The Difference Between Exterior and Interior Concrete Preparation

When mixing concrete, the goal is to achieve a product that has superior durability and maximum strength. Mixing the bags of concrete is not a difficult process, and when it is done properly it should last a lifetime. The trick is to get the exact ratio of mix and water, along with any additives, to ensure the concrete has the greatest strength you can coax from it.
It can be tricky to determine what the crucial point is. It takes some practice to look at the mix and know just the right amount of water has been added. If you use too much water, the concrete will be weak. If you use too little water, the particles contained within the mix are unable to bind together.
There is a difference between interior and exterior concrete preparation.
Interior Concrete Preparation
Bagged mix
Any hardware store, lumberyard, or home center should have a good variety of concrete mix. They generally come in bag sizes of between 60 and 80 pounds. Depending on the scope of your project, the different features you can find include fiber reinforced, high early strength, and fast setting. For most DIY fixes, it is perfectly fine to use a standard concrete mix.
The back of the bag is a good source of information. It should contain usage recommendations that allow you to decide whether you need to choose a special mix. For both interior and exterior jobs, the actual mixing process is the same. What changes are the additives, if any, that are found within the bag, and the ratios of ingredients.
Mix your own
To produce a mix of concrete with a psi of roughly 3,000, the ratios you will be working with are 3 parts of sand, 1-part cement, and 3 parts aggregates. To make a yard of concrete, you need 1,560 pounds of sand, 517 pounds of cement, 1,600 pounds of stone, and 34 gallons of water.
Most concrete projects can easily be completed with the above mixture. At four-inch thickness, your mixture should cover 80 square feet. A cubic yard of concrete with 4,000 psi will need some changes to the recipe.While the amount of stone stays the same, you will now need 1,450 pounds of sand, 611 pounds of cement, and 35 gallons of water.
When less sand and more cement is used, the final mixture is extremely strong, making it perfect for use in exterior projects like patios, driveways, sidewalks, commercial garages, and pool decks.
Mixing procedure
Once you have an appropriate container available for mixing, weigh out all the dry ingredients and add them into the bucket. Blend the ingredients together until they are all evenly distributed. If there are any clumps you are unable to break up, throw them out.
Start adding in the water and mix well after each addition. Be sure to scrape the bottom and sides of the container as well. Add more water as needed until the final mixture resembles cookie dough with no dry pockets.
Slump test
Whether you are using your concrete for indoor or outdoor use, a valuable tool for those new to the properties of cement is the slump test. Slump cones can be purchased wherever you buy the concrete, or you can simply use a plastic cup. Ideally, your mixture will have a slump of 4″ if it neither too soft or too stiff.
Using a pen, poke a hole in the bottom of a plastic cup. This will allow any trapped air to escape. Fill the cup with your concrete mix and pack it firmly. Turn the cement filled cup upside down on a flat, hard surface.
Use your hands to gently vibrate the cup off and away from the cement without stopping. Lastly, use a ruler to measure the slump to make sure it is about 4″.
Shotblasting and scarifiers
For large surfaces (usually exterior), shotblasting does three preparation jobs in one: stripping, cleaning, and profiling. Shotblasters are often the preferred choice because they leave surfaces dry and ready to work on, and they give the rough texture you are looking for.
Also referred to as milling machines or surface planers, scarifiers are more aggressive and quicker at removing concrete than a grinder. High-speed rotations of multi-tipped flails chip at the concrete until it falls away.
Preparing surfaces
If you are planning to restore or overlay existing concrete, the most critical step is preparing the surface correctly. When this step is skipped or done incorrectly, you will not get good results.
To achieve the proper bonding of coatings and concrete overlays, you need to determine the CSP (concrete surface profile). The scale goes from CSP 1 to CSP 9. The rule of thumb usually adhered to is that the thicker the topping or overlay is to be, the higher the profile number should be. To get numbers in the seven to nine range will generally require the use of scarifying or shotblasting.
There are three main steps in the surface preparation process: cleaning, roughening, and repairing. Both interior and exterior surfaces need to be properly cleaned before any work commences.
Cleaning
For exterior surfaces, and interior surfaces when indicated, one of the quickest ways to clean the concrete is with the use of a pressure washer outputting at least 3,000 psi. The soil level is what determines the type of cleaning method used.
When water pressure power just isn’t capable of removing all the grease, dust, and grime, there are several common chemicals strong enough to do the job, including oxalic acid based cleaners, chemical strippers, and alkaline degreasers.
Roughening
With the temperature extremes and varied weather conditions, exterior preparation requires more than just a run with the grinder and a vacuum to achieve the ultimate bond. Although the grinder and vacuum method is perfectly suited to most interior projects, especially when the area is small, exterior projects should follow the pattern of acid etch, neutralize, high-pressure wash, and a thorough rinse.
Unless the exterior surface you are working on has an existing sealer or coating, skip the grinding.
Repair
For both interior and exterior projects, it is essential to the result that broken pieces, holes, and cracks in the existing concrete are fixed. If they are not repaired before new concrete or decorative work is installed, the integrity of the project can be compromised, which can result in work lasting for far less time than it should.
Final thoughts
Both interior and exterior preparation and mixing are quite similar. The biggest differences are the CSP and cleaning methods used to get the area ready.
Since there is no foolproof rule, it may take some trial and error to get the correct ratio of chemicals and machinery that work the best together for your specialized requirements.

