How to prevent salt damage to your concrete structures

How to prevent salt damage to your concrete structures

Salt is a natural mineral that can sometimes end up in your concrete mixture. It can either be present in the sand and aggregate or it can end up in the concrete if you are building in a seaside environment. It appears as white streaks or powdery crystals on the surface of cured concrete.

The effects of salt can damage concrete if left untreated, especially large areas of walls and floor. The problem is worse near the sea where salt in the wave spray and in the air can affect concrete structures. Constant exposure to salt can cause problems for concrete structures.

How does salt damage concrete structures?

Concrete is an alkaline material. Any exposure to mildly acidic substances or those containing chlorides could break the bonds between the cement and aggregates. Salt is sodium chloride, so it can weaken concrete and make it brittle in a few ways:

  • Salt can lower the pH of concrete. This makes the pores in the surface bigger which can allow more moisture, water and other chemicals seep into the concrete.
  • Salt is hygroscopic which means that it attracts and absorbs water. It can retain water in concrete which leads to damage, rot and increased pressure inside the structure.
  • Salt speeds up the carbonation process. Under ideal conditions, contractors want the carbonation process to be slow so that the concrete can cure properly.
  • Salt introduces chlorides to the concrete. These chlorides seem up concrete corrosion and make the structure brittle.

How to treat salt damage in concrete

The first sign of salt in concrete will be white streaks or a white powder on the surface of the structure. To treat salt and prevent further damage, rinse the surface of the concrete with clean water. Scrub the salt away with a brush, leaving no white substance behind.

Next, apply a good sealer to the surface of the concrete to prevent salty moisture from entering the concrete. Sealers help to keep water and moisture out of the concrete pores. Ideally, you will want to use a sodium or lithium silicate densifier sealer as these chemically react with salt in the concrete to permanently protect the structure.

If you cannot get a proper concrete sealant, then apply a protective coating to the surface of the concrete. This could be a layer of plaster or a few coats of paint – ideally, both will help to form a protective coating that will prevent salty moisture from penetrating the surface of the concrete structure.

The best way to prevent salt damage, however, is to ensure that you use clean water when mixing the concrete and use sand from a freshwater river bed. Then, apply a sealer or protective coating as soon as the concrete has cured. Prevention is the best cure, so look after you concrete structures from the outset – especially in coastal environments.

___

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 fix foundation damage on your home

Foundation damage crack in concrete

Foundation damage to any building can occur in a number of ways, from weak soil to water damage. A concrete foundation can be a difficult structure to repair, so it’s best to look after your foundations and maintain them regularly. Keep an eye out for any signs of damage and fix them as soon as possible.

It is possible to repair foundation damage without having to demolish the building, but the process can be time-consuming and sometimes expensive. Foundations are the main support structure of a building. As such, they are an integral part of a building, acting like the skeleton upon which the rest of the structure is built.

Causes of foundation damage

Concrete foundations are strong and durable. However, other problems can occur that affect the strength of these structures. Most of the time, the type of soil and moisture in the ground are the cause of foundation damage. If the soil is saturated with water, it can move beneath the foundations or cause moisture damage to the concrete.

A building can be at risk of foundation damage if:

  • It is built on clay or sandy soil. 
  • If the soil around the foundations has inadequate drainage.
  • The region experiences extreme seasonal changes.
  • There is a major plumbing or water leak underneath the building.
  • Tree roots are growing too close to the foundations.
  • A flood, drought or earthquake affects the soil around the structure.

These problems cause the soil around the foundations to move. This movement is then directly transferred to the foundations themselves, which can cause cracks to form. This can cause the building to weaken and will affect its resale value. The longer foundation damage is left, the worse the resulting problems will become.

Signs of foundation damage

How can you tell if a building has foundation damage, especially if the foundations are below ground? These are the most common signs of stress and damage:

  • Walls leaning, rotating or cracking.
  • Separation of concrete around doors, windows and corners of walls.
  • Extended cracks up the side of the building.
  • Displaced mouldings.
  • Cracking and chipping of concrete where the building meets the ground.
  • Cracks along the floor of the building.
  • Uneven floors and misaligned internal features (like doors that won’t close).

The most common sign of foundation damage is the appearance of cracks on the interior or exterior of the building. Horizontal cracks or jagged cracks along brickwork are the most serious indication of foundation damage and should be addressed immediately.

