What is exposed aggregate concrete

What is exposed aggregate concrete

Exposed aggregate concrete serves two purposes; it is both decorative and functional. It is a term used to describe a concrete surface, such as a floor, path, pavement or parking lot, that has exposed gravel. This method is used to create flat surfaces that not only look good, but they also provide extra grip in wet conditions.

Exposed aggregate concrete is made by removing the top layer of cement and fine aggregate from freshly-poured concrete. This leaves the large aggregate particles (crushed stone or gravel) exposed and sticking out the top of the surface slightly. It is a durable and skid-resistant surface that is often used to make driveways, paths, pool decks and floors safer.

Methods for creating exposed aggregate surfaces

There are many ways to create these types of surfaces, but contractors generally use four methods.

  1. Standard – The standard way to create exposed aggregate surfaces is by mixing a normal batch of concrete; cement, sand, water and crushed stone. The concrete is then poured and left for an hour or so to harden slightly. A broom is then used to vigorously sweep the surface, removing the fine concrete particles and leaving behind the exposed gravel and stone particles.
  2. Seeded – This method involves placing the gravel or crushed stone, by hand, into the surface of freshly-poured concrete. It is similar to planting seeds in the ground, except that just the surface of the stone is left sticking out the top of the concrete.
  3. Topping – Also known as a concrete overlay, this method is used to upgrade and existing concrete surface into a slip-resistant one. A fresh concrete batch is mixed and poured thinly on top of an old floor or path. The thin layer of concrete leaves the thicker stones exposed along the surface.
  4. Polished – This method is often used inside homes and is more decorative than functional. Instead of leaving the aggregate exposed with a textured surface, a grinder or sander is used to flatten the surface and make it level. Several layers of clear coat sealer are applied to create a shiny, polished surface.

As a general rule, the exposed gravel should always be at least two-thirds embedded in the concrete. This will prevent the stones from lifting and being removed from the surface, which would leave holes and large pits in the concrete. These pits can then collect dirt, water and soil, which can affect the durability of the floor.

Benefits of using exposed aggregate concrete surfaces

There are a number of reasons why people choose to use exposed aggregate surfaces in their homes and gardens. Firstly, it can look really nice if you use stones of various shapes and colours. Some homeowners like to match the colour of the exposed stones with the rest of their furniture. This makes it a customisable and aesthetic feature of a house.

Exposed aggregate surfaces are also very durable. They have the structural integrity of concrete and can last for 40 years or more. These surfaces are also highly-resistant to wear and tear and heavy traffic use. They can also handle exposure to the elements really well – sun, rain and hail have little impact on the strength and durability of these surfaces.

As with concrete floors, exposed aggregate surfaces require little maintenance besides sweeping and hosing with water. This makes them a cost-effective solution for floors and driveways. They don’t cost too much to install and they are certainly not expensive to maintain.

The main benefit, however, is the skid-resistance and added grip of the exposed aggregates. These surfaces are useful in wet conditions or around swimming pools. They ensure the safety of users, preventing slips and falls which could lead to serious injuries. Exposed aggregate concrete surfaces are safer than many other flooring materials, especially when wet.

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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 prevent dampness in a building

How to prevent dampness in a building

Dampness in a building may occur due to faulty construction, the use of poor-quality building materials or bad architectural design. Dampness affects the lifespan of a building or structure, but it also creates unhygienic conditions. Mold and fungi love to grow in damp conditions, so it is best to fix any signs of wet concrete as soon as possible.

The measures taken to prevent water from leaking into a roof is usually called waterproofing. The treatment given to a structure to keep its basement, floor and walls dry is called damp proofing. Some of the problems caused by dampness in a building include the disintegration of bricks, stones, tiles; the softening and crumbling of plaster; the corrosion of metals; the warping, buckling and rotting of timber; the presence of termites; deterioration to electrical fittings and the bleaching and flaking of paint with the formation of coloured patches.

What causes dampness in a building?

The absorption of moisture by building materials is one of the main causes of dampness. This can be caused by faulty structure design, bad workmanship or the use of defective structures or materials.

