Concrete - Science topic

Can 3D concrete printing technology at the current level of development be considered sufficiently developed to be widely used? What are the examples of the largest structures made in 3D concrete printing technology? Are there examples of residential buildings in real use, not just demo buildings?

The reason for asking is that the method described in the former article is not valid on the basis of the experimental evidence provided in the latter.

Design concrete shear wall in SAP23

Can you use both resin and asphalt in a concrete mix?

Hi

thanks for help me

How to import Kent-Scott's concrete model in Abaqus with CDP method.

It was not possible to enter the concrete specifications for the Kent-Scott model without tensile strength.

The software does not allow defining the concrete model without tensile strength.

What lightweight waste aggregates are used for concrete in your country?

Can cement and liquid sulfur be used in a concrete mix at the same time?

Do you know a book on scanning electron microscopy of concrete/cement?

Can asphalt and liquid sulfur be used in a concrete mix at the same time?

Can cement and asphalt be used in a concrete mix at the same time?

Can organic or natural ingredients be used in concrete mixes?

What concrete binder is used in your country? (cement, ash, slag ... and what else?)

In fact, I notioced that some of the students' styles, organization, and ideas in paragraph and essay writing, especially the activities they do at home, started to develop in a concrete way. Does it really have to do with the use of the new AI tool? or is it just a coincidence?

Thanks for your comments

Mustapha Boughoulid

Hello Everyone,

I am trying to do a stability analysis of a gravity dam using sap2000. what is the best way to model the soil structure interaction using this software (The soil is rigid rock)? also, is there a possibility to model the concrete joints in sap2000?

Thank you

What is permissible value of depth of water penetration in normal concrete. How much this value could be reduce in Ultrafine concrete.

What is permissible value of chloride ion penetrability in normal concrete in coulombs and how much this value could be reduce in Ultrafine concrete.

In SAP2000, in material properties mander stress-strain curves are added by default for unconfined and confined conditions. How much default tensile strength of concrete is considered in SAP2000 as per Mander's curves?

seismic loads ,earthquakes and earthquakes dampers

what is the coefficient of friction between the surfaces of a precast concrete with a cast in situ concrete for use in Abaqus ?

This is for modelling a sandwiched slab consisting of three layers of concrete

1. The elastic column has the ability to move elastically in the earthquake as it also has the necessary plasticity for inelastic displacements. On the other hand, it does not put down large torques at the base However, the column does not have dynamics like a rigid reinforced wall, and it does not have a second lever arm in width, which reduces the overturning moment. The wall has great dynamics towards the earthquake, it has a second lever arm in width that reduces the overturning moment, but it does not have great plasticity and on the other hand, it lowers large moments to the base due to stiffness and breaks beams and joists. Also, due to greater mass, the inertia of the structure increases and thus the seismic loads. Question Is there a vertical load-bearing element that has a double lever arm, ductility, elasticity, dynamics, and does not transmit its moment to the beams and joists, and is strong towards the intersection of the base, and economical with the minimum steel reinforcement? Yes there is. But they don't use it It is called an elongated wall with prestressed and ground-consolidated ends.

2. If we want to increase the response of the structure to the earthquake, we increase the mass of the concrete by building walls and large beams. We are still increasing the steel reinforcement. Nicely we built a dynamic rigid structure something like a reinforced concrete precast which has great dynamics. Normally it should withstand the earthquake. However, it does not last, especially when the construction is tall. The reasons are as follows. By increasing the mass, we also increase the inertia of the structure and thus the seismic loads. By increasing the height and stiffness we increase the overturning moment These three factors, if they do not overturn the structure, will at least create a small overturning - swelling in the area of the base of the building. The structure losing partial soil support will divert the now unsupported static loads to the beam cross-sections and break them. This happens when we increase the dimensions of the load-bearing organism to increase the dynamic response of the structure. Question There is a solution? Yes, there is a solution. We must increase the dynamics of the structure without increasing its mass, which causes greater inertia. That is, we can increase the linear and transverse reinforcement, and the quality of the concrete, as well as reduce the diameter (not the kilograms) of the reinforcement, in order to achieve greater resistance, in terms of the shear failure of the coating concrete, due to its super strength steel in tension. This they do today and have greatly improved the dynamics and ductility, but greatly increased the cost of steel reinforcement. A steel of diameter Φ/50 has the ability to lift a two-story building with an area of 100 m2 weighing 140 tons, and today they put 8500 kg of steel on the two-story and we have failures in large earthquakes. And this is because the concrete cannot hold the steel reinforcement in it to cooperate and it breaks. Is there another solution? Yes, there is another solution and it is the one I propose. This solution removes 80% of the reinforcement so the construction becomes more economical. This solution triples the dynamic response of the structure to seismic displacements, without increasing the mass, i.e. the inertia that causes the seismic loads, and this happens because the force that counteracts the earthquake comes from an external factor, that of the ground, so it has no mass added to the structure. This solution diverts the seismic loads outside the structure and the structure is not stressed by the earthquake. This solution is called an elongated wall with prestressed and soil-consolidated ends.

