Questions tagged [concrete]

For questions about the material concrete, or its application in an engineering context. Concrete is a composite material composed mainly of water, aggregate, and cement.

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(Non)simultaneous prestressing anchorage slip losses

Post-tensioned prestressed concrete beams suffer from a multitude of losses. When jacked, they suffer friction losses and their tension diagram is, for example (to simplify the drawing, I'm using the ...
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0answers
29 views

Waste Foundry Sand as an aggregate for concrete mixes. I have a question regarding grain diameter and it's possible applications

I'm working on a project with a company that uses sand casts during moulding processes and they provided us with samples of the sand they use before it's involved in the procedure and afterwards (...
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0answers
61 views

Any Idea of This China's “Transparent Concrete”?

I am currently make an attempt to make miniaturized version of this China's solar highway on my garage https://www.youtube.com/watch?v=zK8FvzI3yDA Just so i can re-evaluate the performance However, I ...
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0answers
31 views

water leak through subterranean cable penetrations in concrete

See the image below for the detail of 4 no. cable ducts that run from a trench in a raft foundation (on the left) through an approximately 1 m square penetration in the raft foundation, through soil (...
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0answers
233 views

Why do we use the strain-controlled test for the compressive strength of concrete?

As you all now, a typical stress-strain curve for concrete under compression can be seen in any reinforced concrete design textbook. The decreasing part of the curve (post-peak) can be obtained by ...
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23 views

Moisture sensor for Mixers

I'm looking for alternatives to measure the moisture content in a concrete mixer machine. The ones on the market are expensive, like Hidro-Mix for apparent reasons; mixers are a hostile environment ...
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0answers
88 views

Maximum allowable crack in Post Tension concrete

What is the maximum allowable crack size dimension in a post-tension concrete slab before it is considered a "structural" crack, in Arizona, USA? Is there a certain standard for this. I have tried ...
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0answers
45 views

Crooked floor, but ceiling with no incline - could it possibly be a screed?

This question is related to the situation in an apartment in a reinforced concrete building that is approximately 30 years old. The ceiling is almost perfectly straight and level. However, the floor ...
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0answers
7 views

What degree of open span/narrow support can rigid PIR thermal insulating foam sustain under the short term load of setting concrete?

I've found data related to the deformation and shear performance of typical PIR (polyisocyanurate) foams such as Celotex/Kingspan, but I'm not sure how to use these figures in my own situation. I am ...
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0answers
138 views

Bonding steel plate to fiber cement sheet effectively

I've been trying to produce a cheap panel using fiber cement and zincalume sheet. There is a research paper that I read about bonding steel plate to concrete to increase their tensile strength by ...
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26 views

Difference Between minimum steel required in Slabs and Shear Walls

My question is very simple, I need to know why the minimum reinforcement for slabs is less than the minimum reinforcement required in Shear walls? What are the criteria and reasons to set minimum ...
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68 views

How to consider shear forces in CEB/fib 2010 three-layer model for concrete slab design?

I have a question about design of concrete shells with three-layer method described in p.7.3.2.2 fib Model Code for concrete structures. The main idea of method is that we divide shell on three layers....
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308 views

Shift Concrete Column by few inches

While building the foundation of a house, the concrete columns were built 15cm (6 inches) from the planned position, which is reducing the space for a door. The position that should have been there ...
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145 views

Why do we dig holes and fill them in with concrete?

I'm watching construction of a new building across from my office. The old building has been demolished and the demo team has completed taking everything away and a new company has come in to start ...
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0answers
23 views

How to calculate load bearing capacity of a floating pavement?

Given tire load of a vehicle, how do I calculate load bearing capacity of a non-reinforced concrete pavement floating on a layer of heat insulation material, which is on the RC base? I can't figure ...
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28 views

Modern equivalent concrete strength to 'Class Ws 3/4" '

Consider the following extract from a UK reinforced concrete detail drawing dated 1970: What is the modern equivalent to this concrete class?
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1answer
69 views

installing swing hook before concrete is poured

I want to place a swing hooks in place before the concrete is poured so that , i dont have to drill a hole later. My contractor is not ready to make these bolts with TMT bars itself.. what kind of ...
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34 views

House construction using concrete panels

Background Information Currently looking to buy a house in the Southampton area in the UK and have noted there are quite a few houses which use a concrete panelling construction technique see example ...
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2answers
102 views

Reinforced mesh at different distance in a concrete slab?

Trying to determine some information regarding the reinforced concrete slabs (reinforced with mesh) in an apartment, by looking through the holes in the middle of the rooms for lights, I've come ...
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22 views

How to build multiple large scale fish tanks with water at different temperatures

I am wondering at a high level what are the material components that might be used in building several large scale fish tanks that are temperature regulated like on a fishing farm. For example, what ...
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49 views

How to grind into concrete ( not core drill )

I have a very specific and weird task I need to accomplish. I have a concrete wall that I need to get samples of the concrete dust to grind and get them tested, i plan on using a plunge router with a ...
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42 views

Will screed on plywood do instead of beam and block, to replace a floor?

I'm gutting and redoing an older house (early 20th C, ordinary suburban terrace house, London UK). I'd planned beam and (dense) block for the upstairs structural floor, for a few reasons, and already ...
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1answer
42 views

How does Gypsum Concrete work?

When mixed with water how does gypsum act as a binder in creating concrete?
-1
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1answer
41 views

Is there a standard formula available to calculate lateral concrete pressure from the measurements of lateral concrete strain?

As shown in the image, I have done a vibrating wire type strain gauge and pressure cell (not shown in the image) instrumentation on full scale form. the objective is to measure the lateral pressure of ...