What is Concrete: Definition and 147 Discussions

Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. In the past, lime based cement binders, such as lime putty, were often used but sometimes with other hydraulic cements, such as a calcium aluminate cement or with Portland cement to form Portland cement concrete (named for its visual resemblance to Portland stone). Many other non-cementitious types of concrete exist with other methods of binding aggregate together, including asphalt concrete with a bitumen binder, which is frequently used for road surfaces, and polymer concretes that use polymers as a binder. Concrete is distinct from mortar. Whereas concrete is itself a building material, mortar is a bonding agent that typically holds bricks, tiles and other masonry units together.When aggregate is mixed with dry Portland cement and water, the mixture forms a fluid slurry that is easily poured and molded into shape. The cement reacts with the water and other ingredients to form a hard matrix that binds the materials together into a durable stone-like material that has many uses. Often, additives (such as pozzolans or superplasticizers) are included in the mixture to improve the physical properties of the wet mix or the finished material. Most concrete is poured with reinforcing materials (such as rebar) embedded to provide tensile strength, yielding reinforced concrete.
Concrete is one of the most frequently used building materials. Its usage worldwide, ton for ton, is twice that of steel, wood, plastics, and aluminum combined. Globally, the ready-mix concrete industry, the largest segment of the concrete market, is projected to exceed $600 billion in revenue by 2025. This widespread use results in a number of environmental impacts. Most notably, the production process for cement produces large volumes of greenhouse gas emissions, leading to net 8% of global emissions. Significant research and development is being done to try to reduce the emissions or make concrete a source of carbon sequestration. Other environmental concerns include widespread illegal sand mining, impacts on the surrounding environment such as increased surface runoff or urban heat island effect, and potential public health implications from toxic ingredients. Concrete is also used to mitigate the pollution of other industries, capturing wastes such as coal fly ash or bauxite tailings and residue.

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  1. J

    Wavelength / signal which would pass through concrete and rubble

    Greetings, Please imagine a huge pile of rubble, meters deep. Somewhere inside, there's a device emitting a certain signal. This signal can be picked up by a radar-like device which locates the origin of that signal, with the least interference from the pile of rubble, concrete blocks, metals...
  2. C

    Residential concrete densifier and sealer?

    Hello! I have absolutely no background in the sciences / chemistry, so I thought maybe you folks could help dumb it down for me. I am renovating an old house and just got new concrete poured in the basement. I want to polish the floors and leave them uncovered for environmental and health...
  3. K

    Measuring Pressure on a Concrete Table

    Hi guys, I am not doing homework, it is just suddenly brainstormed this question. What if I place a very small mass like 10kg on the center of a concrete 10m*10m flat table supported by the ground, then how to measure the surface pressure acting on the center and right on the edge? Or the...
  4. P

    B How do I express the force of me falling 33 feet onto concrete?

    I weight 90.7kg. I fell 10.05m landing on soild concrete. how do I express the "power of my impact? in G-force? A relitive weight? I am self taught in very basic physics after a high school education.
  5. BohmianRealist

    A Bootstrapping quantum Yang-Mills with concrete axioms

    From: https://en.wikipedia.org/wiki/Axiomatic_quantum_field_theory But, that seems like a fairly abstract place to begin the kind of QFT construction that was asked of us by Witten in 2012: At the bottom of that page on axiomatic QFT are the "Euclidean CFT axioms": Are there any examples of...
  6. S

    Strange pattern on a concrete paved surface

    I found this funny pattern in a slightly damp concrete paved parking area. Any ideas what it is?Detail :
  7. okandrea

    Structural Systems: Steel and Reinforced Concrete (RC)

    I've been looking over precedents for a design project and I noticed that the most commonly used systems are either steel or reinforced concrete structural systems. Is it possible for a steel structural system to be connected to a reinforced concrete structural system? If so, how does it work...
  8. P

    Can I Transform Multiple Steel Beams into a Single Piece of Concrete?

    When I convert the steel beams to concrete, do I transform the several different beams into a single piece of concrete in order to do the calculations to find the second moment of area of the beam or do I transform each beam seperately into a concrete piece? Intuitively, t seems reasonable to...
  9. A

    Medical Has CRISPR-Cas9 found a concrete application?

