Common terms and definitions for brick masonry

Common terms and definitions for brick masonry

The following words are commonly used in brick masonry and construction using cement and concrete blocks. Contractors should understand these definitions and terms in order to complete a project with high quality. Knowledge of common building terms will help contractors to communicate properly with suppliers, engineers and architects.

  • Back – The inner surface of a wall that is not exposed. The material used to create the back of the wall is called the ‘backing’.
  • Bat – The portion of brick that is cut across the width.
  • Bed – The bottom surface of bricks in each course.
  • Bevelled closer – The portion of a brick in which the whole length is beveled for maintaining half-width at one end and full-width at the other.
  • Blocking course – The top-most course of bricks immediately above the cornice to prevent the tendency of the cornice to overturn. It also adds to the aesthetics of the cornice.
  • Bond – The method of arranging bricks so that the individual units are locked together. Bonding is used to eliminate long vertical joints in the wall.
  • Closer – The portion of brick that is cut across the length.
  • Coping – The course placed upon the exposed top of an external wall to prevent the seepage of water.
  • Corbel – The extension of one or more courses of bricks from the face of a wall to serve as a support for wall plates.
  • Cornice – A projecting ornamental course near the top of a building or at the junction of a wall and ceiling.
  • Course – A horizontal layer of bricks or stones. A brick wall will have many courses.
  • Face – The exterior of a wall that is exposed. The material used to create the face of the wall is called the ‘facing’.
  • Frog – An indentation or hole on the top face of a brick, made with the purpose of forming a key for the cement. Frogs reduce the weight of bricks too.
  • Header – The brick that lies with its greatest length at right angles to the face. Any course that lays with all the bricks as headers is known as the ‘header course’.
  • Hearting – The interior portion of a wall between the facing and the backing.
  • Jambs – The vertical sides of an opening for doors and windows. These may be plain or recessed to receive the frames of doors and windows.
  • Joint – The junction between two or more bricks. If the joint is parallel to the bed of bricks in a course, it is called the ‘bed joint’. If the joint is perpendicular to the bed, it is called the ‘vertical joint’.
  • King closer – The portion of brick that is obtained by cutting off a triangular piece from the corner of the brick.
  • Lintel – A horizontal concrete, wood or iron beam that sits above a door or window opening. The lintel gives support to the bricks above a gap in a building.
  • Plinth – The horizontal course of bricks at the base of a wall, above the ground level. It is the first visible layer of a brick wall and protects the building from dampness.
  • Queen closer – The portion of brick that is obtained by cutting a brick into two portions lengthways.
  • Reveals – The exposed vertical surfaces left on the sides of an opening after a door or window frame has been installed.
  • Side – The surface forming the boundary of bricks in a transverse direction to the face and bed.
  • Sill – A horizontal member of concrete, wood or bricks that sheds water off the face of a wall, underneath a window. It also gives support to the window frame.
  • Stretcher – The brick that lies with its longest side parallel to the face of the wall. The course of bricks that is laid as stretchers is known as the ‘stretcher course’.
  • String course – A horizontal course of bricks that projects out of the face of a wall for shedding rainwater.

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LafargeHolcim is a leading building materials and solutions company that has been operating in international markets for decades. We produce cement and aggregates for construction projects, ranging from small affordable housing developments to large-scale infrastructure projects such as high-rise buildings, dams and bridges. 

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LafargeHolcim Tanzania has been supplying the country and neighbouring countries with our world-class Tembo cement brand for over 30 years. Our head office and fully-integrated plant are located in Mbeya, Southwest Tanzania.

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At LafargeHolcim Tanzania, we believe customers come first. We listen to your specific requirements to supply and develop the best solutions for your needs. As the new leader in building materials, you can also rely on our cutting-edge research and development capabilities that have resulted in the finest materials for your construction projects, whether large or small.

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Follow us on Facebook, Twitter, LinkedIn and Pinterest for the best tips on construction, handy projects and the latest industry news. See our Instagram channel for more insights into our products.