Sources of dampness in buildings include the rising of moisture through the foundation walling; splashing rainwater which rebounds after hitting the wall surface; penetration of rainwater through unprotected tops of walls, parapets or compound walls; gutters which allow rainwater to descend through the top supporting wall. In the case of buildings with flat roofs, inadequate roof slopes, improper rainwater pipe connections and defective junctions between roof slabs and parapet walls can also cause dampness.

How to prevent dampness in a building

1. Membrane Damp Proofing

This involves placing layers of water-repellant materials between the source of dampness and the structure. This type of material is commonly known as damp proof course (DPC). It could be made from materials like plastic or polythene sheets, cement-based concrete, bituminous felts or asphalt. Applying DPC in a basement is usually referred to as tanking and can prevent ground moisture from seeping into the concrete walls.

2. Integral Damp Proofing

This form of damp proofing involves adding certain waterproofing compounds to the concrete mix to increase its impermeability (resistance to absorbing moisture). The compounds made from sand, clay or lime help to fill the voids in concrete and make it waterproof. Compounds such as aluminium sulfate, calcium chlorides and alkaline silicates chemically react when mixed with concrete, producing waterproof concrete.

3. Surface Treatment

This type of treatment involves filling up the pores of the surfaces subjected to dampness. Water repellent metallic soaps such as calcium and aluminium oleates and stearates are often used for this purpose. Cement coating, transparent coatings, paints, varnishes and bituminous solutions also fall under this category. Another economical option for damp surface treatment is lime cement plaster. This effectively prevents dampness in walls as a result of rain.

4. Guniting

For this type of damp-proofing, a cement gun machine is used to deposit a layer of rich cement mortar over the surface. The surface must be completely cleaned of dirt, dust, grease or loose particles by wetting it properly. Cement and sand (or fine aggregates) are then fed into the machine. This mixture is finally shot onto the prepared surface under a pressure of 2 to 3 kg per square centimetre by holding the nozzle of the cement gun at a distance of 75 to 90 cm from the working surface.

5. Cavity Wall Construction

This form of damp-proofing consists of protecting the main wall of a building by an outer wall, leaving a cavity between the two walls. The cavity prevents moisture from spreading from the outer to the inner wall.

These five methods of damp-proofing will help to protect concrete structures from excess moisture, which can lead to mold, fungus, rot and damage to buildings. Contractors and homeowners must always inspect their buildings for any signs of stress and damage, such as dampness, which could affect the integrity and durability of the structure.

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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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What is concrete bleeding?

What is concrete bleeding?

Concrete bleeding is a problem that can affect any batch of concrete that has been improperly measured and mixed. It is the movement of water to the surface of the concrete after it has been poured. Water collects on the surface of a concrete slab or structure when the water-to-cement ratio of the mix is too high (when too much water has been added to the batch). 

Bad proportioning of materials in a concrete batch is the main cause of bleeding. Too much water causes the concrete to segregate – a phenomenon where the heavy aggregates sink to the bottom of the mix, leaving the cement, sand and water at the surface of the structure. The water then seeps to the surface of the slab or structure, which creates big problems on the resultant integrity of the concrete.

When the water travels to the surface of the structure, it carries the fine particles of cement with it. This leaves a deficiency of cement within the rest of the structure. Since cement is the main binding material, the rest of the structure dries without much bonding between materials. Bleeding causes a weak, crumbly and dry concrete structure that cannot support any weight.

Bleeding affects the workability of concrete

There are two categories of concrete bleeding; normal and excessive bleeding. These are determined by the amount of water lost through the surface of the concrete structure. Both normal and excessive bleeding can affect the final quality of the concrete and the overall durability of the structure.

Normal bleeding is that which often occurs in all concrete projects. When you see freshly-poured concrete, it will often have a very thin layer of water on its surface. This is nothing to worry about and can actually enhance the workability of the mixture. The improvement in workability makes it easier to pour and work with before it sets. It also gives the concrete a smooth finish.