How Temperatures Affect Concrete Pours

Concrete Pours

Concrete and cement are two different things. Water, aggregate, and cement make concrete. Aggregate is typically rock, gravel or sand depending on the desired use of the concrete. Cement binds the water and aggregate together through the hydration process, a chemical reaction forming the durable solid we know as concrete.

Making cement starts by mixing finely ground limestone and clay, and heating the mixture to a high temperature. This process forms a powder made up primarily of calcium, silicate, alumina and iron oxide. Different combinations of these chemicals, together with additives create different types of cement, for various applications.

Cement for residential construction, civil engineering or specialized cement for harsher corrosive, underground or underwater environments, are examples.

You need to consider the temperature of the environment when you pour concrete to assure a quality final product.

The Hydration Process

The hydration process is the chemical reaction that uses water and the components of cement to form crystals that bond tightly with the aggregate. The process has an initial dormant stage during which the concrete can be worked and a final setting stage that cures and hardens the mixture into its permanent state. It is an exothermic reaction, meaning it produces heat. However, the temperature of the concrete affects it while it sets. Too high a temperatureand the chemical reaction speeds up, too low and it slows down. The result, concrete that is brittle with a significant loss of strength.

The Ideal Temperature to Pour

Ideal concrete, for standard use in residential construction, doesn’t freeze, is not affected by most chemicals,and is watertight and resistant to wear. For concrete to have these characteristics, it needs to cure at the proper temperatures. These are between 50 degrees and 77 degrees Fahrenheit.

Cold Temperatures

In concrete setting terms, colder weather is any time the temperature falls below or is expected to drop below 40 degrees Fahrenheit. However, it’s not the temperature of the ambient air that is important but the concrete itself, which needs to stay above 50 degrees Fahrenheit.

The critical issue with cold weather is that concrete can freeze before it sets, this results in a weak, granular concrete with a distinct lack of strength. Or the mix sets too slowly with the interaction between cement and water (the hydration process) slowing down or stopping altogether, again causing a weak structure.

The remedy is to shield or protect the concrete from the cold to allow it to set correctly. Adding hot water to the mix, or chemical accelerators like calcium chloride to speed up the hydration process are options. As is adding slightly more cement into the mix, which causes more heat during the setting process. Curing and insulating blankets can be used to keep the concrete warm and protected from the cold. As can other types of physical shields and heaters.

Preparation is important too. Never set concrete on the frozen ground, and remove all snow and ice from areas surrounding or in contact with the mix. Always thaw frozen ground first by using heat pipes and blankets.

Lastly continuously check the temperature of the concrete with a pocket or infrared thermometer. It needs to be kept above 50 degrees Fahrenheit to set correctly.

Hot Temperatures

In hot weather, the temperature of the concrete needs to be kept below 77 degrees Fahrenheit. Ambient temperatures of 90 degrees Fahrenheit or higher can cause concrete temperatures to be too hot, requiring precautionary measures.

When temperatures are too hot, the hydration process is speeded up, resulting in a weaker bond.
Precautionary measures include adding cold water to the mixture, cooling aggregates before mixing, shielding the concrete from direct heat using heat and temperature shields or fogging the area directly above the mix. Additionally, chemical additives can slow the setting process, assisting the curing of concrete in hot weather.
Just as for cold weather, preparation is essential. Wet the subgrade and all areas to come into contact with the concrete. Wetting needs to be substantial, enough to make sure water is not absorbed from the mix into the subgrade, leading to cracking. Saturate at least four inches of the subgrade to stop water absorption from the concrete while it is setting.

Again, check temperatures regularly and adjust your precautionary measures to maintain an optimized temperature for the concrete.

Summary

Concretes three main ingredients, water, aggregate, and cement set into a solid through a chemical process called the hydration reaction. This reaction uses water to form crystals with the cement that bond to the aggregate, ultimately creating a bulky and robust solid, the concrete we all know.

Just like all chemical reactions, success requires the right conditions. And in the case of concrete, the temperature is an essential factor. Temperatures between 50 degrees 77 degrees Fahrenheitare ideal for concrete to set. Outside these ranges, precautionary measures must be taken, to ensure a stable and robust concrete.

Famous Roman and Italian Concrete Buildings

Italian Concrete Buildings

Nobody can argue with the fact that if you are looking for master builders who used concrete, one needs to look no further than the ancient Romans. The Italians maintained this concrete tradition through the Renaissance and beyond.

Regardless of the wear and tear, they have endured over the years, construction of aqueducts, roads, and temples completed during Roman times remain visible today.

