Concrete is reinforced to give it extra tensile strength; without reinforcement, many concrete buildings would not have been possible.

Reinforced concrete can encompass many types of structures and components, including slabs, walls, beams, columns, foundations, frames and more.

Reinforced concrete can be classified as precast concrete and cast in-situ concrete.

Much of the focus on reinforcing concrete is placed on floor systems. Designing and implementing the most efficient floor system is key to creating optimal building structures. Small changes in the design of a floor system can have significant impact on material costs, construction schedule, ultimate strength, operating costs, occupancy levels and end use of a building.

Source: Wikipedia

The difference in nomenclature between stucco, plaster, and mortar is based more on use than composition. Until the later part of the nineteenth century, it was common that plaster, which was used inside a building, and stucco, which was used outside, would consist of the same primary materials: lime and sand (which are also used in mortar). Animal or plant fibers were often added for additional strength. In the later part of the nineteenth century, Portland cement was added with increasing frequency in an attempt to improve its durability. At the same time, traditional lime plasters were being replaced by gypsum plaster.

Traditional stucco is made of lime, sand, and water. Modern stucco is made of Portland cement, sand, and water. Lime is added to decrease the permeability and increase the workability of modern stucco. Sometimes additives such as acrylics and glass fibers are added to improve the structural properties of the plaster. This is usually done with what is considered a one-coat stucco system, as opposed to the traditional three-coat method.

Source: Wikipedia

Concrete solidifies and hardens after mixing with water and placement due to a chemical process known as hydration. The water reacts with the cement, which bonds the other components together, eventually creating a stone-like material. Concrete is used to make pavements, architectural structures, foundations, motorways/roads, bridges/overpasses, parking structures, brick/block walls and footings for gates, fences and poles.

Concrete is used more than any other man-made material in the world. As of 2006, about 7.5 cubic kilometers of concrete are made each year, more than one cubic meter for every person on Earth. Concrete powers a US $35-billion industry which employs more than two million workers in the United States alone. More than 55,000 miles (89,000 km) of highways in the United States are paved with this material. The People’s Republic of China currently consumes 40% of the world’s cement/concrete production.

Reinforced concrete and Prestressed concrete are the most widely used modern kinds of concrete functional extensions.
Contents.

Source: Wikipedia

Prestressing can be accomplished in three ways: pre-tensioned concrete, and bonded or unbonded post-tensioned concrete.

Prestressed concrete is the predominating material for floors in high-rise buildings and concrete chambers in nuclear reactors.

Unbonded post-tensioning tendons are commonly used in parking garages as barrier cable. Also, due to its ability to be stressed and then de-stressed, it can be used to temporarily repair a damaged building by holding up a damaged wall or floor until permanent repairs can be made.

The advantages of prestressed concrete include crack control and lower construction costs; thinner slabs – especially important in high rise buildings in which floor thickness savings can translate into additional floors for the same (or lower) cost and fewer joints, since the distance that can be spanned by post-tensioned slabs exceeds that of reinforced constructions with the same thickness. Increasing span lengths increases the usable unencumbered floorspace in buildings; diminishing the number of joints leads to lower maintenance costs over the design life of a building, since joints are the major locus of weakness in concrete buildings.

Source: Wikipedia

Incoming search terms:

• Prestressed concrete
• prestressed concrete buildings

The terms asphalt concrete, bituminous asphalt concrete, etc., are typically used only in engineering jargon. Asphalt pavements are often called just asphalt by laypersons who tend to associate the term concrete with Portland cement concrete only. The engineering definition of concrete is any composite material composed of mineral aggregate glued together with a binder, whether that binder is Portland cement, asphalt or even epoxy. Informally, asphalt concrete is also referred to as blacktop.

Asphalt concrete is often touted as being 100% recyclable. Several in-place recycling techniques have been developed to rejuvenate oxidized binders and remove cracking, although the recycled material is generally not very water-tight or smooth and should be overlaid with a new layer of asphalt concrete. Asphalt concrete that is removed from a pavement is usually stockpiled for later use as a base course material.

Asphalt concrete has different performance characteristics in terms of surface durability, tire wear, braking efficiency and roadway noise. The appropriate asphalt performance characteristic is obtained by the traffic level amount in categories A,B,C,D,E, and friction coarse (FC-5).

