Cement - Science topic

Cement production is a major source of CO₂ emissions, contributing to about 7–8% of global emissions, primarily from the calcination of limestone and energy use. The best carbon capture technique for a cement plant depends on factors like process integration, cost, energy efficiency, and scalability. Below are the most promising carbon capture techniques for cement plants:

Mohammad Ali I would like to express my sincere gratitude for your valuable advice

Depending on the required pre-stressing, various types of fibers (synthetic and steel) and reinforcing bars can be used. The experiment measuring restrained expansion, in accordance with ASTM C878, employs a 5/16 in (5 mm) diameter bar inside a 10 x 10 x 3 in3 prism. Pre-stressing is proportional to the induced expansion within the matrix, which can be due to the use of expansive agents (CSA-, CaO-, and MgO-based) and their combination with internal curing materials for enhanced expansion. According to the Japan Concrete Institute (JIS A 6206) and other published literature, concrete with restrained expansion ranging from 150 to 250 μstrain is classified as shrinkage-compensating concrete, and concrete with restrained expansion greater than 250 μstrain is referred as chemically prestressed concrete (or self-stressed concrete). For more information you may study the article below.

Method A:

- Total volume: 1m³

- Volume of cement: 1/7 = 0.143

- Mass of cement: \( 3.1 \times 0.143 \times 1000 \) = 443 kg

- Weight of 5% SCBA: \( 0.05 \times 443 \) = 22.15 kg

Method B:

- Total volume: 1m³

- Volume of cement: 1/7 = 0.143

- Mass of cement: \( 3.1 \times 0.143 \times 1000 \) = 443 kg

- Weight of 5% SCBA: \( 0.05 \times 0.143 \times 2.8 \times 1000 \) = 20.02 kg

Correct Method:

Method A is correct because it straightforwardly calculates the 5% replacement of cement by weight. Here’s why:

- The 5% replacement is directly related to the weight of the cement, not to the volume.

- \( 5\% \) of the 443 kg of cement is indeed 22.15 kg.

In Method B, multiplying by the specific gravity of SCBA (2.8) along with the volume doesn’t align with the standard practice of calculating the replacement material by its weight proportion.

So, Method A: is the accurate approach to determine the weight of SCBA for a 5% replacement of cement in a (1:2:4) mix ratio.

Thermal insulation in cement bricks is typically measured by determining their thermal conductivity (k-value), which indicates how well the material resists heat flow. This is usually done using methods like:

The lower the k-value, the better the insulation properties of the brick.

Ye'elimite-rich cements, such as Calcium Sulfoaluminate (CSA) cements, offer several key benefits and challenges in construction.

Benefits:

1. Rapid Strength Gain: These cements achieve high early strength, which reduces construction time, making them ideal for projects requiring quick turnarounds.

2. Low Carbon Emissions: Compared to Ordinary Portland Cement (OPC), ye'elimite-rich cements generate lower CO₂ emissions during production, contributing to more sustainable construction practices.

3. Durability: They exhibit good resistance to sulfate attack and shrinkage, making them suitable for harsh environments.

4. Reduced Shrinkage: These cements minimize shrinkage cracking, improving the longevity and integrity of structures.

Challenges:

1. Limited Availability: Ye'elimite-rich cements are less commonly available, which can restrict their widespread use.

2. Cost: The production and sourcing of materials for CSA cements can be more expensive than OPC, limiting their economic feasibility in some regions.

3. Specialized Knowledge: Proper use of ye'elimite-rich cements requires specific expertise, as they behave differently than traditional cements in terms of setting time and chemical reactions.

Peaks often overlap. This is the case with C2S, C3S. This is one of the reasons to use the Rietveld method for XRD interpretation. Mixtures of cement with quarry sand is not a material for easy evaluation. Natural sand minerals tend to have significantly higher diffraction intensities, mainly quartz, and overlap the other components. The cement components disappear quite a bit.

This might help

In order for the cement to be sulphate resistant, the C3A content should not exceed 5 per cent. It is also desirable that the C3S content of the clinker should not exceed 50 %. The source of iron is iron-containing components. The source of iron can also be grinding balls and armour plates of ball mills, which are gradually eroded by abrasion during the grinding of the raw material mixture and fall into the raw material mixture. This increases the iron content of the raw material mixture for roasting.

How are you preparing your samples prior to TGA analysis? What temperature are you purging with Ar gas prior to the TGA run, what is your ramp cycle? What are you looking for, thermal degradation, moisture content, reaction kinetics? There are several companies that offer TGA equipment specifically for concrete and other ceramic-type or construction materials. These companies have procedures. Also, have you done a literature search? You are not the first to use a TGA with concrete.

