Cork forests

Portugal is not only known for good wine and beautiful beaches, it is also the largest producer of cork, more than 50% of the world supply comes from this country, before Spain, Morocco and Algeria.

Map of the location of montado © APCOR

Natural cork originates from of the bark of the cork oak tree (Quercus Suber), which is indigenous to the Mediterranean region and northern Africa. The first harvest of a tree can be made after approximately 25 years and the bark renews itself naturally every 9 to 12 years. The cork oak forests in Portugal, called Montados are an important contribution to the biodiversity and balance in the ecosystem. The cork is present throughout the country, but especially in the Algarve and the Alentejo plains, and occupies 22% of the country’s forest area.

It is important to preserve these forests, because it is home to a number of mammals, reptiles, birds as well as the Iberian lynx, the world’s most endangered feline species. The montados are part of the Portuguese cultural heritage and contribute to the regional identity.

Properties and uses

Cork has some remarkable qualities and can be used for many different purposes, it is even applied in space as thermal insulator for space shuttles. It is light, durable, elastic, waterproof, fire retardant and has great insulation properties. Furthermore, it is 100% reusable. The structure is composed out of tiny gas-filled cells, creating a huge disproportion between the volume and the weight of the material, more than half of its volume is air.

These properties make cork incredibly useful as a building material, whether as flooring, insulation sheets or surface finish. The cork can have different shapes: insulation panels, coatings flooring, cork stoppers, composite agglomerates, raw material. 

If the material is used raw and 100% natural (if the process is free from chemical substances), it can provide an ecological alternative to conventional solutions, not least because of the barks ability to absorb CO2 during the regeneration process. Regularly harvested cork trees store 3 to 5 times more CO2 than those left unharvested.

THE PRODUCTION PROCESS OF CORK INSULATION

Working mainly on architectural projects in the North of Portugal and looking for a local material to integrate a vernacular approach, we were interested in the potential use of cork in construction.

We recently had the opportunity to use this wonderful material in two important projects and with different applications. In this article, we will describe the cork applications we tested and the methodology we used.

Like all our research, we paid attention to have the most sustainable applications with: relatively low cost, simple process and possibility to re-use the cork panels.

ADVANTAGES OF CORK INSULATION100% natural and fully recyclableExcellent thermal and acoustic insulationEasy to apply ( However, cork is fragile)Mechanical stabilityGreat behavior in large temp. range (-180ºC to +120ºC)CO2 sink (Carbon Negative)

INSULATION WALLS AND ROOFS WITH CORKS

The walls

Currently, we are finishing the renovation of a modest house for a family as a part of our Post-Graduation in Sustainable Architecture, in partnership with the municipality of Esposende.

In order to improve ceiling height and spatial quality, the roof was taken off and made new. We used the opportunity to insulate the new roof and built an exterior insulation system on the walls that had none. Like many buildings in Portugal, the Esposende house did not have any insulation .

The challenge was to find an economic and ecological solution to improve this. In the case of the rehabilitation, we faced a series of challenges:

The walls were far from being anything close to straight.We wanted to avoid the glues and mortars that are very often used in cork solutions in architecture (like in the ETICS system).

 Aerial view of the wall insulation system

So we used this cork insulation system:

1. Regularize the walls a bit, enough to limit protuberances from the wall from the line we aspired to follow.

2. Setup vertical supports on the wall, starting from the edges, following three horizontal thread lines, in order to transform a twisted wall into a straight support for our system. To protect the wood, we have applied a mix of natural oils (Read more about natural wood protection in this article)and have placed 5 cm stone wedges under the wood to avoid any contact with the floor and prevent it from rotting. Between each of these posts will come the 5 cm layer of cork.

3. Cover the walls with a first layer (1 cm) of cork, below our vertical supports fixing them with screws and wall plugs directly in the wall. A thin board is better to fit the shape of the walls without leaving empty spaces. This layer is thought to prevent thermal bridges between the 5cm layer of corks coming next. For this reason, the two layers should overlap in a tile fashion.

4. Superpose another cork panel of 5 cm on the first board and between the vertical battens. Making sure to have continuous overlap between the two layers. 

5. Fix horizontal structure on the vertical ones every 40-50cm from each other to hold the cork panels (5cm). These horizontal support will allow a wedge to sit between themselves and the 5cm cork boards, to secure the ventilation of the system and pressure the cork boards together and bear the board and batten system.