In this research, I am trying to replace the traditional bricks and concrete because these materials have much weight causes increasing the weight of the overall structure.

want some information regarding the use of concrete grade greater than M60 in different building projects.

Hello,

I think that the question is pretty straightforward. Are you able to evaluate fracture toughness of concrete without COD measuring device? I've already red that it should be possible, but was it ever used?

Thanks.

In brief with neat sketch

I was looking over the internet and could not find a satisfactory answer: What is a "concrete" (i.e., in applications outside of Math.) solution of any (definite) stochastic integral or rather how to find such a solution ? Recall that in the stochastic integration the result (which we can eventually apply) of the integration is not a number nor another stochastic process but a random variable. So, how to get it and also how to find or approximate its probability distribution ?. Shall we integrate ALL the realizations of the integrated process or some of them to obtain a statistical sample of the solution or somewhat else. Where can I find this problem properly elaborated or who can

explain this ? Jerzy F.

Why Johnson-Holmsquist-2 model is not taken as concrete property in Abaqus/CAE, for dam? Or what are the limitations or advantage of taking JH-2 model as concrete in ABAQUS.

Each material is more resistant to a certain force. Concrete and above all prestressed concrete withstands compressive stress. In tensile bending torsion and shear it has a problem. Reinforcing steel has super tensile strength. And we make these two materials work together so that the concrete receives the compression and the steel receives the tension. Great combination. Is it so or not? No, its not like that. Ideally, the steel and concrete would have exhausted their compressive and tensile strengths before they failed. But this does not happen. Both concrete and steel fail before they exhaust their strength. This is because during the bending of the body of the load-bearing elements, in addition to the compressive and tensile forces, another force, the shear force, appears on the interface where the concrete and steel are in contact. The concrete covering the steel having no resistance to the shear force breaks along the steel and their cooperation stops. Thus before the steel and concrete exhaust their tensile and compressive strengths, shearing cancels their strengths. This problem grows even more when the critical area of failure occurs at the ends of the load-bearing elements, because apart from the mentioned problem we also have the potential difference in adhesion. Another problem is that the cover concrete does not withstand bending and breaks leaving the steel reinforcement exposed so the bond is cancelled. The ideal would be if we could eliminate the bending of the beam and the shearing that occurs at the concrete-steel interface when the steel begins to stretch. Then only concrete and steel would exhaust 100% of their ultimate compressive and tensile strengths before failing. There is a solution? Yes there is a solution but it is rarely used. It's called, prestressing. Prestressing uses the steel to compress the concrete with the help of hydraulic pullers, and compaction systems at their ends. The compression in the concrete makes it capable of receiving the developing tensile forces. It reduces the bending of the trunk, thus also the deformation of the load-bearing element. It increases the effective cross-section because the compressive force is distributed throughout the cross-section, effectively eliminating the inert concrete cover. The main one is that prestressing has strong ductility and is considered elastic since it restores the structure (compression ratio) to its original position by tilting the developing cracks after a strong inelastic displacement of the structure. Now why they don't do this to the walls that are the cause of the distortion in the whole structure I don't know. If prestressing is applied at the ends of the longitudinal rigid walls and is combined with compaction in the foundation soil then the overturning moment and the bending moment and the shear failure of the cover concrete will be stopped and the response of the cross section will increase with respect to the other intersecting that of basis. Consider that a Φ/50mm cross-section steel lifts a two-story building into the air and we place 8000 kg of steel on the two-story building and have an earthquake problem due to shear failure.

28 days cured alkali activated binder samples were immersed in acetone to stop the hydration reaction before characterization. The samples immersed in acetone were stored in oven in a controlled temperature of 22 +/- 2 degree Celsius. That oven has a temperature range of up to 80 degree Celsius.