Historical mentions

Ancient concrete is referenced many times in history, including in the writings of Pliny the Elder, a famous Roman scholar who died in A.D. 79 during the eruption of Mt. Vesuvius. Pliny was quick to point out that the best concrete was made from volcanic ash, and it could be found in the Gulf of Naples area, especially in the area surrounding the town of Pozzuoli.

Used in construction projects from the latter part of the Roman Republic until the Roman Empire faded, the secret behind the durability of Roman concrete is the incorporation of volcanic ash, which naturally stopped cracks from spreading.

Typically faced with brick or stone, Roman concrete was often laid, not poured. Waterside and bridge construction was made easier by the fact that some of the concrete they used could be set underneath the water. Although there is no definitive answer to when they first developed their concrete, widespread use has been confirmed as far back as 150 B.C.

Anyone who has ever visited Rome has no doubt been dumbfounded by the enduring beauty of buildings erect centuries ago. Some of the world’s most famous buildings capable of standing the test of time are located here, and all of them should be on the must-see list if you are lucky enough to embark on a trip to Rome.

The Pantheon

There was no steel added into the concrete the Ancient Romans used, but even without the reinforcing, the Pantheon is likely the greatest example of Roman masonry capabilities. Built more than 2,000 years ago, the Pantheon is the largest unreinforced concrete dome in the world.

Formerly a temple, the circular building is used now as a church. A portico of gigantic Corinthian columns made from granite stands underneath a pediment. Linking the porch to the rotunda is a rectangular vestibule. The opening at the top of the dome is the same distance to the ground as the interior circular diameter, 142 feet.

Altaredella Patria

Built in remembrance of Victor Emmanuel, unified Italy’s first king, the monument was designed in 1885 by Giuseppe Sacconi. Situated between Piazza Venezia and Capitoline Hill, the massive building is 70 meters high and 135 meters wide. Offering a stunning 360° view of Rome from above, the panoramic elevator gives the opportunity to see just how beautiful Rome looks.

At the base of the building is the Italian Reunification museum, and an unknown soldier’s tomb is located within Altaredella Patria. There were eleven unidentified remains after WWI, and one set of remains were chosen to be laid to rest in the tomb.

The Palazzo Montecitorio

This Roman palace was designed for the nephew of Pope Gregory XV, Cardinal Ludovico Ludovisi, by Gian Lorenzo Bernini. With Pope Gregory’s death, construction was halted until the papacy of Pope Innocent XII. Architect Carlo Fontana took over the construction and completed the building after making some modifications to the original plans.

An excavated obelisk was installed in 1789 by Pius VI. When Rome became the capital of Italy in 1870, Palazzo Montecitorio became the headquarters of the Chamber of Deputies.

Curia Julia

Potentially the oldest surviving building in Rome, Curia Julia was initially constructed as a temple. Originally named Curia Cornelia, the spacewas converted into a meeting place. In 44 B.C., the name was changed to Curia Julia out of respect to Julius Caesar.

There are two parts to the Curia, the Forum Romanum, and the comitium. The comitium was used as both a meeting place and court, while the Forum was a place of worship. Along with the colorful floor, another interesting feature of the Curia is the Altar of Victory.

St. Peter’s Basilica

Without a doubt, one of the most famous buildings in the world, St. Peter’s Basilica is a church located within Vatican City. Although it is the largest church in the world, it is not the Catholic church’s mother church like many assume. However, it is still regarded as being one of the holiest shrines known to the Catholic religion.

Said to be the burial site of the first Pope, and St. Peter, the Basilica is the site of many liturgical functions and pilgrimages held throughout the year.

Final thoughts

The buildings listed above are just a small sampling of what can be found in Rome. Everywhere you look, you will findamazing examples of the true artistry the Ancient Romans left as a legacy. Lovers of architecture will find Rome has something new to be discovered around every corner.

Best Concrete Curing System

Best Concrete Curing System
 

The curing or setting of concrete is an often misunderstood process. As concrete is wet when it is mixed and poured, many believe curing is a drying process that strengthens and sets the mixture in place. However, maintaining adequate moisture levels during the curing process is essential, with premature drying often leading to unwanted cracking.

The curing of concrete is a hydration process which takes time. By controlling temperature and humidity levels, you can help to create the ideal environment and optimize the hardness and strength of concrete.

Optimal conditions for concrete curing

As well as leading to cracking, improperly cured concrete is often weaker, less resistant to abrasion and can suffer from scaling. Concrete exposed to the elements can be particularly susceptible to these problems. Drying winds can reduce moisture levels, and fluctuating temperatures affect optimal curing conditions.

The strength of concrete increases over time, and it can continue to strengthen over decades. Around 90% of the strength, however, is typically achieved during the first four weeks, with the first three days of hardening being most critical. It is therefore essential to ensure the best curing conditions for concrete during this early phase, and there are several different curing systems to choose from.

But which system is best for you? Below we will describe some of the different curing systems available and their respective areas of use.

Curing of concrete specimens

Laboratories often require the curing of individual concrete specimens. Specific standards are set by the ASTM and AASHTO, along with recommendations for accepted curing methods. Curing tanks and moisture rooms are two such methods, each with their specific requirements. A comparison of the two will help you to decide which is most suitable to your situation.