How to reduce the costs of formwork in construction

How to reduce the costs of formwork in construction

Construction projects can be costly processes, so contractors need to find ways to minimise these expenses without affecting the quality of their work. One simple way to minimise the expense of a building is to reduce the costs of concrete formwork. Sometimes formwork can account for up to 60% of the total budget for a building.

New materials, proper planning and prefabricated formwork components can allow contractors to reduce their building expenses without affecting the quality of their work. There are several other ways to reduce the price of formwork, such as using one system throughout the project, using standard form sizes and using the same level for all beams and joints.

Tips for minimising the costs of formwork

  • Use a single framing system for the whole project. This not only helps contractors to learn the formwork system easily, but it also helps to minimise the costs of the formwork set-up.
  • Use the same depth of formwork for all concrete beams. This will help to standardise beam size and shape, making the project quicker and easier.
  • Stick with the same formwork moulds for beams, even if the spans and loads of these beams are different. Contractors can modify the concrete ratios to compensate for various loads on beams.
  • Simplifying the formwork can also help to create uniform shapes and sizes for concrete pillars and beams. 
  • Reuse formwork as much as possible.
  • Use a constant floor-to-floor height between the different levels of a building. This will ensure standardised pillar heights and formwork moulds.
  • Orientate all framing in one direction to save money and time when pouring concrete into the formwork.
  • Consider flat plate formwork for concrete spans up to 7.5 metres as this framing system is the cheapest and fastest to construct.
  • Determine a standard time for the stripping of formwork from poured concrete. This will allow a project to run smoothly and on schedule.

These tips are based on a few general principles. Standardisation and time-management are two of the biggest factors that can reduce the costs of formwork. Contractors need to use standard formwork frames and create concrete beams and pillars of uniforms sizes. This helps to speed up the construction process and in this industry, time is money.

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LafargeHolcim is a leading building materials and solutions company that has been operating in international markets for decades. We produce cement and aggregates for construction projects, ranging from small affordable housing developments to large-scale infrastructure projects such as high-rise buildings, dams and bridges. 

___

LafargeHolcim Tanzania has been supplying the country and neighbouring countries with our world-class Tembo cement brand for over 30 years. Our head office and fully-integrated plant are located in Mbeya, Southwest Tanzania.

___

At LafargeHolcim Tanzania, we believe customers come first. We listen to your specific requirements to supply and develop the best solutions for your needs. As the new leader in building materials, you can also rely on our cutting-edge research and development capabilities that have resulted in the finest materials for your construction projects, whether large or small.

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Follow us on Facebook, Twitter, LinkedIn and Pinterest for the best tips on construction, handy projects and the latest industry news. See our Instagram channel for more insights into our products.

Why brick and cement are sustainable building options

Why brick and cement are sustainable building options

Brick and cement are some of the most common building materials used in the construction industry. They are both sustainable materials that are made from natural elements. Cement is largely made up of limestone and other minerals, while bricks are made from clay and soil. LafargeHolcim Tanzania manufactures Tembo cement at its facility in Mbeya. Many of the bricks in Tanzania are made at small-scale plants.

Clay is an abundant natural element, but some bricks can be made with shale, soil (for soil-stabilised concrete blocks) or recycled brick dust. Similarly, post-industrial waste products, such as fly ash, silica fume and slag, can be used to make cement. Brick and cement can be manufactured from a variety of materials but their long-term strength and durability make them sustainable construction materials.

Brick manufacturing process

Brick-making facilities are usually set up close to the source of the raw materials. The process of making bricks is quite simple and it produces very little waste materials. Wet clay is packed into brick moulds and compressed. The wet bricks are removed from the mould and placed in a large oven which bakes the clay into the hard brick. 

Unfired clay is easily recycled into new bricks by simply wetting it and mixing it in with the raw materials. Fired bricks that are cracked or damaged can be crushed and recycled back into the production process, or used as a landscaping and rubble material. The brick ovens are normally fuelled by natural gas, although coal and wood are sometimes used in small-scale operations.