Methods to repair concrete foundations

The most ideal repair methods are those that don’t require occupants to vacate the building or move their belongings. Luckily, with modern building techniques and technology, there are a few ways in which foundations can be fixed without causing disruption to home life or business.

The two most common solutions are slabjacking and hydraulic jacking. In a slabjacking repair, grout is pumped beneath the foundations to produce a lifting force that restores the foundations to their original elevation. In a hydraulic jacking repair, steel posts are driven into the unstable ground and hydraulic jacks are used to stabilise the concrete foundations.

These methods of repair are used to fix different types of foundation damage. Before deciding on a repair method, you will need to determine what is causing the foundation stress. Get a contractor to look at the cracks and correctly determine the best repair method to use. Slabjacking is suitable for smaller repair jobs whereas hydraulic jacking may be required for bigger problems, where the soil is fundamentally compromised.

Remember to inspect your foundations regularly to catch any issues early on. Regular maintenance will also avoid further problems caused by shifting soil, excess water in the ground and tree roots moving concrete foundations. Always fix any cracks as they appear and contact a professional contractor if you believe that your foundations are compromised.

___

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.

Tips for mixing and casting concrete slabs

Pouring a concrete slab

Casting a flat concrete slab may seem like an easy task, but there are some important details to remember that will make process safe and successful. One of the first things that contractors will learn on the job is how to pour a flat slab of concrete, whether it is for a floor, countertop or a base for an object.

Here are some things to consider before, during and after pouring concrete slabs. These tips will ensure that you don’t waste money or time during the process. Once you have built the wooden formwork and mixed the batch of concrete, remember the following points:

Safety is paramount

All contractors should wear appropriate safety gear when working with cement and concrete. Workers should have dust masks, goggles, gloves, boots and overalls. Appoint one employee to perform a quality check of the building materials and equipment before mixing the concrete. 

This will ensure that everything is in working order and that a high-quality batch of concrete is created. It will also ensure the safety of other contractors as faulty equipment, such as cement mixers, could lead to injury. This designated worker can also file safety reports and create quality checklists if needed.

Create a detailed batch report system

Before mixing the concrete, print out a detailed batch report that lists all the building materials needed and their quantities for each batch. When measuring out the sand, gravel, cement and water, put a tick beside each material. When adding the materials to the mixer, put another tick next to each item on the list.

This double-tick system will help you keep a detailed record of your building materials and see if there are any discrepancies or losses. It will also help you to accurately calculate how much concrete you will need to mix for the slabs. The batch report can be used for future reference so that you can easily recreate the slab with the correct quantities of materials.

Keep materials, tools and equipment nearby

It will help you to keep all of your building materials (sand, gravel, cement and water) near to the location where you will pour the concrete slabs. Also have all the necessary tools and equipment nearby. This will save time and effort when you need to quickly add some more materials to the concrete batch. It also makes it easier to carry heavy bags of cement or wheelbarrows of sand if they are stored close to the working site.

Pour multiple slabs from the same batch of concrete

If you are pouring several slabs at once, it is important to mix a large batch of concrete and use it to pour all the slabs, rather than mixing a small batch for each individual slab. This will ensure quality and consistency between all the slabs. Any variation in the ratios of wet and dry ingredients will easily be seen in the slabs. By mixing one batch of concrete, you will end up with identical slabs. 

Add materials to the mixer in the correct order

There is actually an ideal order in which building materials should be added to a cement mixer; sand and gravel go in first, followed by water and any admixtures. Next add any fibres and pozzolans. Lastly, the cement should be added gradually to the mixer.

The reason for following this order is simple; if you add cement first, followed by water, it can clump inside the mixer. Mixing the sand and gravel with water first ensures that all of the aggregates are wetted and dispersed. When the cement goes in last, it will combine nicely with the other materials to form a high-quality batch of concrete.

Some other points to remember

If you are hand-packing a stiff batch of concrete into a wooden form, make sure that the concrete goes into every edge and corner of the mould. If you are pouring a fluid mix of concrete, make sure that you release all the trapped air bubbles by tapping on the side of the formwork. 

If you are using steel rebar for reinforcing, make sure that it is suspended in the middle of the concrete batch and that no rebar stick out of the surface of the slab. These are some of the points to remember when pouring concrete slabs. Some of these details can be overlooked, which could affect the quality of the slab, so keep these tips in mind.

___

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.

What chemicals to use on concrete stains

What chemicals to use on concrete stains

While water is usually enough to remove dirt from concrete, you often need the help of chemicals to clean tough stains. From oil and grease to rust and graffiti, chemical cleaners will make the task of cleaning concrete much easier. 