Curing tanks

Curing tanks are one of the simplest and least expensive solutions for the controlled curing of concrete specimens. Water storage tanks such as those used for livestock feeding can effectively hold several smaller concrete specimens. This makes them perfect for shorter-term or temporary applications, or where space is limited.

Curing tanks are filled with calcium hydroxide-saturated water, which maintains moisture levels around the specimens. The calcium hydroxide prevents leaching of this chemical into the water. Additional equipment is then used to maintain optimal temperature levels in the water – monitoring, circulating and heating it as necessary. This ideal temperature is 23.0±2.0°C (73.4±3.5°F). They can even be interconnected to increase their capacity and the efficiency of the temperature regulation system.

Curing tanks are low-maintenance and easy-to-assemble yet provide all the conditions necessary for optimal curing of concrete specimens. Spillages from the tanks can occur, however, and the chemicals in the water prevent the specimens from being handled without protective gloves. The large surface area of water exposed can also lead to humidification of the rooms in which they are housed.

Moisture room

A more advanced solution for the curing of concrete specimens is a moisture room; a room made from moisture resistant materials in which temperature and humidity levels can be maintained. These can be pre-fabricated units or can be constructed in situ to the required size. This allows for the simultaneous curing of larger and greater quantities of specimens.

According to specifications humidity levels in a moisture room must be kept at or above 95% relative humidity. There are various systems for creating the inside atmosphere in a moisture room. One way is to use fogging humidifiers in combination with temperature regulation equipment to maintain levels. As with curing tanks, this temperature is 23.0±2.0°C (73.4±3.5°F).

A more advanced system involves atomizing spray heads which release temperature-controlled water into the room, providing both heat and humidity at the same time. Both systems are likely to incorporate an externally mounted control panel which regulates the temperature and humidity in the room. This allows for easy monitoring of the curing specimens.

Moisture rooms allow for easier and more effective storage of specimens. By using racks or shelving the specimens can be maximally exposed to the humid air. Organization and handling are also much easier than in curing tanks. Moisture rooms, therefore, allow for more effective curing of greater quantities of specimens but can be more expensive to build and maintain.

Final Thoughts

Which curing system you choose ultimately depends on your circumstances. If only a few specimens are to be cured, or you only require a temporary installation, then curing tanks will likely provide the most cost-effective solution without sacrificing on quality. When larger or a great number of individual specimens are to be cured, it may be necessary to take advantage of a moisture room’s greater capacity. For longer-term applications, the opportunities for more effective organization and easier handling can also make moisture rooms an excellent choice.

 
 
 
 

Concrete vs Steel

High-rise buildings dominate the skylines of our cities, and in the race to have the highest or the most modern, the boundaries of architectural engineering are pushed even further.
The materials that make this possible – concrete and steel, each have their strengths and weaknesses. So, which is the better material?
Safety Considerations
Safety Considerations
Concrete
The concrete industry has always maintained that concrete is safer than steel. It requires no additional fireproofing to meet fire codes and has performed well during natural disasters.
Buildings made of cast-in-place reinforced concrete can withstand winds of more than 200 miles an hour and can withstand flying debris.
Cast-in-place concrete provides very good resistance to impacts and explosions.
It can resist extreme temperatures from fires without losing its structural integrity.
Steel
Reports issued recently by the National Institute of Standards and Technology show the reduced structural integrity of steel was to blame for the collapse of the twin towers in NYC. The fierceness of the jet-fuelled fires contributed to the collapse. With measures such as spray-on fireproofing, buildings made of structural steel are capable of withstanding greater temperatures.
The strength of steel, and its ductility, along with design and engineering, make it a good choice in areas of seismic activity. It can bend without breaking in high winds.
Design
Concrete
You can create and shape anything out of concrete, making advanced design possibilities a reality.
Concrete has the advantage of offering extra space possibilities. Cast-in-place reinforced concrete can give more rentable space, due to the lower floor-to-floor heights. Donald Trump’s architects switched from steel to concrete so they could add two extra stories to the new building at the former Chicago Sun-Times site.
Steel
Steel remains the popular choice for office and multifamily developers. Use of girder slab, castellated beam construction, and staggered truss enables much lower floor-to-floor heights than expected in structural steel buildings.
Steel has the highest strength-to-weight ratio of any construction material.
Cost Considerations
Concrete
Prices of construction material have increased, but the cost of ready-mix concrete has remained stable.
Insurance companies look favorably on cast-in-place reinforced concrete buildings because the safety and structural integrity reduce liability on their part. Owners and developers of such buildings can save nearly 25% annually on the costs of property insurance.
Steel
Structural steel represents less than 20% of all the steel used in building construction. The increase in costs of the structural framing system represents less than 2% of the 10% increase in project costs.
 
