group Marketing and Communications Manager, Malebusa Sebatane.

“ISG decided to donate this fully insulated open plan office space to the school to assist in providing a secure and stable office environment for Principal Ndhlovu to carry out his duties” said Sebatane, adding

“Technicrete has also donated 2,574 m2   of our Double Zig Zag 60 mm grey paving and financed a local contractor to clear the ground work and install the paving around the school and new office”.

“In the past the primary school children have been subjected to high levels of dust from the dirt tracks around the premises, which the Technicrete paving will help reduce if not eliminate completely. Installation is from the entrance to the primary school, around the art class and around the netball fields. The paving will improve the health and wellbeing of these young children in a big way in addition to creating safer and more durable walkways” concluded Principal Ndhlovu.

The containerised open plan office space is fitted with a 220V Distribution Board, 4 x 4 ft vapor proof lights, 4 x double switch plugs, a single light switch, 1 x 1800 BTU type air conditioner. The unit has rubberised flooring with black pigmentation. The exterior of the unit has been wire brushed, primed and painted in A/D white enamel.

“Education in South Africa is of paramount importance, if ISG, in some way, can make a difference by providing a suitable environment for educators to perform their duties in and safe and hygienic sanitation units for learners like those we have met at Sifunindlela Primary School, then we believe we have a played a part in the general upliftment of their environment” concluded Sebatane.