Many contractors will recommend spraying the stain with the cleaning agent and leaving it to soak for about 15 minutes before using a high-pressure water spray to wash it away. Concrete is slightly alkaline because of the lime in the cement, so we suggest using an alkaline cleaning agent rather than an acidic one.

Oil and grease stains

One of the most common types of concrete stain is caused by oil. Parking lots, roads, pavements and garage floors are all victims of dripping oil from vehicles. Workshop and industrial floors can also suffer from grease stains. The best way to clean these surfaces is to use an alkaline degreaser with hot water.

The degreaser will improve the removal rate of these stains by emulsifying the oil and grease. The hot water will help to lift the oil from the concrete surface. Using a high-pressure water jet will also help to remove the tough stains in the pores of the concrete surface. Alkaline degreasers can also be used to clean soot and soil stains too.

Rust stains on concrete walls

Rust stains can either have a golden-brown appearance or a blue-green colour. They commonly occur on concrete walls around exposed pipes, metal brackets and bolts. Heavy rust stains can sometimes penetrate deep into the wall.

The golden-brown stains occur when steel oxidises and rusts, whereas the blue-green markings happen around copper water pipes. The best cleaning agents to use for these stains are the ones that contain oxalic acid. This chemical helps to break down the metals in the rust stain and make it easy to wash away with a hose or a water jet.

Graffiti on concrete walls

Graffiti on a wall can be very difficult to remove. The type of spray paint used will determine how much effort you need to clean it off. The best way to remove paint stains is to use a chemical stripper that contains a citrus-based solvent, methylene chloride or potassium hydroxide.

The citrus-based solvents are the least aggressive and safest cleaners, which is good for your concrete wall but not as effective at removing graffiti as the other two chemicals. Cleaning agents that contain potassium hydroxide are the best for paint stains. Spray them on the wall and allow it to soak for several hours before spraying the wall with a high-pressure hose. You will also need to spray an acid neutraliser on the wall after the cleaning process to protect the concrete from acid damage.

Another method of cleaning graffiti from a wall is to use a special attachment fitted to a water jet nozzle that feeds sand into the water stream. This essentially sandblasts the paint off the wall. While this method is safe and clean, it can damage the surface of the wall.

These tips will help you remove the most common types of stains from your concrete floors and walls. Water and a cleaning chemical will always give you the best results, but it is important to know what type of cleaning agent to use for each stain.

___

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 keep polished concrete shiny

Polished concrete floor

Polished concrete floors can be a beautiful look for any home, office or retail space. The polish adds durability to the concrete surface, protecting it from scratches and scrapes. However, polished concrete surfaces tend to lose their sheen over time, so they do require good maintenance.

Floors in high-traffic areas such as shops and commercial facilities should be polished regularly to keep them looking clean and shiny. However, these types of floors are easier to maintain than other decorative concrete surfaces as they do not require additional waxing or sealing.

Daily cleaning for polished concrete floors

You should try to sweep or mop polished floors once a day to remove any dirt that might scratch the polish. Dust, sand and dirt are abrasive and can remove the polish easily if they are not cleaned daily. Remember to use clean water and a neutral-pH detergent when mopping polished concrete floors.

Try to use a soft mop or cloth to clean the floor so that it does not scrape the dirt across the polished surface. The more traffic across the floor, the more often it should be cleaned. Here are some tips for keeping your concrete floor shiny:

  • Dust mop the floor every day with a microfiber cloth to keep dust and soil off the floor. These particles are abrasive and can ruin the shine of polished concrete.
  • If you are wet-mopping the floor, use clean water and a soft mop. Try to use a neutral-pH cleaner (one that is not acidic or alkaline) to protect the polish.
  • Clean spills from the floor as soon as you can to prevent them from becoming stains. Once a liquid is absorbed into the polish, it can become difficult to remove.
  • Give your detergents enough time to break down tough grime, such as grease or oil. These cleaning agents need to sit on the surface of the concrete floor for a few minutes to loosen the dirt.
  • Do not let the detergents dry on the surface as they can stain the polish themselves. Clean small areas at a time to prevent this from happening.

By following these tips, you will keep your polished floor looking clean and shiny, no matter how many people walk across the surface. A daily cleaning routine will increase the lifespan of your concrete floors and ensure that the polish lasts a long time.

