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Building the future with self-healing concrete and biocement

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After water, concrete is the most widely used substance on Earth. With applications from housing and industry to coastal defence and infrastructure, concrete and cement are at the cornerstone of life, quite literally.

Unfortunately, the construction industry also has a major environmental impact. Cement production alone generates up to 8% of global carbon emissions, more than aviation (2.5%) although less than the agriculture sector (12%), according to one report.

Innovative thinking is needed to make construction materials more sustainable, while keeping them affordable and versatile. Some in the industry are using new technologies to make concrete ultra-durable, while others are turning to biology to make sustainable biocement.

New types of sustainable concrete are key to providing the foundations for other sustainable infrastructure, such as wind farms, said Professor Liberato Ferrara, a professor of structural analysis and design at the Polytechnic University of Milan in Italy.

‘If we think of all the needs that we have now for the energy transition, I would say that we cannot do this without concrete,’ he said.

Punishing settings

He led a project called ReSHEALience, which set out to develop ultra-high-durability concrete (UHDC). Such concrete is able to withstand extreme conditions and self-heal when used for construction in punishing settings like marine environments and geothermal energy plants.

‘These environments are among the most aggressive situations that you can have for concrete structures,’ said Prof Ferrara.

The tailored recipes are what gives these concrete mixes their strength and durability, including components such as crystalline additives, alumina nanofibres and cellulose nanocrystals.

Concrete inevitably cracks during its service life, but one of the features of crystalline mixtures is that they stimulate self-healing. By reacting with water and constituents in the concrete, they form needle-shaped crystals that grow to fill the cracks. The nanofibres mixed through it add mechanical strength to the material and help to enhance its toughness, allowing it to endure extreme conditions. 

UHDC has been tested as a durable substitute for traditional wooden rafts in mussel farming, and to make parts of floating wind-turbine platforms in coastal areas. It has also been tested in the harsh conditions of a geothermal power plant, where its performance improved on traditional methods of construction.

Its use in the restoration of an old water tower in Malta demonstrates the concrete’s potential for the maintenance of heritage architecture.

Sustainable material

‘The pilots are matching expectations from all points of view,’ said Prof Ferrara. ‘We succeeded in demonstrating that UHDC is intrinsically a sustainable material. It allows the use of less material to build the same structure, so in the end the environmental footprint and economic balance is better.’

The material slashes resource use both by reducing the amount of material needed in the first place and by lasting much longer, with Prof Ferrara predicting that it may have the potential to last up to 50 years before requiring significant maintenance. 

It can be produced in a wide variety of locations for many different applications using local materials. Moreover, crushed UHDC shows promise as a recycled constituent to produce new concrete with the same mechanical performance and durability as the parent concrete.

The increasing urgency of meeting sustainability goals calls for fresh ways of looking ‘holistically’ at construction, Prof Ferrara added.

‘It’s about spreading a new way of thinking for concrete structures’ that considers the whole value chain and service life of the planned structures, he said. ‘You have to think of the structural design, the procurement of materials, and the materials’ durability and life cycle. If you do not think like that, you will always have partial information and innovation will not break through.’


Elsewhere, researchers are looking at quite different ways of innovating in the construction sector, harnessing the natural processes of living organisms.

For rail companies, the settlement of soils over time in embankments beneath railways can create serious problems and add to maintenance costs and passenger delays. 

Mechanical methods for firming up ground materials or chemical-based stabilisers are usually employed as a solution. However, these can be disruptive and costly, have environmental side-effects and generate carbon emissions.

The NOBILIS project is therefore getting bacteria to do the work, viewing the ground as a living organism rather than a nondescript mass to be moved by bulldozers.

The idea is that stronger soil, created through a process called ‘biocementation’, can reduce the need for earthworks and materials like concrete.


In the process of biocementation, the bacteria’s growth and metabolic activity are stimulated by providing them with nutrients and so-called cementing agents. The resulting enzymes produced by the bacteria catalyse reactions that ultimately form substances such as calcium carbonate, which bind the soil particles together.

The technique has been recognised as having potential in soil with larger particles, such as sandy soils, including forming beach rocks to protect against coastal erosion and for other applications in civil or environmental engineering.

However, a bigger challenge emerges with finer-grained soils like clay and peat, due to more restricted movement of bacteria, water and other substances. Undeterred, NOBILIS is seeking to explore ways to use biocementation on a wider range of soils.

Recent work in East Anglia, UK has demonstrated the possibility of biocementing peat soils. The NOBILIS project will aim to scale up this work through trials in the field, said Professor Maria Mavroulidou, a geotechnical researcher and project lead at London South Bank University (LSBU).

Paradigm shift

Prof Mavroulidou said this kind of biology-inspired approach requires new ways of thinking and faith in unfamiliar techniques.

‘To tell a practising civil engineer that you’re going to use bacteria to cement the ground raises eyebrows,’ she said, because it’s a paradigm shift for the industry.