Bricks can be manufactured anywhere in the world, so they are usually sold to local markets within the same region as where they are manufactured. This means that less fuel is needed for transport and fewer carbon emissions are released into the air. The recyclability and durability of bricks make them sustainable building materials.

Brick and cement construction is eco-friendly

Once the bricks are sold to contractors, there is only a small amount of waste that is generated by brick construction. Only partial bricks, cracked bricks and unused cement mortar are the waste products from brick construction – all of which can be recycled into rubble for other building projects.

Brick masonry is a good insulator, which means that cool air can be kept inside on hot days and warm air can be kept inside on cold nights. The insulating properties of clay bricks and cement help to reduce the need for air conditioning or heating units, which use electricity and can be a source of air pollutants.

When a building has reached the end of its useful life, the bricks can be carefully deconstructed and reused in other building projects. Damaged bricks and mortar can be used for rubble or landscaping purposes. Brick masonry requires very little maintenance and the buildings can last for centuries. This makes brick and cement construction a sustainable building option for contractors.

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LafargeHolcim is a leading building materials and solutions company that has been operating in international markets for decades. We produce cement and aggregates for construction projects, ranging from small affordable housing developments to large-scale infrastructure projects such as high-rise buildings, dams and bridges. 

___

LafargeHolcim Tanzania has been supplying the country and neighbouring countries with our world-class Tembo cement brand for over 30 years. Our head office and fully-integrated plant are located in Mbeya, Southwest Tanzania.

___

At LafargeHolcim Tanzania, we believe customers come first. We listen to your specific requirements to supply and develop the best solutions for your needs. As the new leader in building materials, you can also rely on our cutting-edge research and development capabilities that have resulted in the finest materials for your construction projects, whether large or small.

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Follow us on Facebook, Twitter, LinkedIn and Pinterest for the best tips on construction, handy projects and the latest industry news. See our Instagram channel for more insights into our products.

New energy-saving technologies for buildings

New energy-saving technologies for buildings

Sustainability is becoming a more popular way of doing things. Reducing waste, conserving electricity and having a lower impact on the environment are necessary changes that people are starting to make. The construction industry is no exception. Sustainability has driven the advancement of new energy-saving technologies in buildings.

Some of these technologies include LED lighting, modern insulation, reflective roofing materials, heating and cooling systems, as well as waste-to-energy generation. These are new ways of building homes and office spaces that reduce the building’s impact on the environment. Here are some of the new energy-saving technologies being used by contractors currently:

Connected and Smart Buildings

Some homes and office spaces have an integrated wireless system that automatically controls various aspects of the building. Sensors can detect and make a change to air conditioning and heating systems, the lighting circuits, geysers and a variety of other elements that require energy. These automated systems can reduce the energy consumption of a building by switching units off when they are not needed.

Advancements in window technology

When one thinks of technology, they probably do not think about glass windows. New adhesive coatings can be applied to windows that change colour in bright sunlight – like glasses that dim themselves when the wearer steps into the sun. This technology is being used on modern high-rise buildings already.

These coatings reduce glare inside the building, cut down external light and heat reflections from the windows and lower the internal temperature of the building. This helps to save energy on cooling systems during the day. At night, the colour coating returns to its transparent state, allowing the maximum amount of light into the building. 

Energy-saving lighting circuits

Most modern buildings are being fitted with energy-efficient LED lights, as opposed to fluorescent tubes or traditional light bulbs. LED lights use just 10% of the energy needed to power an incandescent bulb. This means that buildings with LED lighting circuits are 90% more efficient – and homeowners can change their bulbs themselves.

Another lighting system currently being used requires no energy during the day. Light pipe systems use a light collector to ‘pipe’ the light falling on the roof to the interior spaces of the building. The sunlight travels through these reflective pipes and is dispersed inside the building, similar to how a skylight works. These systems use zero electricity during the day, but conventional lighting will be needed at night.