Costs for concrete framing systems have gone up equivalently to the costs of a steel framing system, despite what concrete experts say, according to John P. Cross, vice president of the American Institute of Steel Construction in Chicago.
Environmental Impact
Concrete
Concrete is often locally sourced and needs less energy to transport to construction sites.
Rebar for concrete is often made from recycled steel.
At the end of its life, concrete can be crushed and recycled, but it can’t be used for new building concrete, whereas steel can.
Steel
85% of steel is recycled, according to the British publication Building.
New steel made from scrap uses about one-third of the energy necessary to make steel from virgin materials.
Steel fabrication is often completed at a significant distance from the construction site, which increases the use of energy needed to transport it.
Construction Scheduling
Concrete
Buildings with concrete can almost always be constructed faster – sometimes twice as fast, according to Alfred G. Gerosa, president of the Concrete Alliance Inc, in New York City.
On a 2-day cycle, workers can pour up to 20,000 square feet of floor space every two days.
Steel
While steel can’t beat concrete’s 2-day turnaround; it does provide benefits of its own. John P. Cross says he believes structural steel framing systems are the way of the future, and they result in a faster construction schedule.
CAD programs can pass their information straight through a database as a 3-D model, and send it to detailing and shop floor fabrication programs. These productivity increases help to ensure the future of steel as a viable construction material.

Properties of Reinforced Concrete

Reinforced concrete refers to concrete that has reinforcements embedded inside. These reinforcements are necessary because concrete cannot withstand tension and shear stresses encountered in the everyday operation of the structure. Environmental factors such as strong winds may cause large vibrations of a concrete structure and possible damage if it does not have reinforcement material inside.
Although concrete has existed for thousands of years, reinforced concrete did not appear until recently. In fact, reinforced concrete was first used by Jean-Louis Lambot in 1848, when he embedded iron bars and wire mesh in some concrete rowboats.
Today, reinforced concrete is found on most construction sites.
Reinforced Concrete
Why Use Reinforcements?
The invention of reinforced concrete in the 19th century revolutionized the construction industry. By placing steel bars and plates inside the concrete, the ability of the concrete to sustain heavier loads greatly increased. This invention allowed for the construction of high-rise buildings.
When you embed reinforcements in the concrete, the concrete and the reinforcing material work together to resist any applied forces. Compressive and tensile forces push and pull on the concrete over its working lifespan.
Today, reinforced concrete is used in almost all construction projects. It has also surpassed wood to become the most commonly used construction material.
Steel Reinforced Concrete
All kinds of materials can be used to reinforce concrete. But steel is the most popular choice due to its ability to expand and contract at the same rate as the concrete. This feature ensures the steel will not crack the concrete during fluctuations in temperature.
Reinforcing steel is usually embedded in the concrete in the form of steel rods, steel bars, or steel meshes. The steel is tied together to make a skeletal structure before the concrete is poured over top.
After the concrete sets, the newly created reinforced concrete will have superior resisting properties. It can withstand high tensile and compressive stresses for long periods.
Fiber Reinforced Concrete
Fibers are a new type of reinforcement used to make reinforced concrete. These fibers are rated by their aspect ratio, which is a ratio of the fibers’ lengths to its diameter. They are randomly dispersed throughout the concrete and stirred well to create a uniform mix.
The most common material used to make the fibers include glass, synthetic, and even steel. Other materials used to make the fibers that are not so common include asbestos, which is economical, and carbon, which has great mechanical properties.
Properties of Reinforced Concrete
Concrete by itself is an aggregate mixture of cement and stone. This mixture does not stick together when dry but forms a rigid structure when water is added and then stirred.
With the addition of steel inside the concrete, the newly formed reinforced concrete has a coefficient of thermal expansion that is similar with that of both the steel and the concrete. As a result, internal stresses resulting from variations in the environmental temperature are almost non-existent.
Additionally, when the concrete cement hardens, it corresponds to the surface features of the steel. This allows the stresses acting around the reinforced concrete to be efficiently spread between the two materials.
Another desirable property of reinforced concrete is the development of a thin film on the surface of the steel. This occurs due to the alkaline environment caused by lime. As a result, the steel becomes extra-resistant to corrosion as moisture cannot penetrate this layer of lime easily.
Problems with Reinforced Concrete
The most common problem associated with reinforced concrete is corrosion. In the presence of moisture, the embedded steel may corrode and chip away. Corrosion results in extensive damage to the inner core of the concrete. For large structures such as high-rises, bridges, and dams, this presents a serious problem, as the failure of such a large structure would be catastrophic.
Techniques have been developed to detect the extent of the corrosion in the embedded steel. This information can be used to calculate the lifespan of large reinforced concrete structures so they can be rebuilt at the end of their life cycle.
Final Thoughts
Reinforced concrete refers to concrete that has embedded materials inside it. This material is often steel or fiber, and they work together to increase the tensile and compressive strength of the composite structure. As a result, reinforced concrete has superior qualities compared to plain concrete. Reinforcement makes them an attractive option for building projects, and they can be found on almost every construction site today.