Excessive bleeding is an abnormal amount of water loss through the surface of the concrete. The mixture is usually too wet before it is poured. Contractors should keep an eye on their concrete batch and add more cement or dry aggregate if they think the mixture is too runny. Excessive bleeding leads to a high loss of water and a dry, brittle concrete structure.

Concrete that has suffered from excessive bleeding may also have large voids in the centre of the structure where heavy aggregates have moved the fine particles out of their way as they sink. This creates air bubbles and empty pockets that can severely affect the strength and durability of the concrete.

The best way to prevent concrete bleeding is to use the required amount of water, as printed on the bag of cement. Contractors can also carry out a slump test to check the mixture has the correct ratio of dry to wet ingredients. Bleeding is a normal occurrence with concrete, but excessive bleeding creates long-term problems that cannot be easily repaired.

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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.

The importance of having a schedule for a construction project

The importance of having a schedule for a construction project

Construction projects are delicate operations that need to run on time in order to stay within the allocated budget. As soon as a project is delayed, it costs the contractors and building owners more money. Having a strict schedule is important as it keeps the project on time and allows all workers to know when to expect certain deliveries and deadlines.

A schedule is the process of assigning tasks, activities, milestones and deliveries to a construction project – basically setting deadlines that everyone will work towards meeting. The schedule will be used by all construction teams on the project, as well as the suppliers, to finish the building on time. It outlines the pace of work and how the tasks are supposed to be executed, but it also outlines how the team should deal with changes in the plan and delays. 

Why a construction schedule is important

The schedule is a vital planning document that outlines the following points:

  • It assigns dates and deadlines for the project’s activities.
  • Contractors can see whether these deadlines are obtainable or not and whether delays can be avoided.
  • The schedule allows contractors to estimate preliminary costs or tender bid estimates.
  • It can be used to plan the necessary resources (such as equipment, materials and labour) to meet the work tasks and deadlines.
  • The schedule provides a sequence of tasks so the project manager and all teams know what they need to be working on and what tasks they need to be prepared for.
  • It can improve the safety performance of a project by sequencing activities to ensure maximum protection for contractors.
  • It enables teams to set their own goals and work towards achieving these.
  • It outlines how delays can be dealt with in the smoothest and most efficient manner.
  • It eliminates problems of production bottlenecks, where many deadlines fall on the same day.
  • The schedule ensures that the project is completed at the soonest possible date.
  • It gives the building owners a target date by which their building should be ready for use.
  • It can be used post-completion to evaluate the contractors’ performances and to assign responsibility for any delays or overspending.

The building schedule is one of the most important documents for project managers, contractors and building owners. It keeps a project running on time and within budget. However, the schedule needs to be realistic and the estimations need to be achievable in order for it to be a valuable resource for 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.

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. 

___

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.

___

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.

Things to know about mortar for bricklaying

Things to know about mortar for bricklaying

The two most common types of mortar used for bricklaying are cement and lime mortar. They have different properties and strength characteristics, so it is important for contractors to which one to use for a project. LafargeHolcim Tanzania manufactures a few cement products that are suitable for use as mortar in brickwork. These are Tembo cement, TemboFundi and FastPlus.

Here are the things that contractors should know about mortar for bricklaying and brickwork construction:

1. Mortar does not affect the strength of brickwork – Various mortar mixes have different strengths, but they do not affect the overall strength of the brickwork. For example, mortars of mix ratios 1:6 and 1:4 have different strengths, but the brickwork will have the same strength in both cases, regardless. This is because the strength of brickwork depends on the bricks used, not the mortar.

2. An ideal mix ratio is 1:3 – When a mortar is mixed with one part cement (or lime) to three parts sand, it creates a dense mortar with fewer voids. This is an ideal mix ratio for most projects and general applications. A mix ratio richer than 1:3 is not used in bricklaying because of the high shrinkage rate. 