Eco-friendly insulation

A new type of foam insulation is being installed on modern buildings. This insulation is made from environmentally-friendly materials and advanced composites. The insulation helps to regulate the internal temperature of a building. It keeps the building cool on hot days and traps the heat inside on cold days. Insulation is a vital part of building in colder climates, but Tanzanian contractors also use it to keep homes cool in our hot climate.

Electricity and heat generation

New technologies have been developed that enable the cogeneration of electricity and heat from the same unit. The electricity powers all the lights and wall sockets while the heat from the generator is captured and used to heat geysers and wall-mounted heating systems. This cogeneration minimises energy wastage.

Another electricity generation technique currently being used in Africa is waste-to-energy. This is a system whereby household and organic waste is burned in a furnace. The heat is then used to power an electricity generator, effectively turning waste into power. These systems are being installed at shopping malls, hotels and office spaces where there is enough waste produced to run the system.

Reflective roofing materials

Like the window coatings that help to regulate internal temperatures of buildings, new reflective paint is being used on the roofs of high-rise buildings. Contractors spray this coating on the roof to reflect the sun’s light and heat. This lowers the heat absorption of the roof and cools down the interior of the building.

These technologies are just a few of the modern advancements being used in construction today. They are making our cities and suburbs more efficient, saving money for owners and lowering the environmental impact of human activity. Sustainable technologies such as these are the future.

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LafargeHolcim is a leading building materials and solutions company that has been operating in international markets for decades. We produce cement and aggregates for construction projects, ranging from small affordable housing developments to large-scale infrastructure projects such as high-rise buildings, dams and bridges. 

___

LafargeHolcim Tanzania has been supplying the country and neighbouring countries with our world-class Tembo cement brand for over 30 years. Our head office and fully-integrated plant are located in Mbeya, Southwest Tanzania.

___

At LafargeHolcim Tanzania, we believe customers come first. We listen to your specific requirements to supply and develop the best solutions for your needs. As the new leader in building materials, you can also rely on our cutting-edge research and development capabilities that have resulted in the finest materials for your construction projects, whether large or small.

___

Follow us on Facebook, Twitter, LinkedIn and Pinterest for the best tips on construction, handy projects and the latest industry news. See our Instagram channel for more insights into our products.

How to set out a building plan on the ground

Architects building plan

Before contractors can begin a construction project, they first need to lay the building plans on the ground. This is the process of making the outline of the structure, to the exact dimensions, on the location of where it will be built. The building plan will show contractors where to dig and lay the foundations for the building.

The building plan is often marked by pegs and string, but some contractors like to use white paint on the ground. Pegs are hammered into the ground and attached by a string along the centreline of walls. Contractors need to make sure that the pegs and string follow the architect’s drawings perfectly. 

Steps to laying a building plan on the ground

  1. Clear any long grass and rocks from the construction site where the building will stand. Remove any debris and skim off the topsoil. This will make the marking process easier and clearer.
  2. From the architect’s drawing, start by hammering a peg into the ground at one of the corners of the building (call it point A). Measure the distance of the wall, using the architectural plan as a reference, and place another peg in the ground where the next corner of the wall will be (point B). 
  3. Place a peg two metres away from point A and point B and connect these two pegs with the string. These pegs (call them A1 and B1) will help contractors excavate the foundations later without having to move the string or corner pegs.
  4. Repeat this process of placing pegs at all the corners of the walls (points C and D) and placing additional pegs two metres away. Attach all the outer pegs with string. Each corner point should have two pegs (corner A will have peg A1 joining B1 and A2 joining D2). Where the strings cross will mark the exact corner of the walls.
  5. To make sure that the corners are 90°, the centre points of the rooms needs to be calculated. Measure the distance between opposite corners (point A and point C) on the architect’s drawings. Make sure that the real distance between the pegs at point A and point C match the distance on the drawing. You may have to move the pegs a bit to make these diagonal measurements are exact.
  6. Where the diagonal strings cross is the centre point of the room. The opposing walls (AB and CD or AD and BC) should be the same distance from this centre point.
  7. Once all the strings are laid, the contractors can start excavating the foundations. The extra two metres of string at each corner will allow the contractors to dig the foundations without having to excavate any corner pegs. The strings will be used as a guide for the centreline of the walls.
  8. Some contractors like to spray white spray paint on the ground or use lime to demarcate the path of the wall underneath the strings. This just helps to dig the foundation more accurately.