___

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 improve productivity on a construction site

Building contractor productivity on site

Construction projects often fall behind schedule because of unforeseen issues. Site managers can minimise these delays by improving the efficiency and productivity of their teams. If contractors are able to work faster, then any delays will be reduced.

Whether a project encounters bad weather or absentee workers, the build needs to run as close to the original schedule as possible. Here are a few ways in which productivity can be improved on a construction site.

Clear communication is key

Without proper communication and direct lines of address, a project will fall behind schedule. Communication is key if the project is to run smoothly and on time. Contractors need to communicate with suppliers, architects, electricians, plumbers and their teams. 

Any changes to the schedule need to be communicated and regular meetings need to be held in order to distribute updates. When the lines of communication are clear and everyone knows what they need to be doing and when they need to be doing it, then projects become more productive.

Listen to feedback

Communication and feedback go hand-in-hand. Open lines of communication present an opportunity for feedback from team members. It is important to listen to one another and hear the opinions of those working on the project. Sometimes employees will be able to speed up a project if their concerns are addressed and they feel as if they are being listened to.

If they are worried about meeting deadlines or if their tools are not working properly, listen to their feedback and act accordingly. Have daily meetings with team members in order to address issues and increase productivity on-site.

Safety and training are vital

One of the biggest delayers of construction projects is job site injuries. Productivity is also affected when the team’s capacity is reduced due to injury and absent employees. Ensure that your team knows the safety rules and is properly trained in handling tools, equipment and building materials.

Before starting a project, make sure everyone knows what to do in an emergency. Ensure that every worker is trained and up-to-date with their knowledge. The more trained an employee is, the more skilled they are and the faster they will be able to work.

Set realistic targets

One of the best ways to improve on-site performance is to set achievable targets. A site manager should set realistic daily, weekly and monthly goals for their teams to work towards. If contractors can meet their targets, they will feel motivated and willing to push onwards.

Managers can devise plans that will help their teams reach their goals. Write down what steps need to be taken to improve productivity and stick to a plan. Note any tools and equipment that will be needed so that you can have them on-hand and ready. Also, consider any logistical issues that may hinder your goals and make sure that they are planned properly.

Keep an eye on your inventory

Another frustrating cause of delays is running out of building materials and supplies. Check your inventory once a week and order any materials or supplies that are running low. Get your employees to report any shortages as soon as they notice it. This will give you more time to contact suppliers and order new materials if needed.

It is also important to double-check your inventory and compare it to the original plan. If your supplies are running out faster than you initially thought, it can delay the project down the line.

Delegate tasks

As a team leader, it is important to know each person’s strengths and weaknesses. Delegate tasks to certain individuals that you know are competent. They will be able to handle the tasks quickly and professionally.

Giving employees a sense of responsibility can also help them to become more productive. Keep an eye on their performance and pull them off the task if they are not doing so well. There should be a good link between the management and the team, so delegating tasks is a good way to bridge the gap and give them a sense of pride in their work.

Reward team members that perform well

One of the easiest ways to encourage employees to work hard is to reward those that perform well. Offer incentives to employees that reach their goals on time – whether it is free lunch or a month-end bonus, rewards are well-received on construction sites. By offering rewards, you show your team that you are paying attention to their work and that productivity is rewarded.

Work with the right suppliers

This is an important step to note. Suppliers can make or break your project schedule. Ensure that you work with the right suppliers who are able to meet your delivery deadlines and align with your targets. Suppliers can easily boost productivity if they deliver materials on time.

LafargeHolcim Tanzania can offer safe delivery of cement, along with a number of value-added services. We ensure that our deliveries arrive on time and that our partners can rest assured of their deadlines being met.

___

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 strengthen existing concrete walls

Strengthen existing concrete walls

Sometimes old concrete walls need to be reinforced and strengthened to keep the structural integrity of a building. Walls should also be strengthened if you’re planning on adding more weight to the roof, either by building an upstairs extension or changing the roofing material. Some contractors even advise reinforcing walls in areas that are affected by high winds and ground tremors.

You can strengthen concrete walls in a variety of ways and by using different materials. The four most common methods include concrete jacketing, concrete replacement, retrofitting steel and by using fibre reinforced polymer (FRP) laminates. These methods are outlined below.

Concrete jacketing to strengthen walls

This traditional method of reinforcing walls involves adding a new layer of concrete to the existing wall in order to make it thicker and stronger. It is probably the most commonly used method. Additional steel rebar is placed between the new concrete and the existing wall for added strength. Contractors will make a grid of horizontal and vertical rebar which is then anchored to the existing wall. 