Types of Concrete Foundations

For a vast number of people, the construction industry is almost a complete mystery. Even if you walk by construction sites every day of your life, the chances are if you haven’t worked in construction – or don’t know someone who has – the whole thing will remain a closed book.
However, the world of construction is a fascinating place, and well worth knowing about even for people who have never swung a hammer in their lives. As for people with an interest in DIY, or who simply want to get to know the building they live in a little better, knowledge of construction can be invaluable – and one of the best places to start with that is with the foundation.
There are as many foundations as there are buildings. The specific needs and characteristics of every home and every construction site are different, so naturally, the foundations will vary hugely in every case.
However, in most cases foundations for different buildings will fall into one of a few different categories, depending on the building, the ground, and the climate. Here are some of the main categories of concrete foundation used in most residential and commercial buildings.
Types of Concrete Foundations
Slab-on-Grade Foundation
In a slab-on-grade foundation setup, rather than being supported by a footing or another intermediary layer, the concrete foundation slab is poured directly onto the ground. The edges of the slab are designed to be significantly thicker than the rest, which makes for an extremely strong base of support for the home.
The fact that the concrete is in direct contact with the earth means this foundation type is not best-suited to all areas and soil conditions. Generally, it is best used in areas with warmer, drier climates, where the ground is not likely to freeze. It may also make the property more vulnerable to flood damage.
On the other hand, it is cheap and extremely stable, and less vulnerable to certain kinds of environmental damage, including infestations by pests such as termites.
Variations on direct slab-on-grade foundations include the floating slab formation – in which the slab is not in direct contact with the ground, but is secured by concrete layers several millimeters above it – and frost-protected slab-on-grade. Frost-protected foundations are fundamentally like direct slab-on-grade, but the concrete slab is insulated with two layers of polystyrene sheeting. This foundation style is more effective than slab-on-grade for colder climates, although the structure itself will still require insulation in winter months, and it is both tough and cost-effective.
Raft Foundation
Raft Foundation
Raft foundations, also sometimes known as mat foundations, are similar in some respects to slab-on-grade foundations, in that the structure ultimately rests on a single concrete slab.
However, unlike slab-on-grade foundations, in which the base slab only supports the weight of the lower part of the dwelling, raft foundations are designed to support the load of the entire structure. Columns transfer the weight from upper floors, while the slab itself supports the lower part of the building. The mat can also be reinforced by using beams or ribs built directly into the foundation.
Raft foundations are used particularly when the soil is especially poor-quality regarding load bearing. They are also ideal for sites with uncertain sub-soil water behavior, as the concrete mat itself is relatively easy to waterproof when compared to separate spread footing foundations.
T-Shaped Foundation
T-shaped foundations, also known as a spread footing foundation, are common in many homes and other residential buildings. As the name suggests, spread footing foundations are significantly wider at the base, to provide more stability and help distribute the weight of the load-bearing foundation wall more effectively.
T-shaped foundations are frequently used in cold regions and areas where the ground is particularly likely to freeze during the winter. The footing is built below the frost line, the foundation walls are constructed and placed, and the concrete slab is subsequently poured on.
T-shaped foundations are ideal for homes with a basement, and for small- to medium-sized buildings in locations where the soil is in moderate to good condition. They’re also relatively cheap and simple regarding construction, at least when compared with other foundation types.
Conclusion
Depending on the type of building you’re dealing with, foundations will vary considerably. For larger structures, such as skyscrapers, a far deeper foundation is necessary than with residential properties. This type of foundation may incorporate shafts, piles, caissons, or earth-stabilized columns to dig into the subsoil layer and provide extra stability for the larger structure. Other larger structures may have a monopile foundation, which uses a single massive structure driven to a significant depth to provide stability.
Whatever the foundation type you’re dealing with, the sheer variety demonstrates the level of experience and skill on offer in the construction and engineering communities. Concrete, after all, is a tricky business – it takes a delicate balance and a light touch.

What Is Soil Cement?