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LafargeHolcim is a leading building materials and solutions company that has been operating in international markets for decades. We produce cement and aggregates for construction projects, ranging from small affordable housing developments to large-scale infrastructure projects such as high-rise buildings, dams and bridges. 

___

LafargeHolcim Tanzania has been supplying the country and neighbouring countries with our world-class Tembo cement brand for over 30 years. Our head office and fully-integrated plant are located in Mbeya, Southwest Tanzania.

___

At LafargeHolcim Tanzania, we believe customers come first. We listen to your specific requirements to supply and develop the best solutions for your needs. As the new leader in building materials, you can also rely on our cutting-edge research and development capabilities that have resulted in the finest materials for your construction projects, whether large or small.

___

Follow us on Facebook, Twitter, LinkedIn and Pinterest for the best tips on construction, handy projects and the latest industry news. See our Instagram channel for more insights into our products.

Why concrete strength tests are performed after 28 days

Concrete cylinders for strength tests

Contractors often rely on the strength test result of concrete conducted at the age of 28 days. The strength results at 28 days are considered standard and contractors rely on these to determine the integrity of the resultant structure.

Concrete gains strength over time. It can take anywhere from a few weeks to a few years for different concrete mixes to reach almost 100% strength. Contractors generally perform strength tests four weeks after pouring – or 28 days. During this time, all concrete batches will have cured and strengthened rapidly. After 28 days, the rate of strengthening slows down.

How concrete gains strength over time

Standard grades of concrete will generally gain 16% of its strength after the first day, 40% after three days, 65% after seven days, 90% after 14 days and almost 100% after 28 days. This is why compressive strength tests are performed after 28 days. The concrete will be near-optimal strength and is unlikely to change much more after four weeks of curing.

The figures above clearly show how rapidly concrete sets and cures during the first four weeks. After this time, the rate of strengthening slows down considerably, gaining just one more percent of strength in a number of months after being poured. After the first two weeks, concrete only gains nine percent strength in the next two weeks, so the slowing of the rate begins after 14 days.

Concrete takes about 12 months to reach almost 100% strength

Most concrete will reach 100% strength about a year after pouring. Contractors only need to wait for 28 days before performing strength tests as it is close enough to maximum strength to form reliable results. The basis for evaluation is so close to perfect after four weeks that there is no point waiting for another 11 months to do the strength tests.

Although all concrete mixes are different in terms of how rapidly they cure, 28 days has become the standardised length of time to wait. Some rapid-setting concrete mixes may cure within half the time, contractors should still wait for four weeks to perform tests on the structure unless time is extremely limited and deadlines are threatening the project.

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LafargeHolcim is a leading building materials and solutions company that has been operating in international markets for decades. We produce cement and aggregates for construction projects, ranging from small affordable housing developments to large-scale infrastructure projects such as high-rise buildings, dams and bridges. 

___

LafargeHolcim Tanzania has been supplying the country and neighbouring countries with our world-class Tembo cement brand for over 30 years. Our head office and fully-integrated plant are located in Mbeya, Southwest Tanzania.

___

At LafargeHolcim Tanzania, we believe customers come first. We listen to your specific requirements to supply and develop the best solutions for your needs. As the new leader in building materials, you can also rely on our cutting-edge research and development capabilities that have resulted in the finest materials for your construction projects, whether large or small.

___

Follow us on Facebook, Twitter, LinkedIn and Pinterest for the best tips on construction, handy projects and the latest industry news. See our Instagram channel for more insights into our products.

Types of inspection for concrete structures

Inspection of concrete bridge

Inspecting concrete is a necessary step in the proper maintenance of buildings and  structures. It allows contractors to find any faults, such as cracks and salt damage, before they become bigger problems. Inspections will provide assurance that the concrete is structurally safe at any given period, so they need to be performed once every couple of months at least.

