Australia’s wastewater infrastructure faces significant challenges from Microbiologically Induced Corrosion (MIC), leading to the degradation of concrete structures. Cemspec specializes in providing advanced, durable lining solutions specifically designed to protect and rehabilitate critical assets like trunk sewers, manholes, wet wells digesters, grit chambers, drop structures, pumping stations and treatment plants against aggressive chemical and biological attack. We do not believe that one product is a magical cure.
What Do You Really Need?
As a rough guide we have linked some options to product pages below. This is not a definitive guide and is no substitute for a proper discussion and a complete outline of your project.
Trunk Sewer with heavy corrosion.
we recommend you build up the corroded areas firstly with a cost effect structural Shotcrete and then protect with a CAC Gunite
Trunk Sewer with moderate corrosion
Reinstate original profile plus an extra 25mm of CAC Gunite
Municipal Wastewater structures with heavy corrosion
Spin our silica free shotcrete to reinstate structural integrity and coat with GoonaGuard or GGVSV
Municipal Wastewater structures with light corrosion
The Science
Let’s start with, what is the environment we are working with? What are the H2S levels or temperature, ventilation or any other information that can help. For instance, most corrosion happens above the waterline. H2S is heavier than air and may or may not smell depending on the concentration. It is this H2S gas that feeds the bacteria on the walls of enclosed sewer structures. It comes from the wastewater stream and be warned it can kill! Anyway, these bacteria on the walls of the structure thrive in these wet dark environments and produce mostly Sulfuric Acid. The pH drops and other bacteria colonise dropping the pH further and further and the cycle continues to as low as pH=1. At these levels Ordinary Portland concrete, grouts or mortars don’t stand a chance. But what is not so well known is the role of fungi which starts this whole mechanism. If you want more detail on how these mechanisms work and how our products interact don’t hesitate to ask
Joint Venture GGVSV – CAC Shotcrete
Whether it is a large jobs like trunks sewers using hundreds of tons of shotcrete or something small like spinning a manhole, it is hard to beat the corrosion resistance of a nearly “100%” CAC. Having lived and breathed it for nearly 2 decades all over the globe, we have seen what it can and can’t do. GoonaGuard VSV can be Dry Spared (Gunite), Wet sprayed or spun (with spinning head). It has a 2.5mm graded CAC aggregate. Available in 20kg or bulk bags. Great for microbiologically Induced Corrosion (or MIC) protection along with impressive abrasion resistance. Unlike the alternatives GGVSV uses 50% CAC aggregate and not 40%. This not only improves corrosion resistance but also helps with shrinkage and heat generation.
Vesuvius, Our Joint Venture Partner, was founded in 1916 as the Vesuvius Crucible Company in Pittsburgh, USA. In Australia, Vesuvius has been operational for over 30 years, establishing a significant presence in the region. It’s CAC manufacturing experience is ideally suited for making CAC mortars and shotcrete for the Wastewater industry.
Why is GoonaGuard VSV different? Less Shrinkage. With a better particle size distribution and shrinkage compensation built in. More chance of success on those larger projects. With some of the most advanced laser shrinkage measuring equipment in the country we can see what others can’t or will not admit. Our Experience makes a better Calcium Aluminate Based Product.
Spinning head application was introduced by Cemspec’s owner in Australia over a decade ago as a way to remotely apply a CAC coating in less time with improved worker safety. It is extremely useful in rehabilitating manholes or shafts that have collapsed or may collapse with minimal risk.
GoonaGuard
Cemspec started development of this technology in 2010 as a result of a request from the wastewater industry. Originally a well-known consultant made the suggestion. Positive interest from some of the Authorities and GoonaGuard evolved. So, we were patient and waited and now we have the references and testing to confidently recommend these products for new and corroded sewer structures.
It ticks all the boxes to get a job completed in the least possible time with the lowest chance of defects and you don’t need to put it on at 25mm thick. This is CAC (Calcium Aluminate) protection on steroids. Improved bonding and reduced preparation time (Does not need the high levels of surface profile needed for regular CAC mortars). No special curing (most CAC shotcretes need a lot of curing). No massive shrinkage. Can be applied with just about anything. The acid resistance is improved (we have GoonaGuard in pH=1 Sulfuric acid since 2011).
GoonaGuard is a Polymer Modified Calcium Aluminate/Geopolymer Hybrid designed to stick to most surface found in Australian sewers networks unlike every other CAC mortar. It is resistant to both Fungi and Bacteria routinely found around the country but is also acid resistant. This unique product self-cures and requires far less preparation than other CAC products and is ideally suited for new structures and remote application. It is highly flexible, and we recommend using it at a lower rate than specified by our competition. Our special blend of additives contains biocides resistant to fungi and Bacteria (like Thiobacillus strains). The Calcium Aluminate is resistant only to the bacteria. Using locally sourced aggregates with high Neutralisation capacity and Pozzolanic aggregates (recycled waste material) help longevity and the environment. GoonaGuard is also silica free.
Snotcrete
It turns out that if you use this funny sounding Silica Free Shotcrete to repair heavily corroded concrete it not only saves you money and your workers health, but it also has better corrosion resistance than regular OPC and sand shotcretes/gunites used on most jobsites in the sewer industry for rehabilitating heavily corroded structures.
This optimised shrinkage reduced mix can be wet or dry sprayed.
When working in confined spaces usually underground, even with all the PPE anything we can do to help out the people who apply these products the better. Crystaline silica has the potential to kill our friends and colleagues and does. Meets or exceeds most standards for similar sand and cement-based products. Ask us for a data sheet.
Precast and Cast In-situ CAC Concrete Structures
Want the ultimate in wastewater longevity and don’t want the hassle of coating, talk to us about precast manholes and wet wells or anything else you need made. We can also help with filling your formwork at your project on site. If you have a highly corrosive environment we have the solution. Our partner, Vesuvius Australia can manufacture a CAC concrete structure that will outlast time. Nothing to prepare de-bond or crack, this revolutionary mix self-places and is designed to fill efficiently even around large amounts of reinforcement. You can still coat it if you want to, and we can even help with preparation. Available in full CAC or with locally sourced more sustainable aggregate (not just any old gravel) at a lower price point.
Contact Our Experts
email us sales@cemspec.au
Call us +612 4776 2261