6. Set up the board and batten system on top of the horizontal structure set up in point. Depending on the wood you’re using, avoid putting two screws horizontally on the boards to avoid cracking. The boards should be free of movement and have at most one or two nail/screws set up on the vertical plane. The battens are the one pressuring the boards in place.

The roof

For the roof, we optimized the use of material to ensure the most sustainable application, as with the walls. Thus, we only used four layers: corkpanels, vapour barrier, wood and finally roof tiles. We used a corkboard of 8cm with overlapping joints to secure the potential thermal bridges. The cork boards used for the roof are overlapping to avoid thermal bridges. From the original 1000*500*40mm boards, the manufacturer cuts out 40mm on two perpendicular sides to allow the overlap. 

We decided to follow the sarking technique. The sarking method allows us to have a continuous and homogeneous insulation, without thermal bridges due to the frame.

And internally we benefit from the timber structure that can be seen inside the house!

Roof insulation system

Here are the different steps: 

Lay the cork board directly on the rafters. We used very thick cork panels to avoid using OSB as a roof support. These panels made of sheets of resinous wood assembled by a synthetic resin have the defect of not being very breathable. Cover the cork panels with a vapor barrier, this material is used for waterproofing to prevent interstitial condensation of the roof and finally to allow eventual humidity to go out. Grid the roof with vertical and horizontal battens. They will serve as a support for the tiles and will allow a complete ventilation of the roof. Set up the tiles.

GREEN ROOF WOTH INSULATIVE CORKBOARD WITH INTEGRATED DRAINAGE SYSTEM

We decided to use cork for another architecture project last year, a sustainable green roof. A vegetal roof of 140 square meters covering all the top of the workshop. In this article, we will only explain why and how we used the cork, but if you want to learn step by step how to build a green roof, we advise you to watch this video. 

We used cork for a triple goal: insulation, drainage and water retention, in partnership with Neoturf, who investigated this possibility and designed the board. The grid on the top side of the board was meticulously designed to allow for a high flow of water drainage. It is necessary for a roof to withstand frequent torrential dumpers and by using this system, we negate the need for synthetic insulation and plastic drainage cups.

These cork boards provide insulation with a thermal efficiency of 0,038 à 0,040 W/mK* on average, which is comparable with material with synthetic sources such as expanded polystyrene.

On the top, to protect the cork from the plant’s roots and substrate a geotextile is added to prevent silt and other particles from the substrate from clogging the grid drainage system within the cork. Activated clay balls surround the borders of the walls, windows, and wooden barriers, and provide additional drainage and fire protection.

The post BUILDING WITH CORK appeared first on Critical Concrete.

After three years of research, design and construction, our 130 square meter roof is finally finished! 

We are happy to share with you an overview of all the steps we went through, the sustainable technologies we integrated into this project, and the impact we think green roofs can have on our urban landscapes. 

Watch the video below for an explainer of the process of constructing our ecological green roof: 

This journey started three years ago with the demolition of the old roof and replacement with a glulam structure. Along the way we integrated several sustainable technologies that we have documented with articles and videos. For instance, we used recycled tyres for the foundations of our wooden wall structure and protected the exterior timber facade using our charring technique inspired in the traditional japanese process of Yakisugi. 

For more information about these researches, check our previous articles here.

CHARRING STATION

TYRE FOUNDATION

Green roofs are often proposed as a solution to the lack of green space in urban environments or as a way of slowing down the flow of water. But do conventional green roofs actually deliver on these claims? Our research of modern green roofs found that the materials used in construction often do not align with the sustainability ethos that a green roof proclaims. We sought to find alternatives to plastic filters, insulation, and drainage systems: the materials that typically make up the layers of a green roof. In our mission to adopt low-tech, sustainable architecture and construction techniques we wanted to reduce material consumption and also make it as easy to replicate and apply in other situations as possible.

Our green roof layers

Green Roof detail

EPDM

Laying EPDM around rooflights

EPDM Silicone

We needed a waterproof layer to cover the OSB roof layer and protect from water ingress. We chose EPDM, a synthetic rubber, due to its availability and long life span. 

Geotextile

To protect the cork from the plant roots and the substrate a geotextile layer is needed. This prevents silt and other fine particles from clogging the grid drainage system within the cork. Geotextiles are semi permeable fabrics that help separate soil layers but permit the passage of fluids. 