    If so which? If not when is it expected to do so? By concrete application I mean as being employed for curing diseases, or for some other practical purpose that goes beyond the foundational research.
  10. L

    How to pick a concrete PhD objective in this QFT/Gravity formalism?

    I have a major in Mathematics and Mathematical Physics and I'm finishing a masters in Physics (just finishing to write down the dissertation really). I have also already enrolled the PhD course so that I need now to pick an advisor and a theme before june. My main interest since the early days...
  11. V

    Calculate lateral force/pressure of a body water

    So I'm planning to build an above ground concrete fish pond. The size of the inside of the pond will be (L)2000mm x (W)500mm x (D)500mm. What I want to know before I go any further is will the poured concrete walls hold the pressure of the water inside. So if I know the pressure of water I'll...
  12. R

    I Understanding metric space definition through concrete examples

    Right now, I am studying Advanced Calculus (proof based), and it is hard thinking through some of the definitions without first thinking about it concretely (meaning how to visualize it better geometrically, if that makes any sense?). I need help with this definition. Definition Let X be a...
  13. J

    Is it possible to pour concrete in a vacuum?

    One idea for a moon base would be reinforced concrete domes, but is pouring concrete in a total vacuum even possible? Wouldn't the water just evaporate, or is there another material we could use instead of water? Are the ingredients of concrete plentiful on the moon, or could we synthesize them...
  14. F

    Prestressed concrete - tension in steel cables

    Hello Everyone, I was learning about prestressed concrete and how it works. Concrete is very strong under compression but weak under tension. In the case of prestressed concrete, the steel bars are pulled and become elongated. How much do the steel bars elongate when they are pulled? The...
  15. N

    What is the ideal thickness for a concrete slab for a chemical storage tank?

    Good morning forum, I'm currently in the middle of a project where I'm installing a new chemical storage tank outside. I need to lay a new concrete slab for the tank to lay on. My question is how thick should the concrete slab be? The tank will be stationary, when filled it will weigh...
  16. C

    I Stress exerted on a wooden cube dropped on concrete floor

    I wonder if it is possible to at least estimate the stress (or the impact force) that the cube in question will experience due to the collision with the concrete floor. Assumptions: 1. The cube is dropped from height h 2. The cube is relatively small, thus we can neglect air resistance...
  17. C

    Car acceleration on concrete and on asphalt

    Today I've come across the statement that the coefficient of static friction of rubber tires on asphalt is bigger than that of tires on concrete. Does it mean that the maximal acceleration a car can attain on asphalt will be greater than that on concrete? My assumptions: 1)The force of friction...
  18. A

    Rienforced Concrete Column Cost Optimization with Genetic Algorithm

    Hi, I'm a Civil Engineering student doing my final project for my BE degree. I have developed a software that uses a genetic algorithm for optimizing reinforced concrete columns. I have tested my program with a 17 stories building, and got some very unusual results in the design but much...
  19. anon3005

    Friction of rubber box on concrete floor

    Homework Statement A 10 kg rubber box is resting on a concrete floor. A force of 200 N is then applied to this box in a horizontal direction. What is the magnitude of the friction force on the box? Homework Equations This is a question about applying Newton's laws so Fsmax = μs η and η = mg...
  20. P

    Materials engineering Concrete

    Homework Statement How does the compressive strength of concrete samples compared to the expected compressive strength of cured concrete. If different explain why. The Attempt at a Solution I think the question is asking what is the relationship between time and curing. And I think that the...
  21. F

    What is the Correct Calculation for Stress in Steel and Concrete?

    Homework Statement here's the question , Part of solution was given , but not the final ans . I have tried to do , but i need someone to verify my ans . Homework EquationsThe Attempt at a Solution Since , stress of steel is 12.5 times of stress of concrete . The max allowable stress in steel...
  22. O

    I Concrete contrast between local and nonlocal hidden variable

    Can someone concretize the difference between a "hypothetical reality" where hidden variables are local and hidden variables are nonlocal in the following context: Some physical event occurs involving particles A and B (which are/become entangled and will exhibit correlations) at time T and...
  23. Q

    Max height of a concrete column

    Homework Statement For a concrete column of constant cross sectional area, what is the maximum possible height if the compressible strength is 2.0 x 107 N/m2? The density of concrete is 2.3 x 103 kg/m3. Homework Equations \frac{F}{A} The Attempt at a Solution I am not really sure what I am...
  24. Reno Nza

