Author: Dhrubajyoti Roy

A concrete block is a building material that is used to build walls. It is a pre-cast concrete product that is used in the construction industry. Pre-cast means that the blocks are made and hardened before they are brought to the construction site. Concrete blocks are standard-sized regular blocks that are used to make walls. They are also known as “Concrete Masonry Units (CMU).” These blocks usually have one or more cavities and their sides may be smooth or may have a certain design. There are different types of concrete blocks available in the market.

Concrete blocks are made in plants that specialize in the manufacture of such blocks. Some of these plants are automatic while others are manual. Manually operated concrete block-making machines can be installed at the project site itself. With manual machines at the site, the transportation charges for the concrete blocks are. Concrete blocks are manufactured in four steps:

Selection and Proportion

Concrete blocks are made up of fine and coarse aggregates, cement, and water. The ingredients are firstly selected according to the requirement which will give the desired strength to the concrete blocks. The careful grading of aggregates will depend upon the strength, texture, and economy of concrete blocks. Aggregates used in the making of concrete blocks include crushed stones, gravel, furnace clinker, etc. which are selected depending on the weight, texture, and composition of the unit desired. The cement that is used for making such blocks is ordinary Portland cement and the water Is normal potable water.

Mixing

Once the selection and carefully matched proportion of the material is done, the second step is to mix all these materials together. The mixture of water, cement, and aggregates should be done in a proper way and it is better to mix these ingredients in a mechanical mixer. If mixed using a hand, one should be extremely careful while doing so.

Molding

After the mixture is made properly, the concrete mix is poured into the mold box up to the top level. Filling the box up to the top level is compulsory. The vibration of concrete is done inside the mold box until the concrete has finally settled in the box uniformly. The excess concrete is removed from the face of the mold box and leveled by using plywood. For general construction purposes, the concrete mixture for concrete blocks contains a higher percentage of sand and a lower percentage of gravel and water. This produces a very dry, hard, and stiff mixture that has no problem holding its shape when it is removed from the mold block.

Curing

After the block is cast, it is watered for about one day. The curing process is done for a minimum of seven days and a maximum of twenty-eight days. The longer the concrete blocks are cured, the better will be the quality of the block.

Different types of concrete blocks

There are different types of concrete blocks available in the market today. Concrete blocks are generally divided into seven categories which are as follows-

Solid Concrete Blocks

These concrete blocks are heavy in weight and have a solid appearance. These blocks are made using dense aggregates, are very strong, and help make the structure very stable. Hence they are preferably used in load-bearing walls. The sizes of these blocks are also much larger than the sizes of bricks and hence construction using such blocks takes very little time. Solid concrete blocks are very similar to concrete bricks but are costlier and heavier in comparison to bricks. That is why they can withstand more forces than bricks.

Hollow Concrete Blocks

These concrete blocks contain voids that are greater than 25% of their entire area. The solid area of the brick should be more than 50. They are made using lightweight aggregates and hence are very lightweight. They are also very easy to install and the voids are filled with lightweight mortar as well while making a structure.

There are a total of eight types of hollow concrete blocks which are:

Stretcher Block

Corner Block

Pillar Block

Jamb Block

Partition Block

Lintel Block

Frogged Brick Block

Bull Nose Block

Aerated Autoclaved Concrete Block (AAC)

These types of concrete blocks are usually compared with bricks and are very different in a lot of ways. These concrete blocks are larger and lighter versions of bricks. They are usually made using the same ingredients as bricks but with a different composition. Due to this, these blocks are way cheaper than bricks. According to recent studies, these blocks have helped reduce the overall steel and concrete consumption by 15% and 10%. These blocks also, take less construction time in comparison to bricks, are fire resistant, and can adapt to various surfaces well.

Concrete Bricks

Concrete bricks are mainly small blocks that are rectangular in shape and arranged together to create a rigid wall. These bricks are usually made of cooked clay or concrete. Some use only concrete to manufacture such bricks while others play with the cement and aggregate ratio for cost-cutting purposes. These bricks are usually used in facades, and fencing as they are lightweight and give a very slick look.

Paving Blocks

These blocks are just rectangular or square blocks that are manufactured using reinforced concrete. They are mostly used for paving purposes and must be painted with high-visibility concrete paints so that people using vehicles can easily notice the blocks. Also, these blocks must be strong and rigid enough as they must be able to withstand vehicular and passenger weight.

These were the different types of concrete blocks that are usually used today.

Advantages and disadvantages of concrete blocks

Advantages

• Concrete blocks are more fire resistant and provide better thermal insulation and sound absorption in comparison to bricks.
• Concrete blocks save the land of farmers and are usually used for brick manufacturing plants.
• The making of concrete blocks takes less time, is easier, faster, and is stronger in comparison to bricks.
• The perfect shape of the concrete blocks makes the masonry work very simple.
• Plastering is not needed really in concrete blocks.
• Concrete blocks are very environmentally friendly in comparison to bricks.

Disadvantages

• Wider and larger cracks occur in structures made using concrete blocks in comparison to bricks.
• Sometimes shrinkage occurs due to the movement of moisture in concrete blocks.
• Plumbing issues arise in concrete blocks in comparison to bricks.

Conclusion

Concrete blocks are slowly being used heavily and they are in fact replacing bricks and steel structures. Once we can overcome the disadvantages, it is not very far that concrete bricks will be used everywhere as they are a cheaper and more environmentally friendly option.