Irrigation System

For the climate we enjoy here in Porto an irrigation system is definitely not necessary. However in order to control the parameters of Neoturf’s experiment a system was installed. In the future we will build a rainwater harvesting system that will allow us to store and re-use rainwater for non potable purposes. Watch this space!

Cork Insulation

Cork grid

Laying the cork panels

The most cutting edge element of this design is the inclusion of cork insulation, thanks to a partnership with Neoturf, who conducted the research about this design. This is the first time this design and technology has been implemented on a green roof of this size so we are very excited and hopeful for the results. The expanded cork is a by-product of the industrial process for manufacturing wine corks and is being increasingly used in construction. We explain more about this carbon negative wonder material in a full article here. 

Cork is a carbon negative material as the trees it is harvested from absorb CO2 from the atmosphere as they grow. These cork boards provide insulation – with the thermal efficiency of Lambda 0.038-0.040 watts per meter kelvin or R3.6/inch.In cold months this is comparable to synthetic materials such as expanded polystyrene during warm weather synthetic insulation performs very poorly due to having low thermal mass [1].  Additionally, in order to allow water to drain a grid was pre-cut into the panels: vital to withstand Porto’s frequent downpours. By using this design and material we negate the need for synthetic insulation, plastic drainage cups, and other plastic liners. 

Substrates

The second experimental aspect of our green roof is being investigated in partnership with Neoturf, who specialise in landscape design and nature based solutions. The soil that is used on green roofs cannot be composed of simply hummus. It requires other gravels or materials that reduce compaction and promote effective drainage. Neoturf are investigating how well 3 different substrates that use recycled construction waste perform in contrast to the commercially available alternative. Should this research prove successful they will promote the widespread use of recycled waste as substrate across the industry. Over the next two years they will monitor the progress of the plants growing on our roof. 

Interview with Paolo Palha from Neoturf

Check out an in-depth interview with Paolo Palha, researcher and engineer from Neoturf, that gives us insights into the significance of his research and what they are expecting to find in the next couple of years, monitoring the plants’ growth:

Conclusion

This green roof represents three years of hard work, prototype development, and teamwork. Countless hands have helped repair walls, build structure, haul earth and the thousands of other tasks needed to realise this ambitious project. We send huge love and thanks to everyone who has helped in any way. This is a major milestone for us and we are excited to see our plants grow healthy and strong. Neoturf will continue with this research over the next two years, after which we can adapt the roof to grow our own food and reach a higher level of self-sustainability.

Are you interested in implementing an ecological green roof in your project? Critical Concrete can provide advice, design and construction services for the whole process: including structure, procurement and material sourcing. Contact our studio today!

Interested in using this technology in your project?

Critical Studio can help!

Learn More!

We need your support to continue researching and developing ecological, low tech solutions. Check out our patreon to see what perks we offer in return for helping us on our sustainable mission.

The post How to make green roofs really green? first appeared on Critical Concrete.
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Researching new methods of wood protection are of key importance for the work we do here at Critical Concrete. Wood is the primary material we use to build and renovate houses; from the structure, to the cladding, and the furniture. Priorities of our wood protection solutions include; relatively low-cost, accessible materials, simple recipes. Prioritising these aspects means it is easy to scale up for large projects. 

Tricoil

For our renovation project in Esposende, we rebuilt the roof with a wooden structure, so it was essential to protect the wood for the longevity of the building. With the cladding substructure, window lintel, and furniture we had a lot of wood to treat. Through research of various recipes we came up with a recipe and method which fit the requirements we had. 

TRICOIL (Turpentine/Tung Raw Linseed I Coconut OIL or 3 oil) is a blend of three different oils which gives protection from parasites and environmental conditions. Linseed oil, Tung oil, and Coconut oil are blended together using turpentine as a solvent to combine the oils and allow for deeper penetration of tricoil into the wood. The original recipe and method we based this upon can be found here [1]. 

Tung oil has been used by the Chinese for hundreds of years to protect wooden boats. It is derived from pressing the nuts of the Tung tree. It has anti-termitic properties and offers durable waterproofing. 

Raw Linseed oil, obtained from pressing flax seeds, creates a water repellent barrier on the wood.

Coconut oil, rich in fatty acids, nourishes and protects the wood. 

Turpentine, a solvent derived from tree resin, thins and blends the oils for easy application to the wood. 

