Category Architecture

What is the secret behind Roman concrete?

Researchers have solved a long-standing riddle to explain why Roman concrete is so durable.

There’s no denying that the ancient Romans were masters of engineering. They constructed vast networks of roads, ducts, ports, and buildings, whose remains have survived for two millennia. Rome’s famous Pantheon, which has the world’s largest unreinforced concrete dome, has stood the test of time for nearly 2,000 years and remains intact.

All this is in stark contrast to modern concrete structures that have crumbled after just a few decades. While researchers have spent decades trying to figure out the secrets behind this ultra-durable ancient construction material, a team from Massachusetts Institute of Technology, Harvard University, and labs in Italy and Switzerland has made some progress. Their findings were published in the journal Science Advances in January 2023.

Role of lime clasts

Close examination of these ancient samples revealed that they contain small, distinctive, bright white mineral features, recognised as a ubiquitous component of Roman concretes. Referred to as “lime clasts”, these white chunks originate from lime, another key component of the ancient concrete mix.

While these lime clasts have previously been disregarded as evidence of sloppy mixing practices or even poor-quality raw materials, this study suggests that it was these lime clasts that gave the concrete self-healing capabilities that were unrecognised so far.

Quicklime’s effect

Researchers wondered if the Romans directly used lime in its more reactive form, quicklime, rather than slaked lime (calcium oxide mixed with water). Studying the samples showed certain inclusions and clues that these would have formed at extreme temperatures. This bode well for their hypothesis as extreme temperatures are expected from exothermic reactions produced by using quicklime, as opposed to, or in addition to, the slaked lime in the mixture. The team concluded that hot-mixing played a pivotal role in the super-durable nature of the concrete.

To prove that this is the case, the team then created samples of hot-mixed concrete that incorporated both modern and ancient formulations. These were then deliberately cracked and water was made to run through the cracks.

The self-healing nature of concrete thus created meant that the cracks completely healed within two weeks due to the reaction with water and water could no longer flow. In the case of an identical slab of concrete made without quicklime, it never healed and the water kept flowing.

The success of these tests have prompted the team to try and commercialise their modified cement material. The extended lifespan of these concrete forms can help reduce the environmental impact of cement production, which currently accounts for nearly 8% of global greenhouse emissions.

Picture Credit : Google 

Which is the highest gateway in India?

Buland Darwaza, prime monument of Mughal architecture, is the highest gateway in the world. Buland Darwaza was built by the emperor Akbar in memory of his victory over Gujarat. The 15-storey-high gateway is the southern entrance to Fatehpur Sikri, which is a city, located 43 km away from Agra. It was formerly called Fatahabad, derived from the Persian word Fatah meaning victory. The city flourished as Akbar’s capital till 1585. During that year, it was abandoned because it was near the Rajputana neighbourhood with limited water resources. Subsequently, the capital was changed to Agra and Fatehpur Sikri became a ghost town.

Standing tall in the courtyard of the mosque, Buland Darwaza is a prominent monument in Fatehpur Sikri. The central face of Buland Darwaza carries an inscription that talks about Akbar’s religious tolerance and how broad-minded he was. The eastern archway of Buland Darwaza has a Persian inscription, which is a record of Akbar’s conquest of the Deccan in 1601 AD. Along with decorations in carving and inlaying of white and black marble, it has 42 approach steps and is 53.63 metres high and 35 metres wide. It has a consolidated height of about 54 metres from the ground level.

Picture Credit : Google 

What is the role of cultural heritage in our life?

Heritage plays a crucial role in the life of every individual. Museums and historical sites are your gateways to knowledge and prepare you for appreciating the cultural diversity of the world. How can heritage change you? Well, read on to find out!

Heritage, in simple words, is what we have inherited, what has been passed on to us over centuries. The ancient buildings, temples and the natural wealth around us tell us who we were once and how we have changed over time. Historic sites like Keezhadi and Machu Picchu teach us about our great art, culture and architecture. Old inscriptions educate us on how languages came by. Plants and animals (think Galapagos) point to our evolution. Knowing our heritage inspires us to do better. It tells us what we can achieve. When we damage or wipe out our past, we take away from future generations the right to see and experience them. Here are a few things you can do as children to explore the heritage of our land.