Soil Cement
Most people know cement from its common use in concrete. This integral construction material is used in almost all modern buildings. What most people don’t know is that cement has many other surprising applications. Soil cement is an interesting example of the versatile ways cement can be used.
Soil cement is made from a mix of soil and water with regular Portland cement. Portland cement is the most common variety of cement used in modern construction and is used in most concrete production.
Soil cement has a variety of uses. It has a high level of compressive strength, making it useful for bearing loads. It is often used in road construction and as protection for pipes.
Soil Cement Versus Concrete
Soil cement and traditional concrete have some similarities in the way they are produced and the components used to make them. The subtle differences in material and production, however, are enough to produce very different products with different applications and costs.
Traditional concrete is made from a mix of rocky aggregate, cement, and water. The wet cement coats the pieces of aggregate, gluing them together into the hardened final product. Concrete is known for its usefulness and versatility in construction, particularly in large structures or buildings.
Soil cement, however, is made from a blend of soil, cement, and water. The rocky limestone aggregate commonly used in concrete is replaced with soil. The soil used in the production of soil cement can be a number of materials, such as gravel, sand, or even waste material from quarries.  Less cement is used in the production of soil cement than in the production of regular concrete.
The use of cheaper materials and a relatively low amount of cement make soil cement cheaper to produce than traditional concrete. However, the relative lack of Portland cement used in its production can make soil cement more brittle than traditional concrete, though it has a high compressive strength. Due to the difference in strength and texture, concrete and soil cement have very different practical applications.
How Soil Cement Is Produced
Soil cement is produced by mixing cement, soil, and water in a cement mixer. The water allows the cement powder to bond with the soil aggregate.
The paste that is produced by this process is then compressed. The compression of the paste allows the relatively low amount of cement used to be as efficient in its binding as possible. Like traditional concrete, the paste is spread and dried, forming the finished product.
The relative lack of cement and the use of soil as an aggregate allow for more material to be produced at a lower cost. The result is a product that retains some of the heterogeneous nature of the soil aggregate, but contains much of the strength and functional versatility of traditional concrete.
Soil Cement Types and Usage
The most common type of soil cement is Soil Cement Base, a variety often used as a cost-efficient base for roads. This type of soil cement is spread as a base layer beneath future roadways. It is then usually covered with layers of asphalt concrete to protect the base from water and erosion. The cost-efficiency and durability of soil cement has led to its widespread use in large roadways and parking lots.
Cement Modified Soil is the second type of soil cement. It involves the modification of regular soil with an even smaller amount of cement. This type of soil cement retains much of the original texture of soil.
Cement Modified Soil is used for making low-quality soil more useful for construction and engineering. Cement Modified Soil can be quite versatile in that different ratios of cement and soil allow for a wide variety of textures and consistencies.
The third type of soil cement has an unusual and fascinating practical application. Acrylic copolymer is a type of soil cement that was developed for military use. When applied directly to sand or soil it hardens the ground into a makeshift surface that could allow for foot or vehicular traffic.
Using the already-present soil of a region to make roadways is a revolutionary and potentially cost-efficient idea. This technology allows for the construction of functional roads and surfaces in remote areas. Due to its usefulness in unsettled or undeveloped areas, it is often used for military and philanthropic applications.
Soil Cement: A Dense Subject
Soil cement is very different from traditional concrete in terms of function and use.  However, the process used to manufacture it is very similar to that used in the production of concrete. Knowing the difference between the two—as well as how each can be applied properly—is integral to effective construction work.
Soil cement is a vibrant example of the versatility and usefulness of cement. It represents emerging technologies and applications of cement as a construction material.  Its use as a stabilizer for raw soil is evidence of cements evolving usefulness.
Most notably, it is an extremely cost-efficient and durable base for roads and other paved areas and should be considered a useful resource during planning and execution of construction projects.

3D Concrete Printing

3D Concrete Printing
The Developing World of 3D printing
Although 3D printing has existed since the 1980s, technological strides and new applications have renewed public interest in the subject. Once an expensive and futuristic technology, 3D printing is becoming a regular part of everyday life and is used in various industries.
3D Printing involves the use of a box-like device to print out layers of liquid material—usually plastic-which hardens to form an object. A computer is connected to the printer and feeds the printer the schematics necessary for the construction of the object. Due to the precise application of liquid “ink” as well as the use of an attached computer, the technology has been compared to traditional digital printers used to print text documents or images.
Though 3D printing technology has become more commonplace in the last few decades, many still associate it with the printing of small plastic objects and knick-knacks. The “box” shape of most 3D printers limits the size of printable objects. Few materials can be liquefied and poured as precisely and effectively as plastic, limiting the versatility of most modern printers.
3D printing has applications beyond the world of basic manufacturing; however, with the development of large printers that can print liquid concrete, large structures such as houses, offices, and even cities could be printed with low cost and relative ease. This new technological frontier could revolutionize the construction industry.
3D Construction: A Recent History
The idea of using 3D printing for construction has existed for almost a decade and has been experimented with around the world. The development of 3D printers for use in construction is motivated by the lucrative idea of building structures quickly and efficiently with significantly decreased manpower.
In 2009, Professor Behrokh Khoshnevis of Southern California created a 3D printer with the capacity to print large concrete structures. In 2014 a Chinese company printed, transported, and assembled ten small houses in less than 24 hours. Despite these strides in 3D printed cement technology, the use of 3D printing for widespread construction remained limited by high prices due to the novelty of the technology and high cost of the machine.
Early 3D cement printers were large, costly machines with limited versatility. They loosely resembled the box-style smaller printers. They consisted of a suspended crane-like appendage inside of a box-like metal frame. This appendage would then move, layering liquid concrete to create structures.
One major weakness of this type of printer is its inability to print structures on-site. Due to their shape, these machines can only produce segments of full structures, which must then be transported to the construction site and assembled.
A newer model of 3D concrete printer, however, accounts for these issues through a revolutionary design. This printer also contains a crane-like appendage, though it is connected to a base, and placed on the ground in the center of the building area. The printer then rotates, constructing the structure around it. When the walls of the structure are complete, the printer is lifted out of the structure so the roof can be manufactured.
This model allows architects and developers to print concrete structures seamlessly on-site.
In 2017, a Russian company used this method of 3D printing to construct a small house in just 24 hours for the relatively low cost of about $10,000. The company constructed the house to demonstrate the efficiency and affordability of the technique. This method of 3D concrete printing shows the potential of the technology to revolutionize the construction industry.
Printing the Future
The potential usefulness of 3D printing in the construction industry is enormous. No region has committed to the technology more than the city of Dubai. In 2016, Dubai enacted a plan to have a quarter of its city consist of 3D printed buildings by 2030. This initiative has driven a remarkable growth in the 3D cement printing industry.
city of Dubai
One company, Cazza Construction Automation, hopes to employ an on-site 3D printer like that used in Russia to revolutionize the construction industry in Dubai.
3D concrete printing technology has enormous potential in developing nations and regions as a cheap, efficient source of reliable housing. A third application of the technology is in disaster areas, where existing housing has been damaged or destroyed. The speed at which structures can be 3D printed could open new doors in disaster management.
A Multi-Dimensional Technology
3D printing has come a long way in its brief history. New technology like 3D concrete printing has the potential to revolutionize the construction industry. It is the dawn of a new era for urban development, efficient public housing, and disaster management.
3D printed structures may soon dot the skyline everywhere, due to incredible efficiency in construction and a price point that is hard to beat.
 