Method

Ratio of ingredients for TRICOIL

Heat a large pot of water to 50°C to act as a bain-marie. Place a jar of coconut oil and turpentine into the bain-marie and cook until this mixture has also reached 50°C, stir often. If you have a big enough pot, you can do the same with the linseed oil and tung oil together in one jar, placed in the bain-marie. Once the mixtures have reached the temperature, mix them together.
The Tricoil is now ready to be applied on clean, sanded wood. Apply to the wood once per day for 3-4 days and dry in an open space. 

Burning Station

Since discovering the wonders of Yakisugi, it has become a firm favourite as a method of protecting wood in many of our projects. Our first article in wood protection dives into the science of the method and the properties of charred wood. 

After a fair few projects using our brick burning station at CC HQ, we enlisted it for charring wood for the cladding of the Esposende house. Around a half ton of bricks were put in the van and rebuilt on the street. After so many uses at such high temperatures the normal bricks and even special fire-bricks began to crack and posed a risk of collapse while using the stove. Thus we decided to design a new, super-portable, efficient charring station. 

Blueprint of the new charring station

The body of the charring station consists of an old oil drum, an inlet for passing the wood to be treated through, a feeder for fuel, and a hole to attach a chimney. It mimics the previous charring station with the L shape encouraging an upward draft. The feeder is made of an old fire extinguisher welded on with extra metal for support. 

With the use of two rollers, 1 person can manage the charring station themselves. If the fire is burning well and frequently stocked, it is possible to char a 3m 30x3cm board in 10-15 minutes for both sides. 

The efficiency and speed of this burning station allowed us to burn all the wood for the board and batten cladding of the house in Esposende. Furthermore, this higher degree of flame control allowed us to achieve a uniform result for the boards to not warp and lose their integrity. 

For improvements of the burning station we would advise a metal plate on the lip of the openings for the board to rest on – otherwise it can mark the board. Additionally, a way to adjust the opening for different sizes of boards would increase the efficiency by reducing excess draft. 

Top Tips

Have an ample supply of fuel available to keep the fire well stocked and at a medium-high flame.If the flame is burning too high it is better to do a few quick passes to avoid over-charring the wood which can result in warping.Apply raw linseed oil after charring to compensate for loss of moisture and flexibility.If the wood does warp and you are using it for board and batten cladding, mount the board with the bend curving away from the wall to reduce pressure and prevent cracking. 

There are a few drawbacks of this method and these should be considered before employing this technique in your own projects. One is the time intensive nature of the process. The burning station was fired up most days of the 6 weeks of Esposende workshop. This works if there are many hands available to take on the relatively low-skill task and take turns amongst each other. However it may prove tiresome for a self-build project. The second drawback is the issue of smoke. At Critical Concrete HQ we have neighbours in close proximity, requiring us to build an extra tall chimney to prevent smoking out the neighbours. Having ample space is also a factor to consider. The actual working site of Esposende was relatively small, however, we were lucky to be able to use the quiet street, much to the amusement of the neighbours! Looking to our next renovation project we will need to contain construction activities as much as possible as the street is very narrow with no pavement. For situations when these drawbacks are apparent we endeavour to find more suitable solutions. 

New burning station

Yakisugi cladding on wooden substructure treated with TRICOIL

Swedish Paint / Flour Paint

Filling the requirements of cheap, scalable, non-toxic and accessible ingredients, Swedish Paint is an excellent choice. Swedish paint has long been used as the primary choice for wood protection in many Nordic countries. It can endure the harsh climate while offering an appealing aesthetic. 

Swedish Paint can last for up to a decade before a new application is needed.
Photo by Anders Nord

Method

This is a new method for us and we have tried out one recipe using the materials we had available in the workshop [2].

For 3 litres of paint the following measurements can be used:

300g of flour3l of water600g of pigment300ml of linseed oil

For pigment, we used red clay that we had left over from making a rammed earth floor and wood ash from a local saw mill. There are many options for pigment, do some research and see what is available in your local area. 

This is the very beginning of our research with Swedish paint so there will be more information to come in the future as we experiment with different recipes and ingredients. We will leave these samples outside to see how they withstand the weather.

Paint samples using wood ash and clay

References

[1] ​​https://www.artamin.it/impregnante-ad-olio-fatto-in-casa/

[2] https://engelleben-free-fr.translate.goog/index.php/recette-de-la-peinture-a-la-farine-protection-des-bois-exterieurs?_x_tr_sl=auto&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=ajax,elem&_x_tr_sch=http

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Lately, there’s been an increase in interest over the well-being of coral reefs. These marine habitats represent an estimated $2.7 trillion in ecosystem service value and support around 25% of all marine life after all. But we have already lost 50% of the world’s reefs at this point. And there appears to have been no specific global funding to help develop the protection and restoration of these reefs in the past.