3. Lime mortar has a few advantages – Although lime mortar is generally weaker than cement mortar, it does have a few other advantages:

  • Lime mortar does not experience as much shrinkage as cement mortar.
  • Lime increases the workability and plasticity of the mortar mix.
  • Lime has good water retention and the mix does not dry out as quickly.
  • Lime can increase the volume of mortar by filling voids.
  • Lime makes the mortar more water-resistant and impervious to rain.

4. Lime mortar gains strength slowly – This is the reason why lime has a lower strength than cement. Lime mortar may develop early strength but it does not develop long-term strength as quickly as cement.

5. Cement-lime mortar ratios are important – When mixing cement and lime to form a hybrid mortar, it is important to know that leaner mixes (a ratio between 1:4 and 1:8) tend to be harsh when mixed with coarse sand. In these cases, plasticisers are recommended to help improve the workability of the mortar.

6. Sand affects the strength of mortar – The following factors of sand affect the strength of cement mortar, regardless of the ratio between cement and sand:

  • The grading of the sand.
  • The fineness or coarseness of the sand.
  • The angularity and roundness of the sand particles.
  • The fineness or coarseness of sand affects the plasticity of the mortar mix. Plasticity can also be increased by adding more cement to the ratio.
  • Fine sand results in a more workable mortar but more cement and water will be needed in the mix. This increases the water-cement ratio which reduces the strength of the mortar.

8. Curing is critical – The curing process is absolutely necessary to achieve the maximum strength of the mortar mix. Curing can take about seven days after bricklaying.

9. Common mistakes in brickwork mortar – The following are common mistakes that are made by contractors when making mortar mixes for bricklaying:

  • Not mixing the mortar properly.
  • Adding too much water to the mixture.
  • Laying a thick bed of mortar between bricks.
  • Using dry bricks that suck moisture out of the mortar.
  • Uneven joints between corners and bricks.
  • Voids in vertical joints between bricks.
  • Disturbance of bricks after laying.

10. Addition of pozzolana – Adding pozzolana to the mortar mix increases its strength and makes it more resistant to chemicals and harsh substances.

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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.

Applications of dry pack mortar

dry pack mortar on warehouse floor

Dry pack mortar is simply a mixture of cement, sand and water. Contractors often use special masonry cement to create dry pack mortar, such as LafargeHolcim Tanzania’s TemboFundi cement. The mixture is sometimes referred to as floor mud and it is used to create a bed of mortar for tile and brick placement. 

Other uses of dry pack mortar include shower installations and as a material for minor concrete repairs. This mixture is dry and sandy, hence its name. To make dry pack mortar, mix one part of masonry cement with four parts of sand and just enough water to produce a mortar that sticks together when moulded in the hand. If the mortar crumbles, there is not enough water; if it slumps, there is too much water.

Where to use dry pack mortar

This mixture has a variety of residential and commercial uses, as outlined below:

  • Used to prepare mortar beds
  • Used to level concrete surfaces
  • Used for floating shower bases and floors
  • Used to fill holes in concrete floors and walls

When using dry pack mortar to fill holes in concrete surfaces, it should be placed in layers of 1cm thickness and then compacted into the hole with a pole or a hammer. It is recommended to use a metal pole rather than a wooden one. Metal is better at compacting the mortar and will ensure a better bond with the underlying concrete surface.

Dry pack mortar offers numerous advantages. It can be used in dry and wet environments, inside or outside. It is also easy to mix, tamp, compact and slope, which makes repair jobs easy and efficient. Consider using dry pack mortar to make your net construction project a breeze.

___

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 countertops are better than granite or wood

Concrete countertops in the home

Not many people consider concrete as a building material for their kitchen countertops. Most people tend to choose wood because it is cheap, or granite because of its look. Concrete is actually the perfect material for a countertop because it offers the same cost-effectiveness as customisability as wood, as well as the strength and durability of granite.