Concrete Flatwork: Pros and Cons

Concrete Flatwork
When it comes to the construction, everyone’s vision is unique in every aspect. The perfect location, the perfect size, and the perfect atmosphere are all going to be different depending on how they mesh with and express your personality, and how they suit your practical needs and requirements of the building.
Where that is most immediately true is in the construction materials you use. This area isn’t necessarily the most exciting question to consider when you’re pondering the perfect place for you to live or work, but it arguably has the most fundamental and significant impact on the building, inside and out – including when it comes to flatwork.
Concrete is an increasingly ubiquitous choice in all sorts of construction flatwork, including basements, pool sides, steps, and gardens.
As a choice for flatwork, concrete has some minor drawbacks. Concrete is a difficult and complex substance to use correctly. You need a quality and experienced firm when you build with concrete.
Here are some of the pros and cons to using concrete in your building’s flatwork.
Pros and Cons to Concrete
Durability
Pros
Maybe the most obvious point in concrete’s favor is that it is extremely – definitionally – durable. Properly maintained, a concrete driveway, for example, can last for 25-50 years. It’s generally a perfect choice for a driveway area, as its high compression strength makes it ideal for supporting extreme loads.
Cons
However, its poor tensile strength means it must be properly supported or reinforced – in areas with bad soil quality, pouring the slab directly onto the ground may lead to problems if it is regularly put under stress. Steel reinforcement and particular mixes and compounds will help to make sure it doesn’t crack as you drive up to your house.
However, reinforcement can’t correct for soil settling, which can become a serious problem. Consult with a specialist about the best way to prepare the earth bed for your concrete surfaces to safeguard against and correct for excessive shifts in the soil.
Versatility
Pros
Concrete is also a particularly versatile substance when it comes to surface finishes. There are a wide array of textures and aesthetic touches available for you to tailor your flatwork to suit your tastes.
As a rule, a brushed finish is recommended for external surfaces, as concrete can become slippery and unsafe to walk on when wet. Interior surfaces are a better choice for a smooth finish, but again, it’s ultimately about what suits you best.
Concrete’s versatility goes beyond the simple choice of smooth or brushed. There are countless different ways for you to tweak the look and feel of your flatwork surfaces to get them exactly how you want them. One popular choice is a stone finish on an external surface, such as a driveway – it’s a straightforward process to apply a pattern to the concrete using a mold while it is still wet, after which point it can be colored according to your preferences.
There are multiple options for coloring your concrete, as well – the traditional choice is an acid-based stain, which provides the most permanent coloring but comes in limited shades. Water-based stain is another popular choice, although it requires a lot more preparation than a solvent-based option, as the concrete’s pores need to be fully open before it is applied. Tinted sealers are also available as a separate option from staining to give your concrete color.
Cons
Concrete that is stained or stamped in this way does require a lot of upkeep to maintain its look. This maintenance includes sealing the concrete every year, to make sure the pattern and the stain don’t fade or get abraded.
When sealing, clean the concrete thoroughly first – any dirt, dust, or stains from other sources must be cleared, or they will prevent the sealer from binding properly to the concrete. This effect goes double for moisture – the concrete must be dry before it’s sealed, especially for the first time, or the sealer won’t adhere correctly.
Conclusion
Concrete is a popular choice for surfaces in and outside your structure for a good reason: it’s extremely tough and long-lasting, versatile in the options it offers for finishing touches and décor, and relatively simple to maintain. While it’s not without its drawbacks, they’re hardly insurmountable.
However, as with any choice about the construction, it’s important to be sure beforehand of exactly what you want – and to know the best way to execute it.
Consult with a specialist before you commit to any one choice and discuss long-term maintenance and repair, so you get surfaces that are guaranteed to last.