Wilson Mwandira, an environmental engineering researcher, also at LSBU, said NOBILIS is investigating techniques to lock up carbon dioxide in the soil as biocementation occurs, as well as looking at the potential of using more indigenous bacteria in the process.

Using bacteria already present in the soil would avoid having a negative impact on organisms already in the environment, explained Mwandira. ‘If you bring new bacteria into a community, you are going to have a disruption in the system,’ he said.

The hope is that such biocementation techniques will become more widely applicable to construction work in general. ‘We’re also trying to extend the technique more generally to other geotechnical materials found in foundations under buildings and civil-engineering construction,’ said Professor Michael Gunn, a geotechnical engineer also at LSBU. ‘All construction requires some form of ground improvement.’

He thinks that it could take a number of years for the techniques to be used in a more routine way, but that it is essential such innovative methods are explored to address long-term challenges in construction.

‘A significant proportion of greenhouse gas emissions in the form of carbon dioxide is down to the construction industry,’ he said. ‘So we need to move away from the traditional processes.’

The research in this article was funded by the EU. This article was originally published in Horizon, the EU Research and Innovation Magazine.  

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UN: A divided world faces a huge number of problems

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The current session of the UN General Assembly has shown that the United States will not force the Global South to take its position in the Ukrainian conflict, writes ‘An Nahar’ from Lebanon. Developing countries refuse to condemn Russia and demand an end to hostilities, as they suffer from their consequences.

UN Secretary-General António Guterres said during his speech that humanity faces enormous challenges, from a worsening climate emergency to escalating conflicts, a global cost of living crisis, growing inequality and technological changes.

This is a huge number of problems that a divided world faces. The role of the United Nations has noticeably declined. There is intense competition between the West, led by the United States, on the one hand, and developing countries, led by China, on the other. More than ever, Beijing wants a say in international affairs commensurate with the size of the Chinese economy that has boomed over the past four decades.

The United States appears to be facing an almost impossible task of forging a global consensus on isolating Russia internationally over the situation in Ukraine. Most developing countries have a different view of the Ukrainian conflict, which has been going on for 18 months. They demand a political solution and an immediate cessation of hostilities.

Washington is trying in vain to pressure countries in the Global South to accept a Western strategy based on the idea that the problem will be solved when Russia suffers a crushing defeat in Ukraine. There are leaders in the world who strongly disagree with this approach. Brazilian President Luiz Inacio Lula da Silva, for example, accused the United States of encouraging the conflict in Ukraine. In addition, developing countries have not joined Western sanctions against Russia, despite the pressure put on them.

While Western powers are able to pay for aid to Ukraine, developing countries are suffering from continued hostilities and cannot bear the costs of the conflict. The longer the fighting goes on, the more states in the Global South insist on a ceasefire.

Developing countries are increasingly concerned about pressing issues such as food security, climate change, inequality and the debt crisis. It won’t be long before the consequences of the collapse of the Black Sea grain deal between Russia and Ukraine begin to show in poor countries.

Although the regular session of the UN General Assembly allows for discussion of pressing global problems, disagreements have arisen among participants regarding how to solve them.

The division of countries into international blocs competing with each other has led to the fact that the United Nations has practically lost its global significance and demonstrated ineffectiveness in resolving international conflicts.

The more tensions between states escalate, the weaker the role of the United Nations becomes.

The intensity of global competition is preventing the United Nations from fulfilling the mission for which it created.

The world divided into opposing camps, each of which is looking for the best way to protect its national interests. It is not easy to find a way to salvation or get out of a dead end, ‘An Nahar’ writes.

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India’s Canadian riddle

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The timing of the Canadian assault on the Indian foreign and security policy establishment over the killing of Hardeep Singh Nijjar is not in doubt, stresses M.K. Bhadrakumar, Indian Ambassador and prominent international observer.

It surged in the aftermath of the G20 summit, which witnessed a crushing diplomatic defeat for the US in front of the world community, where the host country India navigated skilfully to scuttle any negative reference to Russia in the event’s final document.

The Nijjar affair can be metaphorically called the grapes of wrath. The liberal western world so far granted Modi government a free passage through their rules-based order. India could preach, but wasn’t accountable for its own practice. All good things come to an end.

Canada has a record of acting as a surrogate of the US. As regards Nijjar file, a Canadian official familiar with the matter told Associated Press that Prime Minister Justin Trudeau’s allegation against Modi government was based on surveillance of Indian diplomats in Canada, including intelligence provided by a “major ally” who is a member of the infamous Five Eyes, the secretive intelligence network of Anglo-Saxon countries — Australia, Britain, Canada, New Zealand and the US.

Interestingly, Britain scrambled to distance itself from Trudeau’s tirade, while a Canadian source told Reuters that Canberra and Washington collaborated “very closely” to examine evidence indicating potential Indian involvement in Nijjar’s killing.