    Repairing concrete structures using composites

    I've been searching for a while, but all the knowledge related to this field seems to be developed on field, so, does people here has any data related to such kind of repair ? I'm mechanical engineer whiling to relocate my field of actuation to this area, repair and reinforcement of structures...
  25. R

    Cracking Concrete from Freezing Water in Corrugated Pipe

    I am a structural engineer and have a situation where we have a corrugated plastic pipe formed inside of a square concrete column (pipe is 4" in diameter and column is 16x16). The top of the corrugated pipe is flush with the top of the concrete and open to the atmosphere. The bottom of the...
  26. N

    Concrete Block Incline acceleration question

    Homework Statement A concrete block of mass 25kg is placed on a smooth slope that makes an angle of 30 degrees with the horizontal. Ignoring the effects of air resistance, calculate a) the acceleration of the block as it slides down (g = 9.81 ms-2) b) the distance the block moves in 3 seconds...
  27. C

    [Traffic Flow] Concrete example of conservation equation?

    This is it; most likely the last time I bother the people of this website with my questions on traffic flow. I'm trying to figure out some concrete examples to demonstrate utilization of the conservation equation in traffic flow: \frac{\partial \rho }{\partial t} + \frac{\partial q(\rho...
  28. S

    Using ferromagnetism in reinforced concrete

    Hey there, I am currently majoring in civil engineering. A while ago when I was wondering about ferromagnetism an idea occurred to me: In reinforced concrete design adherence between structural steel and concrete is a very important feature. Simply, if we could enhance the adherence, this...
  29. A

    How Thick Should the Concrete Foundation Be to Counteract Buoyancy Underwater?

    Hello, I have a question about buoyancy of concrete in water. If a submersible pump station is placed under water, and it has under it a concrete foundation to hold it in equilibrium. How can someone calculate the minimum weight of the concrete foundation? The pump station has a diameter: 1.6...
  30. O

    Calculating Forces in a Concrete Slab Supported by a Chain

    Homework Statement A 500-kg concrete slab is supported by a chain and sling attached to the bucket of the front-end loader shown. The action of the bucket is controlled by two identical mechanisms, only one of which is shown. Knowing that the mechanism shown supports half of the 500-kg slab...
  31. ichabodgrant

    Size of specimen and compressive strength of concrete

    Hello everyone. I have a question about compressive strength of concrete. It is said that (in my country) 150 mm x 150 mm x 150 mm concrete cube is used for concrete testing. Someone asks me why 100 mm x 100 mm x 100 mm is not used. In fact, I know that sometimes it is allowed or even preferred...
  32. M

    The final answer to the car battery on a concrete floor (ruins the floor)

    People keep asking about setting a car battery on a concrete floor somehow ruining the battery. Here is the final answer on the subject. I have the 1930s Popular Science with the original tip in it (but don't ask me which issue). The auto tip was: "Leaving a car battery on a concrete floor...
  33. sanderr2

    Simplistic fluid heat loss - water in a concrete tank

    Hi all, I'm sorry if this is an inappropriate question. I have built a basement swimming pool for my wife. Unfortunately I neglected to insulate outside the concrete and insulating inside the concrete has caused some construction issues so I am trying to work out the heat loss if I go ahead...
  34. J

    120v DC concrete drillmotor project, good power source?

    Hello every one umm... I am very new at all of this and I need your help. I have a project that I am working on and it involves a 120V 4.5amp DC concrete drill motor and my bike. I am using this motor because it has enough torque and I just got kinda bored lol anyway, I am having a bit of...
  35. B

    Why isn't concrete used more in the construction of high rise buildings?