Recognizing this, a coalition of partners from the 75th session of the United Nations General Assembly created the Global Fund for Coral Reefs. With this fund, they hope to raise and invest $500 million (USD) to support programs that will increase the resilience of coral reefs.

That means you may soon see more construction requests for artificial reefs. These sorts of reefs are manufactured constructs designed to promote the growth of coral reefs and provide marine life with shelter. It’s a great way to secure a profitable tender and give back to the environment all at the same time.

But if you do decide to take on an artificial reef project, what can you expect?

You May See a Wide Variety of Structural Requests

Over the years, the innovation for building artificial reefs has only increased. People from all over the world have their own ideas on how to build reefs effectively. So when you do encounter such a project, you might find some unique structural requests. Here are just some of the more well-known ones you might end up with.

They May Be Complex Like a Habitat Skirt

If you win a bid for an artificial reef construction project from a governmental authority, your work may be fairly large and complex.

For instance, back in 2008, the Vancouver Convention Centre used governmental funds to include a habitat skirt worth $8.3 million. The first of its kind at the time, this project used 362 precast concrete slats. They were fit into 76 frames and arranged to look like a large five-tiered staircase. That extended the center’s shoreline by 477 m (1,564.96 ft) and added 6,122 m2 (65,896.66 ft2) of marine habitat surface area.

That is no easy feat for a project that had never been done before! As one of the University of British Columbia’s blogs notes, this amount of space is equivalent to “the length of five Canadian football fields and the floor space of the entire White House.”

It’s also not the only government project thinking big. Further south, down in the United States of America (USA), in San Diego, the port there has started to install a sea wall. Designed to protect the edges of Harbor Island, the wall is expected to help restore the island’s marine ecosystem.

It makes use of a structure that consists of the Coastalock system, which interlocks hollow concrete units to create habitats for oysters, sea stars, algae, and a variety of other marine wildlife.

The port hopes to use 72 of the 3.5-tonne modules of this system to replace the island’s current riprap.

With those two projects in mind, you can see that certain artificial reef projects will involve a decent amount of construction material, some intricate design input, and a keen contractor eye to keep everything working smoothly.

Or They May Be a Smaller Affair Using Reef Balls or Cubes

Not every artificial reef project is so extensive of course. There are plenty around the world that go to organizations like the Reef Ball Foundation and ARC Marine to install concrete structures in waters. These structures may be circular or more cube-like in shape, and they can range in size. Some may be as small as 0.3 m (1 ft) or so or as big as 1.5 m (5 ft) or more. In either case, the structures come with holes and various surface textures to offer marine wildlife places to rest and hide from predators that still look and feel like natural reefs.

They aren’t always interlocked and don’t need any additional design work. So it’s easier for people to order these structures from the organizations making them or from contractors for these organizations and have either group deploy the structures into the water.

It also makes it a less complex project on your end if you win a contracting tender for an organization that already handles this sort of work.

It May Even Involve Just Deploying Materials in a Specific Part of a Marine Area

Sometimes building artificial reefs is all about the materials and nothing else. In some cases, that might mean placing materials like defunct ships, oil rigs, or some other old, large structure into open waters.

In other cases, it might mean doing the same but with defunct subway cars! Running with that last idea, the State of Delaware in the USA has been pushing old New York City Redbird subway train cars into the open waters off the coast of Slaughter Beach since 1996. However, to make sure these cars are marine-friendly, they strip them of any glass, seats, signs, wheels, and petroleum products before dumping them. That way, water can flow in and out of the old vehicles, allowing larvae from sea invertebrates to safely drift in and gain shelter, which in turn, lets them flourish and feed other marine animals.

An even simpler version of this project that you might encounter could be a request to place concrete pipes or steel beams on the ocean floor. For instance, further south from Delaware, in Pinellas County, Florida, such projects have helped to create around 42 reefs.

These Requests Can’t Just Be Fulfilled with Any Material, However

While some projects will already have a specific material in mind like those using the reef balls or reef cubes, there will be others with more leeway. And when that happens, you’ll need to carefully consider what material you use.

Think of it as building a home of sorts. You wouldn’t just use or reuse any old material for a person’s home. It could end up being structurally unsound or even toxic for the person who chooses to live there.