Concrete replacement

If a concrete wall is badly cracked or damaged, it may need to be replaced with a new batch. First, all loose concrete from the old wall needs to be scraped away and removed. Only structurally-sound concrete should be left behind. Any steel rebar needs to be checked and straightened if necessary.

Once the preparation work is done, wooden formwork can be assembled and erected. Fresh concrete can then be poured into the formwork and left to dry. After 24 hours, remove the formwork and allow the concrete wall to cure.

Retrofitting steel reinforcements

Existing concrete walls can be strengthened by retrofitting steel materials. This method does add a bit of weight to the walls but it can also be done with minimal disruption to anyone living or working inside the building. There are two types of steel materials that can be used with this method; steel plates and steel bracing.

Retrofitting with steel plates involves erecting flat sections of steel along the length of a wall. The steel increases the strength and stiffness of a wall, reinforcing it from the outside like a set of armour. The use of steel bracings is a lighter alternative to steel plates as it forms a steel skeleton along the wall. It performs the same function as steel plates, but the braces leave parts of the wall exposed. This is better for walls that don’t need so much reinforcement.

Fibre-reinforced polymer (FRP) laminates

This method is similar to steel reinforcement but it uses lightweight FRP laminates. FRP is strong and does not rust (unlike steel). Its light weight means that it is also easier to handle and install than steel. Like steel, the FRP laminates come in sheet form or rod form so it can be applied to a wall in the same ways as mentioned above.

These methods of making walls stronger have their advantages and disadvantages. They can all be used to repair damaged walls or to increase their load-bearing capabilities. Strengthening walls can allow contractors to build on top of walls and extend houses with extra floors.

___

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 salt finish a concrete floor

Salt finish concrete floors

A salt finish is a method of texturing a concrete floor for added grip and a different look. It works by sprinkling coarse rock salts on the surface of wet concrete and embedding them with a roller. Once the concrete dries and hardens, the salt crystals are then washed away with water to leave subtle dimples on the surface of the concrete.

Salt finishing gives a concrete surface added skid resistance and can also add a decorative appearance to floors and pavements. There are a few different ways to salt finish a concrete floor, but all of them require proper planning and execution in order to achieve the desired results.

The quality of the concrete and the salts will determine the finish achieved. The type of cement used will directly affect the performance and durability of the concrete surface, so we recommend using Tembo FastaPlus. Whether you want to salt finish a concrete floor or a driveway, you need to make sure that the ground is prepared and the concrete is poured properly before adding the salt crystals.

Prepare the floor for a salt finish

Once you have poured the concrete for the floor, pavement or driveway, take special care in the finishing process. Don’t overwork the surface as this can cause the concrete to shed moisture too quickly. Smooth the concrete surface and remove any excess concrete or water with a wooden float. This will give the surface of the concrete a fine and glossy finish.

Once the surface is smooth, leave the concrete to dry for a little bit. To test the concrete’s readiness for salting, press a finger onto the surface. If your finger can make a 5mm dent in the surface without leaving and concrete residue on your finger, then it is dry enough for the salt application.

Scatter the rock salt crystals over the concrete surface – the salt crystals should be between 3mm and 8mm in diameter. Try to evenly distribute the salt, using about 3kg of salt per 10 square metres. Press the salt into the concrete surface using a light roller or a trowel. The salt crystals should have half their diameter sticking out above the concrete surface. 

Remove the salt crystals

Leave the concrete to dry for 24 hours and then remove the salt with a broom and a hose pipe. The salt will dissolve when sprayed with water as salt is a soluble mineral. There is not enough water in concrete to completely dissolve the salt, that is why a hosepipe is needed.

When the salt is dissolved, it leaves small depressions in the concrete surface. These dimples give the surface extra grip and texture. It is advisable to apply a concrete sealer to the finished surface to give it a glossy look and to protect the new floor from wear and tear.

___

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 pour new concrete over an old concrete floor

New concrete floor

Old concrete floors can be replaced by new ones, simply by pouring freshly made concrete over the top. However, you will need to clean and prepare the old concrete surface first. If the old floor is badly damaged, you may have to break it up and lay a completely new floor. If the old floor is structurally sound and if fairly good condition, then new concrete can be poured on top.

