Self-healing concrete aims at turning potholes into relics of the past

How many times did you get angry or even worse, take your car to the garage for expensive repairs caused by potholes? The answer is most probably: too many times. The good news is that potholes could soon become a relic of the past due to futuristic plans to produce self-healing concrete.

Self-healing concrete

The development of self- healing concrete is also aimed at improving the durability of structures and eliminating the endless traffic jams caused by manual repairs to structures. Structures made of self-healing concrete have an inherent healing mechanism that becomes active when a crack appears, thus rendering manual crack repair completely obsolete.

Scientists are experimenting with various groundbreaking new materials to find the ideal formula for to solve this issue.

Self- healing concrete

PU precursors have shown great potential

For the efficient healing of cracked concrete, the use of encapsulated PU-based precursors has already shown great potential. So far, results have shown a good regain in mechanical behavior and liquid-tightness. In proof-of-concept tests, glass tubes were used as encapsulation material. 

However, to up-scale the technique and make it compatible with conventional concrete production and placing methods, polymeric spherical microcapsules would be more suitable. Therefore, research is ongoing to optimize the encapsulation technique. Moreover, PU-based precursors are adapted to increase the resistance of the healing agents to cyclic loading, so that also the healing of dynamic cracks can be considered.

Using sunlight to fix concrete cracks

Researchers have demonstrated a sunlight-induced, self-healing protective coating designed to fix cracks on the surface of concrete structures before they grow into larger ones that compromise structural integrity.

The new coating contains polymer microcapsules, filled with a solution that, when exposed to light, turns into a water-resistant solid. The idea is that damage to a coated concrete surface would cause the capsules to break open and release the solution, which then would fill the crack and solidify in sunlight.

Biomerization

Bacteria as healing agent

Also bacteria can be used as healing agent.  Scientists are experimenting with the groundbreaking new material, which uses special bacteria to plug gaps and cracks opened up by bad weather.

Researchers at the University of Bath, Cardiff University and the University of Cambridge created the concrete blend, which is full of bacteria hidden in tiny capsules. As soon as water seeps into a crack, the bacteria quickly burst out their cases and produce limestone, sealing the gap up before it can widen and become a pothole.

Lower CO2 emissions and 50% lower costs

The scientists believe the technique could vastly increase the life of concrete, remove the need for repairs, and reduce costs by up to 50%.

Carbon dioxide levels in the atmosphere would be lower because there would be no need to constantly replace roads. More than 7% of the world’s CO2 emissions are due to cement production.

How tall could a wooden building rise? Experts say the sky is the limit and talk skyscrapers

A nice wooden cottage with a lake view; a wooden chalet in the mountains where you could sit in front of the fireplace with a good book and watch the snow fall on the window; or a small log cabin in the woods, where you could enjoy your breakfast on the porch every morning, listening to lovely bird songs, these are the types of buildings that you most probably imagine whenever you think of wood buildings. But could you envisage working in a wooden skyscraper? Hardly.

130 years after the world’s first skyscraper- the Home Insurance Building- was built in Chicago by American engineer, William Le Baron Jenney, the construction methods and by-products associated with such large scale infrastructure has inevitably led architects and engineers to seek new ways of building taller and faster without having such a drastic impact on the environment. And that has seen them revisit the most basic building material of them all: wood.

Not any wood is suitable for such a concept though. A type of super-plywood, called cross-laminated timber (CTL) has been created to maintain the strength of high-rise constructions. This effect is achieved by gluing the layers of low-grade softwood together to create stronger timber panels. Softwood panels are usually made of cedar, Douglas fir, pine, or redwood.

Reducing the environmental impact of architecture

In his book, “The Case for Tall Wood Buildings”, Vancouver- based architect, Michael Green explains how wood will be able to absorb carbon dioxide from the atmosphere.  Unlike conventional materials like concrete, wood can be used as it is. Natural resources like coal and gas don't need to be burnt to produce it, so less carbon ends up in the air. Since it is healthier for us, and for the planet, why not make the best of it?

Timber stores 0.8t of carbon dioxide within 1 cubic meter. In comparison, the production of both concrete and steel are one-way energy intensive processes that release large amounts of carbon dioxide into the atmosphere.  A 10-storey building could absorb as much as 1,600 ton of carbon, in comparison to a concrete building’s comparatively low 600 tons, according to the Canadian architect.

Michael Green proposed 20-storey (60-metre) structures made from cross-laminated timber (CLT) panels. CLT is a durable and solid-wood material developed European technology, to replace all structural elements above ground level.

Untreated timber has the potential to rot when exposed to moisture and air over extended periods of time, but CTL buildings are designed with a rain screen façade to effectively manage moisture exposure.