1. Ask questions. Connect with your heritage.

Start asking questions about old buildings in your neighbourhood. When was it built? Who lived there? How is it different from the other buildings? A sixty-year-old house in my area has a 12-foot-high ceiling, a red mud floor that feels cool underfoot and rooms built around an open courtyard. The Triplicane police station on Wallajah Road in Chennai, a heritage structure according to the Archaeological Survey of India, has a plaque that says it was opened in 1890.

Who was the Governor of Madras at that time? (Lord Connemara) Who was the Commissioner of Police? (Col T Weldon) Who designed it? (Henry Irwin, a famous architect) In what style of architecture? (Indo-Saracenic). Its history says the building was a shed for chariots before it became a police station. And why was Chennai’s Besant Nagar called Amaiyur?

2.  Visit

Wherever you are travelling, visit the local museum. You will find extra-ordinary insights about the area’s past – its people, their lives. home, food, clothing, music and dance, healthcare and traditions. For instance, the Egmore museum has a wonderful collection of Chola bronzes.

Set up in 1972, the Bastar Anthropological Museum in Jagadalpur, Chattisgarh, houses a rare collection including head-caps, shoes, jewellery, musical instruments, clothing, paintings, wood-carvings, weapons, masks, handicraft and a wide variety of objects used in daily life. It serves as a window to the living and ethnic cultures of various tribes in Bastar. Go to Kaziranga National Park, the world heritage site for the one-homed rhinoceros. If you pass through Chhatrapathi Shivaji rail terminus, find out why it is a world heritage site.

Indian Railways is the proud owner of these UNESCO World Heritage trains and routes viz the Darjeeling Himalayan Railway, Nilgiri Mountain Railway and Kalka Shimla Railway. Have you ever travelled in them? Did you know that in Europe, a path taken by pilgrims is now a World Heritage site?

3. Participate: Talk Read, write, Promote

Participate in any heritage-discovering activity. Join city/tree walks in your town. Sketch and note down in a diary what you see and hear. Watch movies that discuss your heritage. What does Ponniyin Selvan say about the Chola rule? You can spend an afternoon reading the words below the statues on Marina beach and learn a whole lot of history. Take part in art competitions that ask you to draw monuments. Organise heritage quizzes at school and family gatherings. For instance, a friend gives prizes to her kolu visitors who answer questions on her display of mythological stories. (e.g. Name the characters).

Write letters to friends/family abroad about a heritage symbol (place of worship. old building, natural wonder). Show your visiting cousins your city’s historic sights. Never miss a chance to participate in old fairs and festivals. The dragon festival is 2000 years old; the 300-year-old Raksha Bandhan festival has a wonderful story about its origin.

4. Preserve:

Worldwide, there are efforts to preserve the past. Cities were restored after World War II bombings. Fearing the Aswan High Dam in Egypt would flood the nearby valley containing the Abu Simbel temples. UNESCO got them removed and reassembled it stone by stone on higher ground.

When students of Geology. Presidency College, cleaned up the imposing statue on a landing, they discovered that it was the figure of their founder-principal, Powell, carved by John Adams-Acton in 1838 in London. The plaque below read, “erected by many Rajahs, Zamindars, former pupils and friends to mark their respect for his character and their grateful appreciation of his services in the cause of higher education for than 30 years. The students found that among the 200+ tiles around the statue, each had a different pattern! Here is an activity. On national days, after the flag-hoisting, clean up a historical statue in your town. Help clean up an old library. Paint heritage structures on the walls.

Trees are a part of heritage too! Look for old trees wherever you go. A police station in my neighbourhood is built around an ancient peepal tree. The Adyar Banyan tree (Adyar Aalamaram), located in the Theosophical society campus, Chennai, is believed to be 450 years old and is estimated to occupy 40,000 square feet. Report to the town authorities if you see trees getting cut.

5. Pledge

World Heritage Week is celebrated from November 19-25 every year to create awareness about the rich cultural heritage of the country among the general public, students and children. One activity during this time that you can indulge in is to renew the pledge: “I will not scribble on, deface or encroach upon any monument I will respect all monuments, which are a part of my country’s heritage: I will render all possible help to conserve and preserve our heritage.”

Tell people of the importance of preserving these invaluable sites by sharing news and links through social networking sites like Facebook, Instagram and Twitter. Volunteer in NGOs that organise efforts to clean up heritage areas. Listen to talks on heritage viz. Sangam Talks, Center for Indic Studies, We Care Trust, Upword, Prachyam. You could also collect donations to support UNESCO and its projects.