While my samples were stored , the oven malfunctioned and the temperature raised to its maximum limit (80 degree Celsius). When I went to store few more sample, I saw the temperature was fluctuating between 75 and 80 degree Celsius and the acetone in vails was boiling (as it has low boiling point).

With the acetone wash, the hydration reaction of samples was stopped but I am wondering if the samples stored in that acetone are still suitable for characterization? or I should synthesize the samples again. Kindly comment your opinion.

Concrete as used in the Pantheon is self healing. Using siiica fume, or metakaolin with lime based cementitious materials as used by the Romans could be of great interest. If only we could add domething to speed ip strength gain.

I am trying to simulate the sliding displacement of a block of concrete (subjected to a concentrated force of 5000N in the Z direction from the reference point) situated on the CFRP. I put an encastrement on the bottom plate of CFRP and a displacement (U2=0) under the concrete.

As I saw on tutorials, I created an Interaction Property (Contact > Friction > Tangential > Penalty and Friction=0.17 ; Normal > Hard) and then I created the Interaction. I have tried both General (Standard) and Surface to Surface (Standard) but none works. Moreover, I have tried with a solid part and a shell part for the CFRP... Also, I have tried with a Static, General Step (with Nlgeom ON) and a Linear perturbation Step. However, I never succeed to see any displacement of my block of concrete ...

Thank you for any help.

In brief with neat sketch

I am trying to add a section on the environmental impact of concrete ingredients in my manuscript. Could someone help me find the eCO2 value of ultrafine slag?

the maximum value in the (yield stress) column in CDP definition should be :

fck,

fck,cube

or

fcm ??

I am starting to work on a project concerning DEF or SEF as a damage mechanism. We are not able to find any standard accelerated tests for DEF. I have read about Duggan, Fu, and Kelham methods etc. They seem to be quite old. Are there any standard accelerated tests that have been developed for this?

I will like to know Na2O limit in geopolymers to be used as binders in concrete application. Could there be a risk of ASR?

Hi,

I am trying to simulate the flow of fresh concrete using the CEL technique in Abaqus. But when the analysis reaches a certain time (256 sec), the job gets stuck at this time. Does anyone know why?

I am working on a RC column on Abaqus that uses concrete damage plasticity of Mander's model.

I measured the impedance of concrete experimentally with a spectrometer and tried to find the conductivity of the moist concrete sample. I plot the conductivity curve with respect to frequency, however, the curve shows negative conductivity. How to explain the curve?

Two equal and opposite forces balance This is known. So if we apply corresponding compressive forces to the tensile forces, they will balance. This is the prestressing mechanism that static civil engineers use to achieve large bridge spans, so large that this would be impossible to achieve with simple linear reinforcement and the cooperation mechanism of concrete and steel, that of relevance that they use in construction. I will try to explain to you the reason.

As a span increases, the bending loads increase, so the tension and compression in the cross-section also increase. To receive the compression, we increase the concrete, that is, we increase the cross-section height. When I increase the dimensions of the cross-section, the loads also increase. To receive the loads we also increase the steel reinforcement. Steel has superior tensile strength, but to receive the tension it needs the help of concrete. That is, the concrete must have the ability to hold the steel inside it when it pulls from the right and left so that the steel does not slip through the concrete and their cooperation is broken. This pulling force applied at the interface of the two materials of steel and concrete is called shear.

The concrete not being able to withstand the shear caused by the pull of the steel breaks, their cooperation is lost and the bridge falls. As the span of the bridge increases, so we increase its mass and its loads, but without having the possibility to increase above a limit the strength of the concrete coating in terms of shearing. This is why we cannot construct large spans of 50 meters in bridges with the simple linear reinforcement that we construct in buildings. Concrete with the simple reinforcement method of this relevance has a problem because it cannot withstand the shear caused by the high tensile strength of the steel. Concrete, however, has superior strength in receiving the torsional force. So what do we do? We apply large compressive forces to the cross-section to neutralize the tensile forces and balance the forces and this means that along with the tensile forces we have also neutralized the shear forces at the interface of the concrete and the steel, since we have neutralized the tension that causes them.