Wooden countertops do not last as long as concrete and they can be susceptible to water damage. Granite, on the other hand, is highly expensive. Concrete offers the perfect balance between the two materials, which makes it an ideal material for countertops in most homes. Here are some more reasons why you should consider using concrete for your kitchen surfaces:

Concrete countertops are highly durable

Concrete is a strong building material, which is why it is the material of choice for most construction projects. Not only will concrete countertops last for decades, but they are also heat and scratch-resistant. Kitchen countertops usually take a beating; from hot pots to chopping with knives, the surface needs to be strong enough to resist these forces.

Wooden countertops can easily burn if a hot pan is placed on the surface. They can also get scratched easily by knives and kitchen trays. Wooden countertops are also easily stained by spilled food and drinks. Concrete is easy to clean and maintain, which adds to its durability.

Concrete is versatile and customisable

There are two basic types of concrete countertop; a precast slab or a concrete overlay that rests on top of a wooden base. Both of thee options allow for the concrete to be made into any shape that will fit any kitchen space. Concrete countertops can be poured into customised moulds that will fit the space available.

A concrete overlay also allows homeowners to simply pour concrete over the top of their existing countertops without having to go through the effort and expense of removing them first. This is not possible with granite as it is a dense and heavy surface – the underlying countertop would not be able to support the weight of the granite without reinforcement.

Concrete is affordable

Concrete is made from cement, sand and water – affordable materials that will create a strong surface when combined. Wood is the cheapest material, but it does not have the same advantages as concrete. Granite is a luxury material that few can afford, so it makes sense to use concrete – a material that is cost-effective and durable.

Concrete can be a fraction of the cost of granite, yet still offer the same benefits. It is an amazing substance to have in the kitchen and can also be coloured and decorated to resemble granite. Concrete is forgiving and can withstand the wear and tear that countertops endure in busy kitchens. It is also easy to maintain and can be a hygienic surface on which to prepare food. Consider using concrete for your countertops in order to exploit the advantages of both wood and granite, without the disadvantages of these two materials.

___

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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What is pozzolana and why is it used in cement?

Pozzolana is an ingredient in cement

One of the core ingredients of cement is pozzolana, or pozzolanic ash. It is a natural material that comes from volcanic ash and it contains silica, which gives pozzolana cementitious properties. This means that pozzolana can react with certain elements to form a hard, binding material.

Volcanic ash was first used by the ancient Greeks as a building material as early as 500 BC. However, it was the Romans that really pioneered the use of pozzolana as a binding agent to hold stones together. This allowed the Romans to build tall buildings and underwater structures, some of which still stand today, more than 2100 years later.

The substance is widely used in the manufacture of cement, including at LafargeHolcim Tanzania’s Tembo cement facility in Mbeya. Pozzolana has a number of physical properties that make it perfectly suited to creating cement, which we will outline below:

Properties of pozzolana

Pozzolana is used in cement for a number of reasons. When water is added to cement, it produces lime, or calcium hydroxide. Pozzolana reacts with this lime to form a strong bond with the other materials. On its own, lime does not contribute to the strength of concrete. The reaction between these two elements produces calcium silicate hydrate which is a strong bonding material.

By reacting with lime, pozzolana increases the strength of concrete. It also makes the concrete more dense, which is good for a structure’s durability. This reaction also decreases the efflorescence of concrete – the migration of salts to the surface of the concrete. Pozzolana is an important material for numerous reasons

Pozzolana can include the following elements:

  • Fly ash
  • Slag
  • Silica fume
  • Metakaolin
  • Vitrified calcium alumino-silicate

Of these elements, fly ash is the least reactive to lime and silica fume is the most reactive. This reaction determines the curing time of the concrete. These elements help to give cement it’s fine, powdery texture which is what makes it a good bonding agent when added to water and aggregates.

Other uses of pozzolana

Pozzolanic substances have a range of uses in construction, including the following:

  • Used in the manufacture of Portland Pozzolana cement (PPC).
  • Used as a soil-stabilisation material.
  • Used as a filler mineral in asphalt roads, helping to fill voids in the tar.
  • Used as a component in geopolymers, such as ceramics.
  • Used in roller-compacted concrete dams.
  • Used in the manufacture of concrete bricks.

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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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