During inspections, any defects or problems need to be recorded. This allows contractors to keep an accurate record of when issues occur and how they are resolved. This information can also help engineers and architects to plan the repair work and strengthen the concrete structure.

Types of concrete inspection

There are three main types of inspection that need to be performed on concrete structures. These are; routine, detailed and special inspections.

  1. Routine inspection – This is the examination of concrete structures at regular intervals. Routine inspections are usually quick and they only look at the general condition of the structure. Each examination is recorded in a book. The inspector will make a visual assessment and use simple tools to determine the condition of the concrete. The purpose of routine inspections is to find cracks, chips, delamination, spalling, salt build-up, rust streaks and deformation in the concrete.
  2. Detailed inspection – This is a thorough examination of a concrete structure that takes longer than a routine inspection. A detailed inspection requires the assessor to closely examine the concrete and use specialised tools to accurately determine the state of the structure. These inspections need to be carried out by trained engineers who can plan comprehensive repairs.
  3. Special inspection – These examinations are done in special circumstances or after unusual events. They are usually performed when a building is being extended vertically, when reinforced concrete pillars show signs of stress, when a foundation starts to collapse, after earthquakes or ground tremors, after a fire, after a flood and after accidents. Any of these circumstances or events will require an engineer to perform a special inspection, which looks at very specific aspects of a structure’s integrity.

These three inspections ensure that buildings and other load-bearing concrete structures remain in perfect condition. Routine inspections must be carried out regularly, white detailed and special inspections are more needs-based – they are carried out as and when necessary. All concrete inspections must be recorded and performed by trained engineers and contractors.

___

LafargeHolcim is a leading building materials and solutions company that has been operating in international markets for decades. We produce cement and aggregates for construction projects, ranging from small affordable housing developments to large-scale infrastructure projects such as high-rise buildings, dams and bridges. 

___

LafargeHolcim Tanzania has been supplying the country and neighbouring countries with our world-class Tembo cement brand for over 30 years. Our head office and fully-integrated plant are located in Mbeya, Southwest Tanzania.

___

At LafargeHolcim Tanzania, we believe customers come first. We listen to your specific requirements to supply and develop the best solutions for your needs. As the new leader in building materials, you can also rely on our cutting-edge research and development capabilities that have resulted in the finest materials for your construction projects, whether large or small.

___

Follow us on Facebook, Twitter, LinkedIn and Pinterest for the best tips on construction, handy projects and the latest industry news. See our Instagram channel for more insights into our products.

How to expose aggregate on concrete floors

How to expose aggregate on concrete floors

Some concrete projects call for smooth gravel stones to be exposed for textural and decorative purposes. There are several ways of exposing aggregate on concrete floors. It all depends on the desired appearance and size of the project. Only the top of the stone is revealed, while the rest remains permanently embedded in the concrete. Usually, surface mortar is removed to a depth of no more than one-third of the diameter of the aggregate particle.

1. Brushing and washing

This method doesn’t require special tools or chemical retarders and is the oldest and simplest way of exposing aggregate on concrete surfaces. The thin layer of surface mortar covering the aggregate is simply washed away by spraying with water and scrubbing with a broom until the aggregate is exposed to the desired depth. 

The timing of doing this is very important. Begin as soon as the surface mortar can be removed without overexposing or dislodging the aggregate – the concrete will need to have started setting already, so wait an hour or so after pouring. You can do a test by lightly brushing the surface mortar away in a small area with a stiff-bristled broom.

2. Using a surface retarder

Most contractors use a chemical surface retarder to expose the aggregate. They do this by spraying the retarder onto the slab surface immediately after placing and finishing the concrete. Doing this delays the setting of the concrete and allows them to remove the cement paste a day or so later. This can be done by either pressure washing or scrubbing the concrete surface. Exposing the stones this way can be very useful when working in hot weather or working on large jobs such as pavements and long pathways.