In large earthquakes the seismic loads are three times the static loads. The shear failure of the concrete is given by the tripling of the stresses In order for this not to happen, the static civil engineers must apply prestressing to the walls and not only place reinforcement of the relevance With only two prestressing tendons on the slopes of the walls, they would replace 80% of the linear steel reinforcement, reduce the concrete cross-sections and increase the earthquake resistance of the structure. The other crazy thing that the statics do is that they try to stop the large moment of the overturning of the walls, which comes from the inertia of the vertical slabs, with the cross-sections of the slabs, without drawing external balance forces from the ground. If the prestressing tendon we just mentioned were anchored to the ground and not to the base, then all the forces of the overturning moments would be diverted into the ground and the cross-sections of the slabs would not break.

The shear base cuts the cross-sections of the walls near the base, and its force is equal to the magnitude of the acceleration, multiplied by the mass of the structure. This is also the power of inertia of construction. The cross-section of the wall increases its strength in relation to the shear base by 40% when we apply compression to the cross-section of 70% of the breaking point of the concrete. Basic and well-known engineering data which, for some unknown reason, do not apply to the statics of earthquake-resistant structures. Still compacting with the ground ensures a strong foundation.

Maybe we need to look back at Roman Concrete and modernise it for present day use.

During concrete casting works in construction projects, there are several factors that affect the quality of concrete on-site, some of which are related to the supplier concrete, some of them are related to casting workers, and the other is the implementation of wood molds and reinforcing works.which the factor was critical

Trying to mitigate early-age fractures in concrete buildings is crucial for ensuring adequate durability, minimising potential strength loss, and lowering maintenance costs. Because these cracks challenge the residential comfort and the aesthetic appearances of buildings.

Hi,

Most of the research about the ITZ claims that this zone has a significant effect on concrete mechanical parameters, so I was wondering if there are any models connecting the concrete compressive strength with this ITZ.

Thanks.

suppose I want to adjust X kg with the water given .How to do it.( please explain it only the process without math calculation)

Recently, i have been subjected to many rejection for the reason of novelty which does not making sense at most. I came through the following abstract in the aforementioned journal and although my manuscript is discussing very importnat applicable topic in porous concrete i came through recent published and accepted article with the below abstract.

Calcium sulfoaluminate (CSA) cement can be used as a replacement for Portland cement to reduce CO2 emissions. However, the performance of CSA cement remains unknown with regard to its hydration mechanism, mechanical and long-term performance. Therefore, it would be beneficial to consolidate the literature on CSA cement to facilitate its use in the construction industry. To this end, recent progress and technical challenges of using CSA cement are discussed in this paper. We begin with the introduction of the different types of CSA cement and the manufacturing process. This is followed by a detailed discussion on the hydration mechanisms and phase assemblage, mechanical performance, and long-term durability of CSA cement. Finally, the applications of CSA cement are discussed.

My question does the journal accept or reject papers on the basis of relationship and politics is the research include also some corroupted and bais basis.

Please i would like to be answered for once

The idea that posttensioned wires don't have splices

I am really curious to know why we make clinker in oxidizing conditions? of course because of burning the fuel for the kiln but do the environment really affects the clinker quality.

regards

Saurabh

Is it possible to use concrete with different percentages of iron to protect the walls of neutron therapy room?

We working on translucent concrete. Could anyone help us giving the vendor/supplier details for using in translucent concrete? Thanks in advance.

As it is evident, concrete production industry, especially cement has put the environment in a crucial situation via greenhouse gas production, as well as natural resources (e.g., sand) consumption. what could be done in order to make a shotcrete mix design more sustainable in order to achieve a good properties (e.g., mechanical, workability, etc.) product with less environmental footprints?

Many thanks,

Hossein Pouresmaeil.

I was performing a cyclic hollow pile to pile cap connection using ABAQUS, I use concrete damage plasticity (CDP) and static general analysis in my model. Some videos on youtube suggesting that since I use CDP which has a softening branch, the static general analysis will not included the CDP parameters I input. You can watch on the link below at minute 10.00 for detailed information. Should I use a static of dynamic analysis?

Which textile hardwaste can be reused easily in concrete material?

The material properties of the rebar and concrete are set to be completely elasto-plastic. However, the yield stress is exceeded at the integration point of concrete.

How can I prevent the yield stress from being exceeded?

The coefficient of friction is 0.3.

Thank you in advance.

How to write the python script for Strength of Double Skin steel concrete composite wall using Artificial Neural Network. I have attached the figure for your reference.

IS 456 recommends not more than 25ml of Sulphuric acid to neutralize water. Why is it so?