    If you had a pipe with a ID of 125 mil and was over 500 meters long filled with 5m3 of concrete what would the pressure be at the bottom
  36. P

    Concrete Columns: Building a 3-Floor House

    This is regarding a building a house with 3 floors. I have seen some masons are first do the concrete structure and then they do the brick structure. But I have seen some do the basement first and do the bricks first and in between they keep a space for columns and they pour concrete mixture in...
  37. H

    Definition of tensors - abstract and concrete

    I am well aware of an abstract definition of a general tensor as a map: \mathbf{T}:\overbrace{V\times\cdots\times V}^{n}\times\underbrace{V^{\star}\times \cdots\times V^{\star}}_{m}\longrightarrow\mathbb{R} I am happy with this definition, it makes a lot of sense to me. However, the physics...
  38. A

    Shoulders on railway tracks concrete sleepers

    Hi, I want to ask the shoulders that are used on railway tracks concrete sleepers, should they be forged or ductile cast and why? If someone can post an article it'll be great. Thank You for your help and support.
  39. M

    Concrete and pressure no air nothing more than gravity

    So I'm looking for how tall I could make a tower of concrete, using any reinforcments, in an environment of only gravity starting at sea level. Could it get so tall it'll own gravity would effect it, the moons, or the sun's gravity, or would the bottom give out will before that?
  40. S

    Predicting the Density of Concrete

    Hello Everyone, I have a problem which is flummoxing me concerning concrete! The density of concrete is approx. 2400 kg/m^3 (depending on mix) however the component parts which make up concrete are as follows: Water (density 998 kg/m^3) Cement (density 1506 kg/m^3) Aggregate...
  41. T

    Dimension change of opening through concrete slab expansion

    Hi, apologies for the length of this, I'm hoping as a group you knowledgeable established or future Engineers and Physicists can help me out with a problem. I have been having a discussion with a colleague about expansion of a 6m x 7m integrally waterproofed (Kryton KIM) concrete slab roof that...
  42. D

    Tension on bolts in anchor plate on concrete wall

    Hi. I need help calculated the tension on bolts in an anchor plate. The plate is bolted to a concrete wall with four bolts (see the included image). A bending moment acts on the plate, offset a bit up/down. The bending moment acts from up to down so that the upper two bolts are in tension and...
  43. P

    Max Drum Rotate Speed of a Concrete Mixer Drum

    Homework Statement In a concrete mixer, cement, gravel, and water are mixed by tumbling action in a slowly rotating drum. If the drum spins too fast the ingredients stick to the drum wall instead of mixing. Assume that the drum of a mixer has radius ##R = 0.5 m## and that it is mounted with...
  44. D

    How long must concrete slab cure before anchoring equipment?

    We cut the concrete flooring in our plant for some plumbing work and will soon re-pour a slab of 5,000 PSI "High-early" concrete. In order to minimize down-time we need to re-install equipment by drilling/anchoring into new concrete as soon as the curing has yielded sufficient strength. The...
  45. Dennydont

    What is the maximum load the concrete can support?

    Homework Statement A certain type of concrete has a tensile breaking stress of 3.1 MN/m^2, a compressive breaking stress of 37.7 MN/m^2 and a shear breaking stress of 9.4 MN/m^2. A circular pillar of this concrete has a radius of 0.6 m. What is the maximum load it can support assuming that it...
  46. R

    How to find thickness of steel plate

    I have a 300 mm diameter hole in the ground surrounded by concrete. This hole will be covered by a steel plate. I need to get a machine of weight 2.5 tonnes across this hole safely without any bending of the steel plate. How would i calculate the required thickness of the plate? Thank you Ron.
  47. M

    Structural analysis of a concrete frame

    Hello. I have a project for next semester and I'm thinking of creating a program using mathematica to analyze a concrete frame to obtain the moment and shear diagram. What would you consider the best method for analysis. The loads will be uniformly distributed. Any tip will be greatly...
  48. H

    12m span of concrete roof slab

    Hi, I am designing a concrete roof slab that span across 12m long and 9m width for my living area. The support columns are placed in each 4 corners and they are 300mm x 300mm size. The concrete slab roof is cantilevered out by 1.8m on 3 sides (not all 4 sides) with the thickness of 150mm. At the...
  49. L

    How to build something to vacuum and convey concrete powder

    Need to move some concrete powder, would like to use compressed air or a blower. I will need it to vacuum and convey the product, the storage vessel is broken and there is no way to gravity or manually feed it. The vertical distance is 8-10' and no more then 20' horizontal. I have played around...
  50. T

    A worker lifts a 20.0-kg bucket of concrete from the ground

    Homework Statement A worker lifts a 20.0-kg bucket of concrete from the ground up to the top of a 20.0-m-tall building. The bucket is initially at rest, but is traveling at 4.0 m/s when it reaches the top of the building. What is the minimum amount of work that the worker did in lifting the...