3. Abrasive blasting

Abrasive blasting allows the aggregate to be exposed after the concrete has set and hardened. Either shot blasting or sandblasting can be used. A disadvantage of this method is that it can dull the aggregate’s appearance due to fracturing the surface of the smooth stones. If you want to preserve the shape and full color intensity of the aggregate, this is not the best method to use. 

These three methods of exposing aggregate on a concrete surface allow contractors to create textured and decorative structures. The most common application of this building method is on concrete pathways, parking lots and pavements where the stones give added grip and a pleasing look to the grey concrete.

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LafargeHolcim is a leading building materials and solutions company that has been operating in international markets for decades. We produce cement and aggregates for construction projects, ranging from small affordable housing developments to large-scale infrastructure projects such as high-rise buildings, dams and bridges. 

___

LafargeHolcim Tanzania has been supplying the country and neighbouring countries with our world-class Tembo cement brand for over 30 years. Our head office and fully-integrated plant are located in Mbeya, Southwest Tanzania.

___

At LafargeHolcim Tanzania, we believe customers come first. We listen to your specific requirements to supply and develop the best solutions for your needs. As the new leader in building materials, you can also rely on our cutting-edge research and development capabilities that have resulted in the finest materials for your construction projects, whether large or small.

___

Follow us on Facebook, Twitter, LinkedIn and Pinterest for the best tips on construction, handy projects and the latest industry news. See our Instagram channel for more insights into our products.

Guidelines for fire protection of high-rise buildings

High-rise building on fire

Fire safety is an important factor for any building’s design and construction. The architect and engineers need to work together to ensure that buildings comply with safety standards and meet the necessary fire protection regulations. High-rise buildings present a particular challenge when it comes to fire protection and safety.

Tall residential buildings and office blocks have longer evacuation times, more restricted firefighter accessibility, greater smoke containment and more difficult fire control. In many high-rise buildings, the only fire escapes are staircases – occupants cannot use the windows to escape the flames and smoke. 

Making high-rise buildings safe from fire

Here are some guidelines for constructing high-rise buildings with good fire protection mechanisms:

  • The national building code should be followed when designing and constructing tall buildings. This document will outline all the procedures and regulations that need to be followed, including fire escape guidelines and emergency evacuation procedures.
  • Any high-rise structure should have at least one staircase that is designated as a fire escape. The doors should be linked to a fire alarm and kept closed (but not locked) to prevent people from triggering the alarm unnecessarily. The closed doors will also isolate the stairwell from the smoke and external open air space, which could speed up the spread of the fire.
  • The high-rise building should have access to its own water supply in the case of a fire. If no municipal fire hydrants exist nearby, the building should have its own borehole or underground water tank to supply water for firefighters. This water supply needs to be connected to accessible fire hoses on every corridor of every floor.
  • Smaller, dry-powder fire extinguishers should be located in convenient and accessible places throughout the building. Security personnel should also be given access to fire extinguishers and they must be trained in firefighting techniques.
  • A detailed plan of the building should be accessible to all occupants. This plan will highlight fire escape routes, as well as the locations of fire hoses and extinguishers.
  • Another building plan should also be made available to local firefighters that describes where external fire hydrants and water pipelines are located. They can use this plan to see the cross-sectional layout of the building and plan their firefighting strategy accordingly.
  • The electric circuits in a high-rise building should be separated from one another. Two lighting circuits should be installed – one for regular use and one at floor level in case of smoke and flames. The elevators should run on a separate circuit that can be disabled if a fire breaks out. 
  • All tall buildings over the height of 25 metres should have backup generators that can switch on in the case of a power failure due to fire. Lighting is essential in an emergency evacuation event.
  • All the requirements outlined in the building code should be signed off by the building owner, the architect, contractors and local council. The government can request further building plans and drawings as they see fit.

These guidelines will help to make high-rise buildings safer in the event of a fire. In any apartment block or office space with hundreds of occupants, the risk of fire is increased – especially in high-rise buildings with multiple homes and kitchens. All architects and contractors must be familiar with their national building code and ensure that structures are built in-line with these regulations.