The same can be said for building artificial reefs. If you choose to build reefs by reusing waste like old tires or polyvinyl chloride, you’ll soon discover that neither material is the right kind for marine wildlife to call home. They’re usually too small, for one. So organisms needed to create reefs can’t grow on them. And they’re also very unstable. The waves can carry them to any part of the ocean floor easily, which is not appealing to marine wildlife as reefs are meant to be naturally anchored to the seabed. What’s worse though is that they can both release toxic chemicals, transforming their potential to be homes into a danger zone for any aquatic creature nearby.

So, what can you use instead?

Concrete Is Often the Preferred Material for Building Artificial Reefs

You might have guessed it already considering how often previous projects have used it already. But concrete really is one of the more preferred materials for building artificial reefs. And there are a number of reasons why that’s the case.

According to the New Heaven Reef Conservation Program, some of those reasons have everything to do with the composition and versatility of concrete.

Much like reefs, the composition of concrete makes use of the chemical compound calcium carbonate. Reefs get it naturally through coralline red algae, which form a calcareous skeleton that supports coral reefs by cementing them together. Meanwhile, concrete often gets the compound through common building materials like limestone. But regardless of how they get the compound, that makes concrete at least seem more natural to marine wildlife.

That’s not all that gives its composition such an appeal. Concrete is also innately strong and heavy enough to remain anchored at the bottom of any waters it’s placed in and lasts for a long time, giving marine wildlife a secure shelter for protection or habitation.

But what about concrete versatility?

Well, because concrete can be constructed into almost any shape and size, it gives you an opportunity to give an artificial reef any number of nooks and crannies that fishes and other aquatic wildlife like to hide in.

However, There Are a Few Other Materials You Could Work With

With that said, concrete isn’t the only material that people have gone for when building artificial reefs. They have also gone with the following materials using unique methods:

Electrified steelUsing biorock technology, ecologists in Indonesia have been able to form artificial reefs with electrically charged steel structures. Using a low-voltage current to charge the steel, the ecologists create an interaction between the electricity and the minerals in the seawater. That reaction causes limestone to grow on the charged steel. That growth eventually solidifies, forming reefs much quicker than they naturally would otherwise. This method has also shown to heal injured coral up to 20 times faster than other methods.

Steel spiders Even without electricity, steel remains a good material for building artificial reefs. For instance, people off the coast of an Indonesian island have been attaching parts of coral reefs to rust-protected reinforcing steel structures known as steel spiders. Over time, this process increased the amount of coral on the steel spiders by over 60%. At least 42 different coral species were growing on the steel spiders because of this. And in the rubble surrounding the steel spiders, people found at least 58 species.

Glass bottles in concrete While this method still uses concrete, the main focus is the glass bottles embedded in the concrete. As the concrete keeps the glass bottles anchored securely, the bottles themselves act as a way to transplant broken or nursery corals to attract marine life to the area and eventually create a reef and feeding hub for fish.

If You Do Go with Concrete, Consider Increasing Its Durability

Con-Fume One major artificial reef organization in the USA, the Reef Ball Foundation, requires silica fume in the specs for their artificial reefs. So if you want to follow their design as a blueprint for your own artificial reef, you may want to apply our Con-Fume solution. It is a silica fume product made from pozzolanic material to produce high-performance concrete. It comes in ready-mix bags and meets ASTM and CSA standards for silica fume.

Hard-Cem If you happen to be placing your artificial reef project in waters with swift currents, you may want to add Hard-Cem to your concrete mix. With fast-flowing water, there’s a higher chance for debris to bump up against your reef structure, gradually eroding away its surface and even potentially causing cracks. That surface will likely weaken after some time, leaving it vulnerable to losing aggregate and cement binders to the fast-moving water. But with Hard-Cem, this possibility becomes less likely. As an integral hardener, Hard-Cem increases the abrasion and erosion resistance of concrete and doubles concrete wear life even under harsh conditions. So it is capable of giving your artificial reef the durability it needs to withstand the abrasive and erosive forces in the water.

Krystol Internal Membrane

(KIM Another issue that can threaten your artificial reef’s longevity is a sulfate attack. Sometimes caused by industrial water pollution or seawater, a sulfate attack can chemically change the reef’s cement, weakening its bond with the surrounding aggregate. That can then cause extensive cracking and wear, ruining the structural integrity of your reef. Luckily, KIM can safeguard your reef from such a situation. Using Krystol technology, it enables your concrete to react chemically to water, forming needle-shaped crystals that fill up its capillaries and micro-cracks. That ensures the sulfate in the water cannot get through your concrete and damage its structure. KIM was also one of the top-performing products at preventing the corrosion of steel reinforcement during a 10-year study in a marine environment by the University of Hawaii. Moreover, KIM is also NSF-certified as safe for potable water and has the Singapore Green Label, proving that it is non-toxic.