Some repair work may require you to lay down some steel rebar to reinforce the new concrete floor. Make sure that you properly plan the pour so that you don’t waste time or money. Follow these steps to replace an old concrete floor with a new one by pouring fresh concrete over the top.

1. Clean old concrete surface

Before starting the repair job, you will need to clean the old floor. Sweep up any dust, dirt, sand or grass. Any dirt on the surface can affect the quality of the new floor. If the old concrete floor is a bit chipped, scrape it with a spade to dislodge any loose concrete flakes. Use a stiff-bristled broom to sweep up any concrete dust afterward. The floors can also be sprayed with a pressurised hose to loosen any stains or mud.

2. Make formworks

Pouring concrete over old floors still requires basic formwork to be made. Use timber and screws to make a wooden formwork that fits neatly around the old concrete surface. The form should extend above the existing concrete floor by the same thickness as the new floor.

Reinforce the form with wooden stakes or supports every one metre and make sure that the form is level. If there are any control joints on the old floor, mark their positions on the wooden form so that you can cut new ones on the new floor. If the concrete floor is surrounded by four walls, wooden forms will not be necessary (only at entry points such as doorways).

3. Place rebar

If you think that the floor needs reinforcement, cut some steel rebar to the right length. Look at the old floor and see where the cracks are located. The rebar can be placed across these areas to reinforce them. The rebar needs to be laid in a neat grid with 90-degree angles and fastened together with wire.

4. Saturate existing concrete surface with water

Before pouring the new concrete, hose down the existing floor to wet it thoroughly. This will prevent the existing floor from absorbing water from the new concrete. If the moisture inside the fresh concrete is absorbed by a dry floor, then the new concrete floor could crack and shrink.

5. Pour new concrete

Now it is finally time to pour the new concrete over the old floor. Tembo FastaPlus or SupaSet cement will be ideal for new concrete floors. Mix the cement with water, sand and crushed stone, according to the instructions on the back of the cement bag. Once the concrete is poured, tap the wooden forms to remove any trapped air inside the concrete. Run a metal pole through the new concrete mix to remove air bubbles and pack it tightly.

6. Finish new surface

Smooth the new concrete surface with a trowel and wooden float. In hot weather conditions, perform this smoothing process quickly as the concrete will dry quite fast. Once the surface no longer has any water on top, you can start to cut the new control joints at the locations you marked out earlier. This should be between four and twelve hours after pouring.

7. Leave to cure

Allow the new concrete floor to cure for about one week after pouring. Keep the surface damp by sprinkling water on it every few hours. If the concrete floor is exposed to sunlight or wind, place a plastic sheet over it to prevent rapid evaporation of moisture.

___

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 make a sloped edge on concrete floors

Sloped edge on concrete curb

A sloped edge on concrete can have safety and decorative aspects. It removes sharp edges of concrete and also enhances the look of floors and walls. A sloped edge can also make it easier to remove wooden formwork from concrete that has hardened. Also called a chamfered edge, these slopes prevent concrete from chipping or cracking at the corners.

There are two common ways to make a sloped edge; by using chamfer strips or by using chamfer edge tools.

1. Using chamfer strips

This method of sloping concrete edges is done before the concrete is even poured. Chamfer strips are placed into the corners of the wooden formwork or mould, along the edges. Chamfer strips come in a variety of sizes that determine the angle and width of the sloped edge. They are either made from rubber or wood. Concrete is poured into the formwork and the chamfer strips give it sloped edges from the start.

2. Using chamfer edge tools

This method of sloping edges uses specialised tools once the concrete has been poured and the surface water has dried off. The chamfer edge tools are capable of creating sloped edges of various sizes. This process requires skilled labour and a steady hand to make the concrete edge smooth and straight.

How to make a sloped edge on concrete with chamfer tools

  • Allow the concrete to set until there is no more water on its surface. This should take about 30 minutes from pouring and smoothing with a float.
  • Use the edging tool to bury any crushed stone below the surface of the concrete. Grab the handle of the tool and insert the lower edge of the seam between the edge of the concrete and formwork. Use the inner face of the formwork as a guide and run the tool back and forth using long strokes.
  • Repeat the above step with the chamfer tool but use light pressure to create a smooth and even edge. 
  • Leave the concrete to cure for two hours, or until a light swipe with a trowel does not scratch the surface.
  • Remove the formwork using gentle taps with a hammer.
  • Fill a bucket of water and dip a rubber float into the water. Use small strokes with the wet float to smooth the sloped edges. Dip the float into the water frequently for the best results.

___

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.