And above all: Would you like to study for and become a heritage conservationist? Well, think about it.

Bridges of the world

Bridges are timeless wonders that reflect the culture of a land. We introduce some of the unique bridges in the world.

Rialto Bridge-Venice, Italy

In the heart of Venice is the centuries-old Rialto Bridge. An engineering marvel designed and built in the 16th century, it is the oldest bridge surviving across the Grand Canal in the city. A peaked Venetian architecture has been given which allows ships to pass beneath the bridge.

Khaju Bridge-Isfahan, Iran

 Built in 1650 during the Safavid dynasty, the Khaju Bridge in Iran is noted for its architecture. The bridge sports 23 arches and also encompasses a dam with locks that regulate water flow.

Golden Gate Bridge San Francisco, California

All cloaked in an orange vermilion colour, the Golden Gate Bridge is one of the iconic structures in the world. Spanning the Golden Gate strait, the bridge opened in 1937 was the tallest and longest suspension bridge in the world then.

Chengyang Bridge China

A bridge constructed without nails, the Chengyang Bridge is a Wind and Rain Bridge. Built in 1912 using cedar and stone, the bridge has five pavilions with covered walkways and the wood is connected by dovetailing.

Double Decker Bridge- Meghalaya, India

Deep in the forests of Meghalaya, these bridges are being made by weaving and folding together the roots of ficus trees. These are the ancient, living bridges that grow stronger with time. A creation of both man and nature, the double-decker root bridge in Nongriat village is an architectural wonder. Many such natural bridges are being made by the villagers.

Picture Credit : Google 

Twist in the skyscraper tale

China has unveiled the world’s most twisted tower. Here’s a look at what play of light and architectural detailing can do to make some skyscrapers look twisted.

The Dance of Light skyscraper in Chongqing is located in xingfu Plaza in Jiangbei district. The 180-metre tall tower has been designed by architecture firm Aedas. According to the firm, double-curved facades have been used to create an impression of a twisted building.

The design has been inspired by the northern lights that is often seen in the Arctic. However, here light plays a key role in the twisted shape of the ‘Dance of Light’.

The reflection of light on the tower gives the tower a different look from different angles. Meanwhile, the vertical lines have emphasised the minimalistic form and the reflection and refraction from the glass has created a design statement.

MORE TWISTED STOREYS

Turning Torso

The world’s first twisted tower, Turning Torso, was designed by Spanish architect Santiago Calatrava. Ofificially opened in 2005 in Malmo, Sweden, the tower’s height is 190 metres. The building is shaped like a twisted human being.

Absolute World Towers

Absolute World is a residential condominium twin tower complex in the five-tower Absolute City Centre in Mississauga, Ontario, Canada. Built by MAD Architects, the towers are 176 metres and 158 metres tall respectively. It was completed in 2012. Interestingly, the towers have been dubbed as the ‘Marilyn Monroe’ towers due to their form.

Cayan Tower

The 306-metre tall Cayan Tower in Dubai, was designed by Skidmore, Owings & Merrill and completed in 2013. In 2013, it became the world’s tallest high-rise building with a twist of 90 degrees but was later surpassed by the Shanghai Tower. The twisting design of this tower was made by rotating each floor 1.2 degrees around a cylindrical elevator and service core.

Shanghai Tower

Shanghai Tower is the tallest building in China and the world’s third-tallest building by height to the architectural top. It was designed by the American architectural firm Gensler. The tower is in the form of nine cylindrical buildings standing atop each other. It has a total of 128 floors, all enclosed by glass facade.

Picture Credit : Google 

How does howrah bridge stands without any support of pillars?

Howrah Bridge is a long and heavy bridge but it has no support in the centre. Rabindra Setu, popularly known as Howrah Bridge, links the cities of Howrah and Kolkata. It is a 705-metre long cantilever bridge. A cantilever is a structure that juts out way beyond its base. The branch of a tree is a natural cantilever, a beam of metal jutting out from a wall to support a balcony is a cantilever, the diving board of a swimming pool may be a cantilever. In all these examples, the support exists only at one end. In a cantilever bridge, the cantilever juts out over the river from a supporting structure known as a pier. A similar cantilever juts out from a supporting structure on the opposite side of the river. The two arms meet to form the spanof the bridge. The piers at either end of the bridge support the load that a cantilever bridge has to carry so there is no need for a support in the centre.

Picture Credit : Google