Stadthaus Building- London

How long will a CTL building last for? Apparently it can last as long as a concrete or steel building. CTL has been certified for a minimum 60 year lifespan by Building Research Establishment in the UK, which is the equivalent of concrete or steel.

Moreover, wood is natural, warm (intrinsic thermal properties means lower heating and cooling costs), compatible with other materials, non allergic and healthy to inhabit and has attractive natural colors.

Stop cutting trees and beware of fire!

The benefits of wooden skyscrapers are clear for all to see.  Criticisms regarding cutting even more trees down to aid the trend have also been refuted, with there now being a use for trees already damaged. Similarly, trees can also be grown in nurseries.

But while timber advocates such as Green hope to sow the seeds of change in the minds of policymakers worldwide, building regulations still put a low-rise lid on the height of timber buildings. This is based on wood’s historic reputation as kindling for a great city fire.

Roaring fires have ravaged city streets, in London, Chicago or San Francisco, to only mention a few cities, wiping out great examples of grand architecture and razing urban history to the ground. But today’s engineered timber develops a protective charring layer that maintains structural integrity and burns very predictably, unlike steel, which warps under the intense heat.

Europe leads the way in the concept’s innovation

Until now, America’s conservative building regulations and a lack of interest from developers and their customers have meant few interesting wooden buildings have been built there. In contrast, Europe, Australia and especially Canada are embracing the emerging technologies.

Forte Building- Melbourne

So far two high- rise buildings made of wood have been erected in the world: nine-storey Stadthaus in London and the 10-storey Forte Building in Melbourne.  Also in Bergen (Norway), a 14-storey wooden building is currently under construction.

Forté, the world's tallest timber apartment building, raising 10 floors above the ground only includes 23 apartments and was built in 16 weeks.

With so much controversy around this subject we are obviously not going to see the first wooden high-rise building city in the near future. Until then you might just want to have a look at Michael Green’s video “Why we should build wooden skyscrapers”.

What if you could 3D print your dream home in one day?

What if your dream home was ready in one day (Yes, one day!) and it only cost 5.000 USD? As unbelievable as this may seem, printing homes is possible today, according to international media. This would be a breakthrough with profound implications for housing affordability and customization. It would also be nice to see concrete replaced by a more sustainable material, which would truly reduce the carbon footprint of this type of construction.

Chinese company Win Sun New Materials showed that this was possible. The company successfully printed 10 houses in one single day. The reported cost for each house printed by the Chinese company Winsun was just 5,000 USD.

Rather than printing the homes in one go, Winsun’s 3D printer creates building blocks by layering up a cement/glass mix in structural patterns. 

The diagonally reinforced print pattern leaves plenty of air gaps to act as insulation. These blocks are printed in a central factory and rapidly assembled on site.

You may want to see how this was done:

In Amsterdam, a team of architects has started construction of the 3D Print Canal House, using bio-based, renewable materials. The site is both construction site and public museum.

Canal House Amsterdam

The Canal House is a symbol of Amsterdam. When the canal belt was built 400 years ago, Amsterdam was a prime example of innovation.

“It is indeed a very interesting and revolutionizing approach to construction. I wonder however what would be the costs of operation: heating and cooling of these homes? The enormous advantage is the incredible customizability. Although an interesting use of robotics and waste materials, I believe it is important to look at all aspects of housing (energy required for operation, weight, seismic requirements, fireproofing, etc.) before decisions are made to move forward with this concept. Still - very flexible possibilities now that the machine is built and working. I will certainly look forward to seeing what they do with it next.“ says engineer Gheorge Bitca, head of OCTAGON's tendering department.

What are some of the advantages and disadvantages of 3D printing a building?

One great advantage of 3D printing over traditional building techniques (such as prefabricated concrete) is the possibilities of using a high level of detail and ornament and variation. Rather than using standardized elements, 3D printed designs can each be modified and customized to fit the user's needs and taste. It will no longer be more expensive or more labour intensive to add details to, for example, your façade and it is easy to create unique objects.

3D printing is an additive manufacturing technique. That means the process goes straight from the raw material to the final product, thus eliminating waste. There are no transport costs, as designs can simply be transferred digitally and printed locally.

In terms of disadvantages, it is obviously a huge challenge to create a building that complies with all the current building regulations. There is the question of insulation, fireproofing, wind loads, foundations, as well as the possible materials to print with (using this printer). All theseaspects are currently being researched and investigated.

Printing one house in a run, still challenging

A gigantic 3D printer, able to print whole house in a single run, from its structure to its electrical and plumbing systems has not been created yet, so the houses are printed piece by piece for the time being.

For the last seven years, Loughborough’s University researchers have been developing 3D concrete printing technology for commercial purposes. They came up with a system that is made up of a gantry and robotic arm, which they are still perfecting. This device uses very exact computer control to extrude cement-based mortar into layers and create building components that can then be joined together into a larger structure.

