Tag: masonry

Concrete – Powerful, Durable and Versatile

Concrete Contractors Colorado Springs is so ubiquitous that we often don’t consider it a material. But it is powerful, durable, and versatile. No other material exemplifies the transformation of culture into economy as much as concrete. It spawned brutalist structures but also helped create the sleek, modernist buildings of Le Corbusier and Oscar Niemeyer.

Concrete

Concrete combines coarse and fine aggregates, mineral admixtures, water, cement paste, and sometimes fly ash. The cement serves as a binder, holding the other ingredients together. It also hardens to become a strong and durable material when it dries. In construction, it is poured into forms to create structures such as walls, floors, and roads. Getting the mix right before rushing is important to ensure a good result.

The mixing process is done either by hand or with machine. Hand mixing involves placing dry ingredients on a flat surface and adding water to form fresh concrete. Machine mixing is usually more efficient for larger productions, allowing the concrete to be discharged quickly.

Once the concrete is mixed, it must be transported to the construction site where it will be used. This can be accomplished in various ways depending on the quantity needed, the distances involved, and other project specifics. Large amounts are often transported by truck or poured out of a mixer into formwork for structural elements. Smaller quantities can be carried in a wheelbarrow, bucket, or toggle bag.

A quick field test to determine the consistency of concrete is to pick up a handful and squeeze it tightly. If the concrete is properly mixed, it will hold its shape and not crumble under pressure.

It is also important to note that concrete should be mixed for the correct duration. A long mixing time will lead to poor results. It is suggested that the proper mix should be aerated for 3 minutes to make sure all ingredients are evenly combined. Then, the concrete should be left to rest for 1 minute before checking again.

Some concrete producers have determined the proper mixing time by performing lab tests on cylinders and cubes. This process is called mix design and helps find the best proportions for a desired strength. Other researchers have tried to measure the homogeneity of concrete by analyzing the distribution of various solid constituents in the concrete as it was discharged from the mixer. Johansson found that a concrete mixture’s uniformity increased with the mixing duration up to a point and reached a plateau (see Fig. 5.2).

Concrete is one of the most indispensable building materials, and to make it last long, it needs to be placed correctly. In addition to ensuring that the mix is properly designed, batched, mixed, and transported, the site preparation process, formwork, and reinforcement placement are crucial to the success of a project.

During the preparation process, the job site must be cleared of obstructions, excavation work must be done to create a suitable foundation, grading and stabilizing the soil, and utilities and services must be connected to prepare for construction. Once these steps have been taken, the concrete can be placed.

Once the concrete has been mixed, it is pumped to the desired location on the job site in a controlled manner. Using the right equipment can help ensure that concrete is properly placed and there are no problems in this process. This is especially important if you are working on a large-scale concrete project that requires multiple substantial lifts to be placed quickly.

The equipment that is used to place concrete should be able to ensure that there is a virtually continuous flow during depositing without segregation of the different concrete ingredients. Ideally, the concrete should be placed in successive horizontal layers that are uniform in thickness and deposited before the previous layer stiffens to avoid the formation of cold joints or planes of weakness. It is also important to use efficient communication between the concrete pump operator and the team that is placing the concrete to prevent any mishaps that could compromise the quality of the finished product.

Once the concrete has been deposited, it is usually compacted mechanically to eliminate any entrapped air voids and ensure intimate, complete contact with the forms and reinforcement. Most concrete is now consolidated by the use of a powered internal vibrator, which can be adjusted to match the slump of the particular mix to minimize the amount of desirable entrained air that is lost during the consolidation process. For thin slabs, however, a mechanical surface vibrator may be more effective since it can be placed directly against the formwork and reinforcement.

The curing process gives concrete strength, durability, and long life. Curing occurs after concrete placement and finishing and involves maintaining the desired moisture and temperature conditions throughout the substantial section depth for extended periods. It also protects the concrete from environmental factors such as wind, sun, and rainfall that can influence surface hydration and thermal cracking.

The main function of curing is to maintain adequate water content in the concrete-section depth and to control the water loss from the surface of the concrete that can cause plastic shrinkage cracks. Curing is especially important in areas with high sunshine exposure or large surfaces compared to the depth, such as roads and airport pavements, canal linings, bridge decks, and cooling towers.

There are many ways to cure concrete, and each has its advantages. The most common methods include water, membrane, and insulating blanket curing. Water curing uses sprayers or sprinklers to moisten the concrete and prevent evaporation. Membrane curing uses a liquid membrane such as bitumen emulsion, rubber latex emulsion, or wax to form an effective barrier against water vapor. Insulating blanket curing is an economical way to maintain the moisture in concrete and reduce drying.