You’ll Soon Have an Artificial Reef Perfect for Clients and Marine Life

Knowing what to expect and what tools to consider now, you’ll be ready to create a marine-friendly artificial reef of your own in the future. Just keep in mind the potential scope, materials, and obstacles you might encounter, and you’ll have an artificial reef up in no time.

The post Building Artificial Reefs: What to Expect appeared first on Kryton.

Treating about 80% of San Francisco’s water since 1952, the Southeast Treatment Plant has been a critical structure for sanitizing the wastewater of San Francisco. However, the plant has been around for years, and now, many of its facilities need an upgrade.

Knowing this, the San Francisco Public Utilities Commission has started modernizing the plant. Part of this transformation includes replacing the treatment plant’s headworks facility with a new one. That will ensure the treatment plant will be able to more effectively remove debris and grit from the water while meeting the current seismic standards.

To construct this more modern headworks facility, the San Francisco Public Utilities Commission has collaborated in a joint venture with The Walsh Group Ltd. and Sundt. And we are pleased to note that we are helping The Walsh Group Ltd. optimize their work in this venture with our Maturix Smart Concrete Sensors.

Our Maturix specialist, Kris Till, got to discuss this in a recent video interview that he conducted (which you can see here). And in this article, you’ll get to see that discussion along with some extra details on the topic.

Why don’t we get started by having you tell us who you are, who you work for, and what you’re building?

My name is Tanner Santo. I’m a superintendent for The Walsh Group here in San Francisco, California. We are building the new headworks for the Southeast Treatment Plant. It’s going to be up to a 300-million-gallon-per-day capacity in the wet season. We’re looking at probably a good two years of structural concrete, which will primarily be my focus.

What do you consider to be the most important factor when building a project like this?

I think one of the biggest things I look for as a superintendent is to maintain efficiency while also preserving quality. There are a lot of moving parts and challenging logistics on this project. And what we need to do is just get our crews into a rhythm.

So, why are you monitoring concrete in this project?

That’s actually a very good question. We’re doing a lot of vertical walls on this job. I think we have 300 to 400 different wall placements. And the big thing for us is that we cannot strip those forms until we reach a minimum compressive strength.

What would you have done in the past to monitor your concrete compressive strength?

So, in the past, in situations like this, we pour a wall, say on a Monday, and take a bunch of concrete cylinders. By Tuesday morning, they’re sent off to a lab. If I want early breaks to remove the formwork, I need to take extra cylinders.

The extra cylinders can be costly when you talk about hundreds of wall placements. So taking and breaking extra cylinders for every placement adds up very quickly.

What’s even more of a hassle is getting those break results. So if I put in a 30-foot-tall [9.14-meter-tall] concrete wall on a Monday, Tuesday morning, I’m waiting on a testing lab to give me early breaks back and what I need them to tell me is that the concrete has reached a minimum strength. So in that morning time when I’m waiting for a break result or for the testing lab, I have a crew of guys who are basically not being efficient. They can’t strip the formwork yet.

nd what’s your current concrete monitoring process like now?

We put a few thermocouples with the Maturix Sensors into the wall at the time of placement, and thanks to the maturity curve that we’re able to calculate with the help of CEMEX, our concrete provider, we actually get a live readout of compressive strength. If we had never run this maturity curve for these sensors or monitored the live compressive strength with the sensors, I don’t think we ever would have realized how quickly we were getting concrete strength on this job.

It gives me a lot of temperature data as well. Had those sensors not been there, we wouldn’t have realized that we are working with a relatively hot mix. We now exercise some caution with some of those thicker placements that I don’t think we ever would have previously because we just wouldn’t have known what type of internal temperatures we were getting on this job. That information alone has been a big help as far as planning and scheduling goes.

It’s even so streamlined that I have notifications set up to my cell phone. I’m not waiting on a call from a testing lab. I’m not hounding a testing lab. I actually get a ding on my phone, but on this project, it’s a bit unique. It’s actually kind of in the middle of the night or the early, early morning when it tells me that a wall has reached 1,250 psi [8.62 MPa]. That way at 7 am, when the guys show up to work, we’re not waiting on anything. We immediately get to work taking the forms off. I know the wall has reached a compressive strength where it’s safe to do so. There’s really no second-guessing anything. And that helps with the logistics of cranes and organizing manpower.