The researchers are certain that this technology already allows for the building of complex structures that would prove a challenge for traditional construction. In fact, their 3D concrete printer could potentially print whole sections of a building with all the electrical and plumbing spaces already in place. This would cut down on the building time considerably, even when the project is a large, multi story structure.

Stay tuned, a revolution in traditional construction is well underway!

Two landmark projects built by OCTAGON, made public debut in 2014

With lots of projects under development and new investments on the pipeline, 2014 was certainly a dynamic year for the office segment. And developers rolled the dice in favor of OCTAGON. The company made the best of the market opportunities and managed last year to deliver two major office buildings, both of them located in Bucharest: Green Court Bucharest – building B and Hermes Business Campus- building B.

How did we do it? It was not easy, but we somehow managed to master extremely tough site conditions, we put in a lot of hard work and used the latest technologies in building processes. Below are highlights from each project.

As green as it gets

What did the real estate giant Skanksa envision when they decided to develop the office complex Green Court Bucharest? Large open office spaces, easy to reach from any area of Bucharest, with lots of green elements, in order to create a healthy comfortable working environment.

Green Court Bucharest - building A

How did this concept translate into design? The project includes three office buildings stretching over 52,000 sqm, built in Bucharest’s office hub, at the crossroads of Barbu Văcărescu Blvd and Pipera Road, within five minutes walk from Aurel Vlaicu metro station. Skanska also thought of making the project as green as possible and thus implemented  “green” solutions, such as glass façade with low heat transfer, natural lighting in over  85% of the working areas, power stations for electric cars charging, bicycle parking areas and facilities such as showers and locker rooms.

OCTAGON was hired to build the infrastructure and superstructure of building A and the superstructure of building B and successfully delivered both projects in 2013 and 2104.

Building A has a GLA of 19,500 sqm, 12 floors and is 91% leased by clients such as Schneider Electric România, Orange România, LS TRAVEL RETAIL Romania. The building was acquired by real estate investor Globalworth Real Estate Investments Ltd for 44 million euro.

Building B has a total GLA of 18.000 mp, 12 floors and 3 underground parking levels, with 315 available parking spaces. The second phase of the project also features sustainable solutions to minimize the impact of the building on the environment and to significantly reduce operational costs.

Modern technologies such as energy efficient double façade, efficient lighting systems, equipped with movement and intensity sensors, were used.

Beating the odds

In 2010 Belgian developer Atenor Group decided to build their first project in Romania, right across Pipera metro station. Building a 78,000 sqm office complex in a moment when the market was on a downward path seamed, at the time, extremely ambitious. Four years later, the first of the three buildings was delivered by OCTAGON and the company is now working on building the second one.

It sure was and still is a challenging project, but so far, it has beaten the odds. Hermes Business Campus started in a moment when the entire real estate market was on a downward path and few companies were thinking of relocating or leasing spaces in large scale office schemes.

Hermes Business Campus- building B

While building the first office unit of the complex, Austrian general contract, Alpine Bau, went bankrupt and OCTAGON, which was Alpine’s subcontractor, took over the project and continued the works.

Building B covers 37,000 sqm, has eight floors above the ground plus technical floor and is fully leased.  The Embassy of Netherlands, Xerox, SNC Lavalin and Synevo IT are among the tenants of the building.

On the western façade photo voltaic cells were installed, thus ensuring 7% of the entire energy consumption for one year.

OCTAGON used 31,000 cm of concrete and 3,600 t of metal fittings for the construction of building B. Three hundred people worked on the construction site and the project was delivered in June 2014.

The office building is currently being BREEAM certified with Excellent rating on-design and post-construction, which represents the best certification a building can obtain in terms of sustainable and green features.

Watch the video here:

  

OCTAGON CONTRACTING & ENGINEERING

More information here

Tel: (+40) 21 232 39 20

Video: OCTAGON built the foundation in top- down system for Sky Tower- the tallest building in Romania

Reaching 137 m in height and counting 5 underground levels and 37 ground levels, Sky Tower is the tallest building in Romania. The building, located on Calea Floreasca is visible from any area of Bucharest. OCTAGON CONTRACTING & ENGINEERING built the foundation of Sky Tower and performed thus the deepest excavation in Romania, so far: 50 m. The infrastructure works also included the execution of diaphragm walls D 1,000, foundation barrettes D 600 and dewatering systems. OCTAGON performed the construction in top- down system of three reinforced concrete slabs, covering 4,600 sqm each. The video renders the entire execution process of the foundation works.