In addition to maintaining a constant moisture level, the concrete must be kept at a constant temperature throughout the concrete-section depth. This is crucial because the chemical reaction that forms the concrete is an exothermic process that produces heat. If the concrete gets too cold, the hydration process slows and may not occur at all. On the other hand, if the concrete becomes too hot, it can develop stress cracks because the hydration cannot keep up with the strain being applied to it.

Properly cured concrete is strong, durable, and resistant to abrasion, freezing, thawing, and deterioration from carbon dioxide, chloride, and other chemicals. Engineers and architects often specify a minimum seven-day curing period in concrete structures, such as slabs on grade, driveways, sidewalks, and foundations. This is important in ensuring the concrete meets the design requirements and withstands the intended loads.

Concrete is a very durable material that can withstand immense amounts of force. It is also one of the most widely used materials in construction because it can withstand harsh conditions like extreme weather and blazing fires. It can also be easily molded into several different shapes and sizes, making constructing large structures like tunnels, bridges, high-rise buildings, dams, and other infrastructure easy.

Although strong, it needs proper reinforcements to ensure its structural integrity is not compromised over time. Choosing the right type and percentage of reinforcements is important because it will have a significant effect on how much load can be resisted by the concrete. Reinforcement is added to the concrete during the mixing process, and it can also be incorporated in situ using a formwork or poured into place with a tremie or other equipment.

After the concrete has been poured, it must be allowed to cure for a specified amount of time. During this time, it must be protected from water and extreme heat. This is done because heat and wind can dry out the moisture necessary for hydration to occur, which will affect the concrete’s strength development. It is also important to prevent freezing because this can damage the crystalline structure of the hydrated cement paste.

The curing process can be made more efficient with the help of several additives. Air entraining agents are often used to add and entrap tiny air bubbles in the concrete, which can reduce damage caused by freeze-thaw cycles. These additives can reduce the time it takes for concrete to reach a satisfactory strength level, which is a critical factor in its durability.

Crystalline admixtures can be added to concrete during mixing to lower its permeability. These additives can fill capillary pores and micro-cracks to block pathways for water and waterborne contaminants. They can also create a permanent waterproof barrier by crystallizing to seal the surface of the concrete. Finally, pigments can be added to the concrete during mixing to change color.

The Importance of Masonry Repair

Brick chimneys, concrete basements, cement driveways, and stone porches add curb appeal to homes and boost resale value. But they also require regular maintenance to stay beautiful and functional for decades.

When Charleston Masonry is neglected, damage can cause safety hazards and detract from property values. Rather than treating the symptom, it’s important to address the root issue to prevent costly and inconvenient repairs.

Cracked bricks can be an indicator of serious structural issues. They are only sometimes the result of foundation settlement but can also be caused by soil issues, so it is important to inspect your brickwork regularly. While cracks can be unsightly, the good news is that they are usually easy to repair. However, it is important to understand that simply filling in the cracks won’t solve the underlying problem. The best thing you can do to prevent the cracks from getting worse is to have them repaired as soon as you notice them.

Hairline and stair-step cracks are common and not necessarily something to worry about, especially if they haven’t become too deep or wide. This is often the result of thermal expansion and contraction, which causes the brick to expand and contract at different rates. However, if the cracks are deeper and wider, they could be a sign of serious foundation problems.

It is also important to check for spider web cracks, which radiate from a central point. These are also typically a result of thermal expansion and contraction but can be caused by settling or other structural issues with your home.

If you notice these types of cracks, you should have a masonry contractor check the situation and determine the cause of the cracks. This is a serious issue that needs to be addressed immediately, as it can lead to structural instability and potential flooding.

A masonry repair contractor should be able to resolve these issues by removing the affected bricks, stabilizing the foundation, and installing push piers if necessary. In addition, they can resurface your brick walls and apply a breathable sealant to help prevent future moisture damage.

Some products are available for repairing these cracks, including mortar repair caulk and masonry fillers. These are available in most hardware stores and can be used to fill the cracks. It is important to ensure that any excess mortar is cleaned from the surrounding bricks and is misted with water daily for three days to allow the repair to cure slowly. It is also a good idea to tarp the area to protect it from rain.

Mortar joints are the critical element that holds brick and stone masonry together. If mortar cracks or crumbles, it must be chiseled out and new mortar troweled in, a process known as repointing. This is a very important job that, when done poorly, will compromise the integrity and appearance of your masonry. A professional mason is the best choice for this type of work because they have the tools and experience to do it correctly without damaging the brick.

Cracks in mortar are normal, but they should be repaired as soon as they become visible. Leaving them unattended will worsen the problem, and it is often impossible to restore the original integrity of the masonry structure when damage becomes severe.