___

LafargeHolcim is a leading building materials and solutions company that has been operating in international markets for decades. We produce cement and aggregates for construction projects, ranging from small affordable housing developments to large-scale infrastructure projects such as high-rise buildings, dams and bridges. 

___

LafargeHolcim Tanzania has been supplying the country and neighbouring countries with our world-class Tembo cement brand for over 30 years. Our head office and fully-integrated plant are located in Mbeya, Southwest Tanzania.

___

At LafargeHolcim Tanzania, we believe customers come first. We listen to your specific requirements to supply and develop the best solutions for your needs. As the new leader in building materials, you can also rely on our cutting-edge research and development capabilities that have resulted in the finest materials for your construction projects, whether large or small.

___

Follow us on Facebook, Twitter, LinkedIn and Pinterest for the best tips on construction, handy projects and the latest industry news. See our Instagram channel for more insights into our products.

The role of calcium chloride in concrete

The role of calcium chloride in concrete

Admixtures are chemicals that are mixed in with the cement, aggregate and water in a concrete batch. These chemicals have various effects on concrete; some make it waterproof, others make it more workable. Calcium chloride is an admixture that speeds up the hydration process and makes the concrete set quicker with high initial strength.

This can have various benefits. By speeding up the initial setting time, building projects can progress at a more rapid pace. It also allows contractors to build on top of new concrete within a number of days. This is ideal for load-bearing structures, such as columns and beams.

How to add calcium chloride to concrete

Calcium chloride can be purchased as flakes, pellets, granules or as a liquid. All forms of this chemical are soluble; they can dissolve in water, so it is recommended to use the liquid form. No more than two percent of a concrete batch should be calcium chloride. 

The chemical reacts directly with cement, not the other ingredients in a concrete batch, so it cannot come into direct contact with cement until a concrete batch is being mixed. Contractors should dilute the calcium chloride in the water for the concrete batch and then mix it with the sand and crushed stone. The cement can then be added to the mix.

Effects of calcium chloride on concrete

As mentioned before, calcium chloride speeds up the setting time of concrete and allows it to develop high initial strength. This admixture can be used in low-temperature conditions where concrete would normally take a few days to set. When using calcium chloride, contractors need to make sure that the concrete does not set before they have finished working with it.

Calcium chloride does not affect the water ratio required for a concrete batch. However, it can cause the mix to become stiff, so contractors may need to add a bit more water to keep the mix workable. This admixture also reduces bleeding in concrete once it has been poured, which can sometimes increase drying shrinkage. Contractors need to keep the surface of the concrete damp to prevent it from cracking.

In some cases, calcium chloride can cause a white deposit to form on the surface of the cured concrete. This efflorescence does not happen in every case, but it is not the same as salt damage – contractors do not need to be concerned. These white deposits cannot be washed away with water, so contractors must dilute hydrochloric acid with water and pour it over the surface of the concrete. Brush the diluted acid away with a broom and always wear rubber gloves.

Advantages of using calcium chloride in concrete

  • Development of high initial strength.
  • Reduced initial and final setting time.
  • Reduced bleeding.
  • Improved workability in cold conditions.
  • Fast work turnaround.
  • Cost-effective

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LafargeHolcim is a leading building materials and solutions company that has been operating in international markets for decades. We produce cement and aggregates for construction projects, ranging from small affordable housing developments to large-scale infrastructure projects such as high-rise buildings, dams and bridges. 

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LafargeHolcim Tanzania has been supplying the country and neighbouring countries with our world-class Tembo cement brand for over 30 years. Our head office and fully-integrated plant are located in Mbeya, Southwest Tanzania.

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At LafargeHolcim Tanzania, we believe customers come first. We listen to your specific requirements to supply and develop the best solutions for your needs. As the new leader in building materials, you can also rely on our cutting-edge research and development capabilities that have resulted in the finest materials for your construction projects, whether large or small.

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