OCTAGON CONTRACTING & ENGINEERING

Mai multe informatii aici

Telefon: (+4) 021.232.39.20

Video: Hermes Business Campus- execution of building B

In June 2014 OCTAGON CONTRACTING & ENGINEERING delivered the first building of the office complex Hermes Business Campus (Dimitrie Pompeiu Blvd.- Bucharest). The construction of the building stretching over 36,000 sqm and counting 4B + 8 E+ Technical floor in height began in December 2010. OCTAGON is now working on the second stage of the complex- building C. Hermes Business Campus, the first project of the Belgian company Atenor Group in Romania, will have three development stages and will cover 78,000 sqm at the end.  OCTAGON won the Quality Trophy ARACO 2014 with this project. The video renders the execution stages of building B.

OCTAGON CONTRACTING & ENGINEERING

More information here

Telefon: (+4) 021.232.39.20

The Advisers/ Knight Frank: Office take- up in Bucharest up by 12% in H 1 2014. First building of Hermes Business Campus, delivered by OCTAGON, fully leased

Office take-up in Bucharest amounted to 132,000 sqm in H1 2014, up by 12% year-on-year, according to the latest survey of The Advisers/ Knight Frank. Pre- leases and relocations each accounted for 29% of leasing deals, while renewals represented another 20%. Notably, firm expansions and new market entries are on the rise- representing 22% of activity- supported by strengthening economic conditions.  The Romanian economy powered ahead in 2013, with GDP growth exceeding expectations, reaching 3.5%. Growth of approximately 2.5% is forecast for 2014. Business sentiment continues to improve, with more international firms considering Bucharest as a major outsourcing location in Central and Eastern Europe.

Green Court Bucharest- building A

Occupiers in the IT & C sector were the most active players in the first half of 2014, with telecommunication providers Vodafone and Orange signing the two largest deals. Vodafone agreed to prelease 16,000 sqm in the Bucharest One project with the option to further expand, while Orange leased 13,700 sqm in Phase one of Skanska’s Green Court, delivered by OCTAGON CONTRACTING & ENGINEERING in 2013. OCTAGON also built the superstructure of the second building of Green Court office complex, located in northern Bucharest on Gara Herastrau Street.

Another A class office development built by OCTAGON, which was fully leased, is the first building of Hermes Business Campus, stretching over 37,000 sqm and rising eight floors above the ground. The building also has 4 basements, one ground floor and one technical floor. OCTAGON has just finished building the infrastructure of the second building of the project and is now working on the structure.

Hermes Business Campus- building B

Bucharest has recently seen a rise in development activity, with a total of nine new and refurbished schemes completed in H 1 2014, providing 120,000 sqm of class A space. The development pipeline has also expanded and currently stands at 200,000 sqm; of this, 55,000 sqm is expected to cover over H2 2014.

Despite the increase in new supply, the average vacancy rate for class A and B stock fell by 6 percentage points year-on-year to 17.4%. This is largely on the back of significant lettings at completed buildings, including the recently delivered Floreasca Park, which was fully leased by The Advisers/ Knight Frank.

Over H 1 2014, headline rents across all major submarkets remained stable. While headline prime office rents are expected to remain in the range of 18- 18.5 US per sqm per month, over the second half of the year, incentives are likely to harden slightly.

Hermes Business Campus- foundation works on building C

Investment market

The first half of 2014 saw a marked increase in property investment activity, with total volumes reaching a remarkable 460 million USD. Investment volumes in 2014 already exceed those of 2013 and, with several prime assets on the  market, further major transactions are expected to be completed in the second half of the year. 2014 is on the track to surpass the total amount transacted over the last two years, potentially breaking 2010’s record of 543 million USD.

While transaction activity was dominated by domestic restructuring deals, investment demand remains robust, with both domestic and international effort focused on office and retail assets in Bucharest.

While transaction activity was dominated by domestic restructuring deals, investment demand remains robust, with both domestic and international interest largely focused on office and retail assets in Bucharest.

The largest deal in H 1 2014 saw investment fund Globalworth purchase the Upground complex in Pipera from Deutsche Bank’s RREEF for some 200 million Euro. The deal included the sale of a residential compound, as well as both BOC and BOB towers, for 110 million and 42 million Euro respectively.

While the current strong economic backdrop is attracting greater investor interest, the limited availability of prime office stock across major markets has proven to be a hindrance to activity. However, this is set to change, as Bucharest’s stock of class A buildings continues to increase, helping to improve office market conditions and offering a wide range of opportunities to international investors.

As a result, prime office yields in Bucharest have seen moderate compression over the last twelve months, hardening by 25 bps to stand at 8.00%. Sustained investment demand over the second half of the year is likely to drive prime yields below 8.00%.

OCTAGON CONTRACTING & ENGINEERING

More information HERE

Tel: (+4) 021 232 39 20