The primary causes of cracked mortar are exposure to adverse weather conditions, expansion and contraction due to changes in temperature, and general material deterioration over time. These factors are compounded when water seeps into the core of the masonry and freezes, expands, and thaws again in cycles that cause abrasion and corrosion.

Although mortar is designed to be weaker structurally than the masonry to which it bonds, mortar joints tend to crack in response to movement in a wall, as well as from natural expansion and contraction of the masonry units themselves. These cracks can be filled with a masonry patch, but only after the old damaged material is removed and the area is cleaned thoroughly. New mortar cannot be used to cover up the existing damage because it will only exacerbate the problems.

The first step is to scrape the old mortar from the horizontal (bed) joints. This can be done with a hand hammer and cold chisel or a utility chisel. Be sure to protect yourself with a dust mask and safety goggles, and use caution when using an angle grinder, which can damage the faces of bricks. Once the bed joint mortar is removed, it is necessary to clean out the vertical (head) joints as well. Again, it is best to use a utility chisel to avoid damaging the bricks. After cleaning the head joints, it is necessary to mist the wall with a hose until it is thoroughly damp and starts to drip. This is a crucial step because dry brick will suck the moisture out of the new mortar, preventing it from curing properly.

Although brick is a strong and durable building material, it is not indestructible. Over time, any masonry structure will deteriorate and eventually require masonry repair work. The timeline for masonry repairs varies depending on the severity of the issue. Still, regularly scheduled inspections and timely repair of small issues help preserve the structural integrity and aesthetic appeal of masonry buildings.

The best way to prevent masonry deterioration is through proper maintenance and regular inspections from a professional contractor. This will help to identify a small problem before it becomes an expensive and time-consuming problem to resolve. Regular masonry maintenance includes cleaning, tuckpointing, and repairing joints and cracks in masonry walls and facades.

Historic masonry buildings are prone to different problems than newer buildings, so it is important to hire a professional who has extensive experience working with landmark masonry materials and systems. Thoughtfully designed masonry repair and restoration projects can help to extend the life of historic masonry buildings for future generations.

Differential movement between masonry materials is a common cause of cracking. For example, concrete masonry tends to shrink when exposed to moisture, and clay brick masonry may expand. This differential movement can lead to the formation of shrinkage and control cracks in masonry walls.

In some cases, these cracks can be repaired with helical bar grouting or with a masonry crack stitching system. While these methods of repairing cracks in brick walls are effective, they should be used with a full structural engineer’s repair specification that addresses the source of wall movement.

Stair-step cracks in the wall in a diagonal pattern indicate more significant structural problems and should be addressed by a structural engineering professional. These cracks can cause serious damage to the building if not addressed quickly.

The difference between repairing and restoring masonry is that masonry repairs are limited to removing damaged mortar and bricks from the face of the structure and filling in any gaps. At the same time, restoration is a more involved process that involves replacing the existing masonry with new materials. This means a restoration project will usually take longer than a repair project, as the original building material must be returned to match the existing structure.

Efflorescence is the crystalline deposit of salts on masonry surfaces such as brick, concrete, sandstone paving, and stucco. This material has a white or gray tint and can look like powder. Efflorescence isn’t dangerous and can be easily cleaned, but it can indicate a moisture problem that needs to be addressed.

Masonry in contact with soil can absorb water-containing soluble salts. Through capillary action, this water rises within the masonry and deposits the salts on or on the surface. This problem is more likely to occur during rainy or winter months when water can more easily penetrate the masonry. It can also be caused by improper protection of masonry materials during construction, which allows moisture to enter the building.

Improper insulation of basement walls can also contribute to the development of efflorescence. This issue must be identified and rectified as soon as possible to prevent damage to the interior of a home and health problems for its inhabitants.

Efflorescence can be prevented by impregnating hydrophobic sealant on all exposed masonry. This will prevent the absorption of moisture that contributes to the development of salt deposits. It’s also a good idea to install capillary breaks, such as polyethylene sheeting between the soil and the building material, to minimize the transfer of water and reduce the potential for the formation of efflorescence.

The simplest method for removing efflorescence is to wash the surface and scrub it with a soft brush. However, only clean water should ensure the masonry is not damaged. Pressurized water can sometimes remove or dissolve the efflorescence, but the masonry must be dried off quickly afterward. Otherwise, the soluble salts will be re-absorbed into the host masonry and can later reappear as more efflorescence.

For more serious cases of efflorescence, muriatic acid can be applied to the masonry. This substance can be purchased from most hardware stores, but it’s important to wear protective clothing, including rubber gloves and a mask when applying it. Baking soda should be used after application to neutralize the acid and avoid further discoloration of the masonry.

Navigation