Asphalt concrete generates less roadway noise than Portland cement concrete surfacing, and is typically less noisy than chip seal surfaces. Tire noise effects are amplified at higher operating speeds. The sound energy is generated through rolling friction converting kinetic energy to sound waves. The idea that highway design could be influenced by acoustical engineering considerations including selection of surface paving types arose in the very early 1970s.

Source: Wikipedia

It has since been refined into a high thermally insulating concrete-based material used for construction both internally and externally. Besides insulating capability, one of AAC’s advantages in construction is its quick and easy installation since the material can be routed, sanded and cut to size on site using standard carbon steel band saws, hand saws and drills.

Even though regular cement mortar can be used, 98% of the buildings erected with AAC materials uses thin bed mortar, which comes to deployment in a thickness of 1/8 inch. This varies on national building codes and creates solid and compact building members. AAC material can be coated with a stucco compound or plaster against the elements. Siding materials such as brick or vinyl siding can also be used to cover the outside of AAC materials.

Produced for more than 70 years, AAC offers considerable advantages over other construction materials, one of the most important being its very low environmental impact.

Source: Wikipedia

Source: Wikipedia

Fibers are usually used in concrete to control plastic shrinkage cracking and drying shrinkage cracking. They also lower the permeability of concrete and thus reduce bleeding of water. Some types of fibers produce greater impact, abrasion and shatter resistance in concrete. Generally fibers do not increase the flexural strength of concrete, so it can not replace moment resisting or structural steel reinforcement. Some fibers reduce the strength of concrete.

The newly developed FRC named Engineered Cementitious Composite (ECC) is 500 times more resistant to cracking and 40 percent lighter than traditional concrete. ECC can sustain strain-hardening up to several percent strain, resulting in a material ductility of at least two orders of magnitude higher when compared to normal concrete or standard fiber reinforced concrete. ECC also has unique cracking behavior. When loaded to beyond the elastic range, ECC maintains crack width to below 100 µm, even when deformed to several percent tensile strains.

Source: Wikipedia

The production of lunar cement would be an energy-expensive process, estimated to require 2,200 kW h per megatonne. Thus there would need to be significant infrastructure in place before industrial scale production of lunarcrete could be possible.

The casting of lunarcrete would require a pressurized environment, because attempting to cast in a vacuum would simply result in the water, required for the chemical reaction that forms the curing process, evaporating, and the lunarcrete failing to harden. Two solutions to this problem have been proposed: premixing the aggregate and the cement and then using a steam injection process to add the water, or the use of a pressurized concrete fabrication plant that produces pre-cast concrete blocks.

Lunarcrete shares the same lack of tensile strength as Terrestrial concrete. One suggested Lunar equivalent tensioning material for creating pre-stressed concrete is lunar glass, also formed from regolith, much as fiberglass is already sometimes used as a Terrestrial concrete reinforcement material. Another tensioning material, suggested by David Bennett, is Kevlar, imported from Earth (which would be cheaper, in terms of mass, to import from Earth than conventional steel).

The basic ingredients for lunarcrete would be the same as those for Terrestrial concrete: aggregate, water, and cement. In the case of lunarcrete, the aggregate would be lunar regolith. The cement would be manufactured by beneficiating lunar rock that had a high calcium content. Water would either be supplied from off the moon, or by combining oxygen with hydrogen produced from lunar soil.

Source: Wikipedia

Incoming search terms:

• lunarcrete

By producing precast concrete in a controlled environment (typically referred to as a precast plant), the precast concrete is afforded the opportunity to properly cure and be closely monitored by plant employees. Many states across the United States require a precast plant to be certified (either by APA, NPCA or PCI) for a precast producer to supply their product to a construction site sponsored by State and Federal DOTs. There are many different types of precast concrete forming systems for architectural applications, differing in size, function and cost.

Ancient Roman builders made use of concrete and soon poured the material into molds to build their complex network of aqueducts, culverts and tunnels. Modern uses for precast technology include a variety of architectural and structural applications featuring parts of or an entire building system. Precast architectural panels are also used to clad all or part of a building facade free-standing walls used for landscaping, soundproofing and security walls. Stormwater drainage, water and sewage pipes and tunnels make use of precast concrete units. The advantages of using precast concrete is the increased quality of the material, when formed in controlled conditions, and the reduced cost of constructing large forms used with concrete poured on site. The New South Wales Government Railways made extensive use of precast concrete construction for its stations and similar buildings. Between 1917 and 1932, they erected 145 such buildings.

Source: Wikipedia