I modelled a hybrid column wiith concrete column at the center surrounded by a stone material with friction interaction at the interface. After running Iam getting this error.

How to write the python script for Strength of Concrete using Artificial Neural Network in matlab?

hey all iam civil engineering student i have a major project in concrete can anybody suggest me a new topic regarding structure pleaseeee

I have read out a lot of paper about bendable concrete. please anyone can help me make concrete elastic or introducing shape regain able property in concrete after bending.

Dear All

Greetings

Can you please suggest a research area in Recent trends in Alkali activated concrete research?

having developed dry concrete, I will wait for your tips to establish sales in bags of 25-50 clograms.

A 200*200*400 mm concrete model is prepared in ANSYS. In this model, a crack must be introduced at the center and the growth in the crack is visualized using a smart crack tool. How to perform this?

Roads in desert areas are exposed to a set of deformations, the most famous of which are longitudinal and transversal cracks and ruting. This forces us to reconsider it early, and the local materials for road construction are not good in those areas. Is it possible to find a solution to this recurring problem? May you always be in the service of science and knowledge

Are there any standards available for preventive coatings for concrete for industrial and marine applications? Any information related to standards applicable for concrete coatings would be appreciated.

For sustainable construction activity a replacement of concrete as a construction material is becoming important than ever before. Almost 5 to 6 percent of carbon dioxide gases are attributed to cement industry alone and this is one of the biggest contributor to the pollution and carbon footprint. In addition to this the consumption of energy in making concrete and laying at site will further lead to carbon emissions. Life cycle use of concrete may further add to the consumption of energy.

The time has come when we need to focus on the alternate material of concrete which will have less carbon foot print and sustainable.

Is there any research available on Toughening Design of 3D Printed Concrete that is based on Machine Learning?

1. What are the relevant test used for detecting the crack healing efficiency in self healing concrete?

Some time ago me and my colleagues have published paper on lunar concrete made with the regolith simulant and low w/c ratio - the tests concerned the influence of regolith on the consistence of the mix ( ). I was thinking on the idea of making 3d printing trials.

Can you recommend papers on concrete 3d printing that might be helpful?

I would like to measure the impedance/ capacitance of the dielectric in order to find the moisture of the material by impedance spectroscopy. How can I ascertain that I am detecting (measuring) only the 'moisture content' of the material but not other properties?

How can I validate the value of impedance spectroscopy measured experimentally compared with the theory (or the experimental validation of the results through the theoretical analysis)?

Thanks in advance.

I would like to request the references which will be best to study the state-of-the-art of 'concrete moisture measurement' techniques:

(a) the measurement techniques can be included: both destructive and non-destructive methods,

(b) the state-of-the-art with electrical measurement techniques (resistive, inductive, capacitive, impedance spectroscopy).

Thanks in advance.

As a part of my PhD thesis, I am developing a UHFRC concrete mix based on locally available materials. After a few trials, I got 7-day compressive strength of concrete around 82 MPa. In the same cube specimens, we have observed many air voids of size around 6 mm. We are using a high-range water-reducing agent of 4%(HRWRA to cementitious ratio) having solid contents of 46%. If anyone phased such issues in your trials, kindly let me know how to avoid voids in the mix.

Thanks in advance.

Best regards,

Chandrashekhar Lakavath

Our execution team casted a raft foundation for an elevated tank, but the compressive results was not satisfactory with only 14 MPa after 7 days. we came up with many solutions but expensive, from your experience what could be the most cost effective solution?

Best Regards

I would like to request the references which will be best to study the state-of-the-art of 'concrete moisture measurement' techniques:

(a) the measurement techniques can be included: both destructive and non-destructive methods,

(b) the state-of-the-art with electrical measurement techniques (resistive, inductive, capacitive, impedance spectroscopy).

Thanks in advance.

Hi Engineers,

I would like to suggest a discussion,

Do you like classic or modern houses design?

do you like steel or concrete buildings design?

and why?

Hi, I want to estimate the service life of concrete. But I only have the sorptivity data and the bulk porosity data. Is there any model can be used to estimate the service life through sorptivity or porosity? I find most model are carbonation coefficient based or chloride ion penetration based. If not, can sorptivity be used to predict carbonation coefficient first?

Hello everyone. I would like to know if an experimental study is still valid if the number of curing days for concrete cylindrical testing will only be 7 days and 14 days. Your input will be highly acknowledged. Thank you