Trudeau spoke in the Canadian parliament after consultations with President Biden, and the White House reaction on the same day was highly supportive. The White House National Security Council spokesperson Adrienne Watson said, “We are deeply concerned about the allegations referenced by Prime Minister Trudeau. We remain in regular contact with our Canadian partners. It is critical that Canada’s investigation proceed and the perpetrators be brought to justice.”

Watson works under NSA Jake Sullivan who reports directly to Biden. It is unlikely that Sullivan made this a personal issue with the Indian security establishment. Simply put, the buck stops at the Oval Office.

Indeed, after Watson’s initial remark, the White House quickly switched to megaphone diplomacy with its highflying strategic communications chief John Kirby, a retired rear admiral, confirming for record that Biden is “mindful of the serious allegations” by Trudeau “and they are very serious… and we support Canada’s efforts to investigate this. We believe a fully transparent, comprehensive investigation is the right approach so that we can all know exactly what happened, and of course we encourage India to cooperate with that.”

Such gratuitous lecturing is sheer hypocrisy by a country that freely resorts to assassination as a tool in its foreign policy. Who killed Qassem Soleimani?

Alas, in the face of this bullying, Delhi’s reaction has been pusillanimous, to say the least — as if it is stone deaf and couldn’t hear what the White House officials were saying.  

One would like to believe that India, with high values in global governance and deep respect for national sovereignty — apart from being the flag carrier of the concept of ‘Vasudhaiva Kutumbakam’ (‘The World is One Family’) — would never descend to such a heinous level as to practice murder in its statecraft.

The Indian government should strategise through its present predicament. After all, as a key member of the western alliance and a close ally of the US, Canada plays an important role for the US in establishing a so-called rules-based international order and promoting the Indo-Pacific Strategy. And “rules-based order” and Indo-Pacific Strategy are Indian mantras too.

Biden himself may come under cloud very soon and be battling for his political career. Inviting him to be the chief guest at the Republic Day with an additional frill thrown in by way of a QUAD summit to placate him is pointless. Once the Canadian investigation runs its course, Ottawa may put on the public domain further accusations passing for “evidence” — and that could happen at some point closer to our general election. All in all, the big question is, what is it that the US is really upto.

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Assad-Xi Jinping meeting: China-Syria strategic partnership

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Image source: Xinhua

Chinese President Xi Jinping and Syrian President Bashar al-Assad on Friday jointly announced the establishment of a China-Syria strategic partnership, Chinese Xinhua Net informs.

The two presidents met in the eastern Chinese city of Hangzhou, Zhejiang Province, ahead of the opening of the 19th Asian Games.

Syria was one of the first Arab countries that established diplomatic relations with the People’s Republic of China, and was one of the countries that co-sponsored the resolution to restore the lawful seat of the People’s Republic of China in the United Nations, Xi said.

Over the 67 years since the establishment of diplomatic relations between the two countries, the China-Syria relationship has stood the test of changes in the international situation, and their friendship has grown stronger over time, he said.

Xi noted that the establishment of the strategic partnership will be an important milestone in the history of bilateral ties.

China is willing to work with Syria to enrich their relationship and continuously advance the China-Syria strategic partnership, Xi said.

Xi emphasized that China will continue to work with Syria to firmly support each other on issues concerning the two sides’ respective core interests and major concerns, safeguard the common interests of both countries and other developing countries, and uphold international fairness and justice.

China supports Syria in opposing foreign interference, rejecting unilateralism and bullying, and safeguarding national independence, sovereignty and territorial integrity, he said.

China supports Syria in conducting reconstruction, enhancing counter-terrorism capacity building, and promoting a political settlement of the Syrian issue following the “Syrian-led, Syrian-owned” principle, Xi said.

China also supports Syria in improving its relations with other Arab countries and playing a greater role in international and regional affairs, he added.

China is willing to strengthen Belt and Road cooperation with Syria, increase the import of high-quality agricultural products from Syria, and jointly implement the Global Development Initiative, the Global Security Initiative and the Global Civilization Initiative to make active contributions to regional and global peace and development.

Assad said that in international affairs, China has always aligned itself with international fairness and justice, and upheld international law and humanitarianism, playing an important and constructive role.

Syria highly appreciates and firmly supports the Belt and Road Initiative, the Global Development Initiative, the Global Security Initiative and the Global Civilization Initiative, and will actively participate in them, Assad added.

The Syrian side thanks the Chinese government for its invaluable support to the Syrian people, firmly opposes any act of interference in China’s internal affairs, and is willing to be China’s long-term and staunch friend and partner, he said.

Assad said Syria will take the establishment of the Syria-China strategic partnership as an opportunity to strengthen bilateral friendly cooperation and step up their communication and coordination in international and regional affairs.

After the talks, the two heads of state witnessed the signing of bilateral cooperation documents in areas including Belt and Road cooperation, and economic and technological cooperation.

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