Why did you specifically choose Maturix?

What made Maturix the number one choice was just the cost-effectiveness of it. A lot of the competitors have one-time-use sensors where you’re paying up around $100 a sensor and you embed it into the concrete. In every single pour, that’s $100 down the drain whereas Maturix technology is actually better because I don’t have to go around and capture the data with Bluetooth. It’s all done over a cloud network. It’s sent directly to my phone like I mentioned. I don’t have to pay someone to go around and collect data via Bluetooth. So in reality, I’m paying less for a better product.

So it seems Maturix offers cost-effective concrete compressive strength and temperature monitoring. It also documents everything related to this. Has that helped you with quality control procedures?

Yeah, definitely. It just basically organizes all our pours. I mean, I can go back to stuff I poured a month ago and see that Maturix records the exact time of placement.

What would you tell someone who is considering Maturix?

It’s streamlined. It’s easy. As far as cost-effective, it’s not even close compared to the competitors out there with the one-time-use sensors. And the labor you save in collecting the data is also a huge cost saving as well. So we’ve just been very happy with what these sensors have provided for us here.

Thank you so much for taking the time to talk with us. We really appreciate it.

No problem. You guys are helping us out a lot on this project. We got a good thing going here, so I’m happy to help out.

*Banner photo by Pi.1415926535, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons

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Concrete is formed by mixing earth, sand, and water to form a sturdy material called concrete. The paste is mixed with cement to make the mixture that forms the durable concrete. The mixture is heated and allowed to cool to create a paste that can then be poured into molds to form the concrete.

Concrete is used in many areas for its ability to withstand force and weight. It is a cheap construction material that can be used in cities and houses as a strong, reinforced concrete material for sidewalks, driveways, footpaths, and parking lots. Concrete can also be used to form the walls of the inner part of a building. Concrete can be shaped into any shape by adding additional ingredients such as stone, glass, or steel. It is very versatile when it comes to shapes because once hardened it stays that way and is extremely durable.

When the Portland cement, sand, and water mixture cools, it becomes what is known as hardened concrete. A fine powder texture is developed on the concrete once hardened. When the temperature outside falls below freezing, the Portland cement, and sand melt and form into a liquid. This process of cooling and solidification creates a thick liquid that can be easily used to fill in holes and cracks during construction projects. When concrete cures naturally, its fine grain structure creates a smooth surface that is free from chatter and scratches.

What is concrete made of once cooled and hardened are the Portland cement and the sand. When the cement and sand are combined, it becomes what is known as reinforced concrete. Reinforced concrete has a smooth, rounded surface that is more durable than regular concrete. Once the concrete is hardened, it can be poured into moulds to form the basic outline of a building or can be shaped further to achieve more detailed designs.

There are three basic ingredients that makeup Portland cement, sand, and water. All these ingredients are mixed together with or without additives to change their chemical composition. Some of the most common additives to concrete made of Portland cement include cement acid, magnesium stearate, and calcium chloride. The additional ingredients used to modify the composition improve the durability of the final product.

As mentioned above, Portland cement, sand, and water are mixed to create a fine paste that is then used to fill in holes, cracks and forms. One of the most commonly used ingredients in the creation of concrete made with Portland cement is calcium chloride. Calcium chloride is the main component of the Portland cement mixture, and it is also one of the most effective ingredients for the purpose of reinforcing concrete. Other commonly used ingredients to create fine-grained concrete mixes include magnesium stearate and cement acid.

Other cement additives are needed to improve the properties of the material to make it stronger. When concrete is mixed with regular sand, a silicone compound that improves the surface tension of the sand is added as an ingredient. This silicone compound, which is generally water-based, adds strength to the solid sand, especially when other compounds that improve surface tension are also included in the mix. A reinforcing agent such as steel reinforcement wire is added as a third additive to the cement mixture.

A common type of additive used to increase the strength of cement is a calcium hydroxide solution. This solution is mixed with the cement to make it homogenous before it is exposed to heat or pressure during the curing process. This homogenous mixture results in the formation of tougher and stronger cement, with increased wear resistance. Other types of additives that are commonly added to Portland cement are glass rods and steel wool.