The International Commerce Centre or the ICC is a mixed-used skyscraper located in West Kowloon, Hong Kong. It was completed in the year 2010 and is a part of the Union Square project on the top of Kowloon station which is a transportation hub that feeds a network that ferries over 11 million passenger journeys per day. It is a very important tower for China as it invites a huge portion of tourists to visit Hong Kong since it has the highest observatory, amazing malls, and great subway transportation. The tower is part of the second financial district of Hong Kong which is a hotspot for tourists as well as people coming to China for business purposes. It has residential, commercial, and business facilities which make the building one of the busiest structures in China.

International Commerce Centre Floors

The ICC is the tallest building in Hong Kong and the 10^th tallest building in the world as of 2016. The height of the building is 484 meters which is about 1588 feet. The structure is said to consist of the world’s second-highest hotel and the world’s highest swimming pool. Hong Kong city’s highest observation deck is located here.  The International Commerce Centre floors are a total of 112, out of which 108 are located above the ground and 4 are located below the ground. The building has a total of 83 elevators and 312 hotel rooms. It has a total number of 1700 parking spaces.

The International Commerce Centre Floors were divided by the different usage of the space. In the basement of the building, lies the Elements Shopping Mall that opened in October 2007. It offers one of the most luxurious shopping experiences in the world. Floors 102 to 118 are occupied by The Ritz-Carlton Hotel, which is a five-star hotel. The world’s highest swimming pool and bar (named Ozone) can be found on the 118^th floor as well.  The observation deck which is a key feature of the tower is located on the 100^th floor and is called Sky100. The deck was made open to the public in April 2011. Various five-star restaurants can be found on the 101^st floor and the rest of the building contains class-A office spaces.

Development

The developer of the building is Sun Hung Kai Properties and MTR Corporation Limited which is Hong Kong’s largest property developer and metro operator respectively. The skyscraper was designed by an American Architecture firm called Kohn Pedersen Fox Associates (KPF) in association with Wong & Ouyang. The ICC was not completed in a single go; rather it was built in phases from 2007 to 2010. The original plan for the building was for it to be 574 meters tall which is about 1883 feet with 102 floors. It was supposed to be named Kowloon Station Phase 7. However, the height has to be scaled back as regulations of the city did not permit buildings to be taller than the surrounding mountains. The construction of the structure was halted for a bit in September 2009 as there was an accident involving a lift shaft that resulted in the death of six workers.

The design of the building was selected through an invited competition that happened in 2000 and the winner was KPF. At first, after taking every aspect of planning into consideration including wind speed, the firm came up with a circular plan for the tower. However as future financial tenants favored square floor plates, KPF had to modify its circular design. However, it was found that wind loading on rigid shapes performs poorly and requires more materials which results in a higher cost of construction. Hence, the rigid square plan was modified by the firm by introducing notched corners which made it possible to act like the previous circular plan. The curtain wall of the tower is sculpted into a series of overlapping panels that were inspired by the scales of a dragon giving the tower an aesthetically pleasing look. The ICC is not only known for its grand height but also for its unique design elements.

The tower contains a lot of innovative design techniques which were very new during that time in Hong Kong. It has double-deck elevators which helped save space and made traveling quicker. They were the first such elevators in Hong Kong. The building also used high-strength concrete that was pumped up to the top of the structure using a new pump that conveyed concrete 1000 feet higher than normal pumps. This helped in saving a lot of money.

Why is it so popular among the tourists?

With tourists flocking around from all over the world, the ICC is one of the busiest buildings in Hong Kong. The amazing views from the tower, the luxury shopping experience, staying at the Ritz Carlton Hotel, the light display, and dining at all the fancy restaurants; all these elements in the building make it an unavoidable spot for tourists coming to the city.

The World Tower Mumbai is a bunch of three supertall skyscrapers in the skyline of central Mumbai by the Lodha Group. It is a residential development located in Lower Parel, South Mumbai, India. It is a mixed-use development situated on a 17.5-acre site of the defunct Shrinivas Mill. The project consisted of three sky-high towers namely, World One, World View, and World Crest. For making the three towers, there were two civil contractors that were involved, namely, Arabian Construction Co. and Simplex for the World One tower and Muscovite Group for the World Crest and World View towers.

Out of all the three towers World One stands at a height of about 280.2 meters which is around 919 feet. It was designed by the architecture firm Pei Cobb Freed & Partners, along with the civil engineering firm Leslie E. Robertson Associates. The World View Tower is around 285 meters and the World Crest is around 223 meters.

The real estate giant Lodha Group wanted to bring the citizens of India one of the finest living experiences in the form of the World Towers Mumbai. They wanted the tower to resonate with aristocracy and luxury living. Every nook and corner of the tower is filled with spectacular opulence with the most exquisite apartments. The towers are adorned with beautiful courtyards, pools, and gardens. It also consists of a 5-level clubhouse, a spa and fitness center, an open-air sports arena, and decks that provide the most amazing views of Mumbai.

The main idea behind the creation of the World Tower Mumbai was to create a space that resonates with the vibe of South Mumbai. The towers have a unique curvilinear shape and are made with a combination of glass and steel. The structure is a modern design with functionality being the driving force while creating the design. The apartments inside the towers are beautifully designed with balconies that offer the best views of the city. 

Because of its amazing location, the World Tower Mumbai provides easy access to the best amenities one can possibly find in India such as a 2-acre sports arena, art lounges, and a library. The Lodha Place Park which is a public park is located to the left of the tower, while the finest restaurants of Mumbai are located on its right. The towers offer a lifestyle that not many people can afford and are built to resonate with the crowd of people who can afford such luxurious living.