Idham Kholid Rahmatullah to answer quickly at your question…NO!

Professor Davidovits has explained the reasons of that reaction. Geopolymerization doesn’t happen casually or because has been found a trick to block the efflorescence, but following precise mix design, that is practically the same using all different types of precursors and reagents. Reagent isn’t an activator because what is already well reactive is the powder part, so the pH is user friendly (I can send you videos where I put my fingers inside without gloves with no issues or burning). Don’t try to put your finger inside an activator for AAM, take care.

It isn’t a question of description but GP and Alkali Activation follow different ways. The leaching happens because for AAM the real ”glue” that keeps all together is the strong pH obtained by corrosive liquids or by metasilicate plus water (the result is still a corrosive pH of 14 or even 14+ if activators are used in higher quantity). The alkaline ions are over saturated and don’t react with nothing a part the CO2 in the air so migration and carbonation are normal consequences. The issue in this case is that sodium or potassium carbonates are salts not minerals like the Calcium carbonate that grows on the surface of Portland based recipes…so their solubility in water is total while for calcium carbonate is still very low.

Geopolymers has very thin carbonation because the reaction, between precursor and reagent to create the final GP binder, is well balanced so there aren’t free alkali that can move to the surface to become carbonates.

Check on YouTube there are already the videos where Prof Davidovits explains these and much other aspects.

Best

Alex

1. Laboratory Tests:

a. Physical Tests: These tests are conducted to assess the physical properties of cement, such as setting time, soundness, and consistency. Some common tests include Vicat needle test for setting time, soundness test using the Le Chatelier method, and consistence test using the Vee-Bee Consistometer.

b. Chemical Tests: These tests are performed to determine the chemical composition of cement and ensure it meets the required specifications. Some common chemical tests include chemical analysis (determination of oxide composition), sulfate content test, chlorine content test, and alkali content test.

2. Field Tests:

a. Compression Strength Test: This test is conducted to evaluate the strength of cement in concrete samples under compression loading conditions. Cylindrical or cubic concrete specimens are prepared and cured for a specific period before being subjected to compression testing.

b. Slump Test: This field test is used to measure the consistency or workability of fresh concrete mixtures by determining the slump value. The slump cone is filled with freshly mixed concrete, and after compacting, it is lifted to measure the amount of slump.

c. Air Content Test: This test is performed to determine the air content in freshly mixed concrete using methods such as the pressure method or vacuum method.

In both laboratory and field tests, proper sampling techniques are essential for obtaining representative samples that accurately reflect the properties of the cement or concrete mixture under investigation.

- Why don't I consider 50 ml dilution of aliquoted sample in the calculation equation ?

Because you are diluting both, sample and standard, to the same final volume of 50 mL.

If you decide to dilute your sample to 100 mL instead of 50 mL, this means that the concentration value that you will get from the calibration curve must be multiplied by a factor of 2 (because the sample is now twice more diluted than the standards).

Your proposed use implies that ground hyacinth powder has chemical binding properties. I do not have experience with this material, but in my work with mortars for use with fired clay and cementicious masonry, cement and lime are mixed with sand in varying proportions to achieve a range of strength and stiffness properties. I recommend researching to find, or developing, information on the chemical binding properties of ground water hyacinth powder that could be compared to cement. Another possible strength contributing property for use with rammed and adobe blocks is plant fibers in the ground water hyacinth material. If the fiber is not ground too finely, this could be similar to the addition of polypropylene or metal fibers to concrete mixes.

Joaquin Abellan-Garcia The 'D50' is a median particle size not a mean. The relation between SSA and the Sauter Mean Diameter (Surface Area Moment Mean) is D[3,2] = 6/SSA with the appropriate units. See, for example:

and the attachment.

For packing, see this webinar (free registration required):

In pursuit of perfect packing

The intrinsic strength of cement gel is an important property that governs the overall strength of cement-based materials. The intrinsic strength refers to the inherent strength of the cement gel, which is the primary binding phase in cement paste. Here are a few methods commonly used to determine the intrinsic strength of cement gel:

It's important to note that the intrinsic strength of cement gel can vary depending on factors such as the water-to-cement ratio, curing conditions, and the presence of supplementary cementitious materials. Additionally, the measurement of intrinsic strength can be challenging due to the heterogeneous nature of cement gel and the difficulty in isolating it from other phases present in cement paste.

Medan företagande kan ses som en mer operationell verksamhet och ofta innebär att bygga vidare på befintliga affärsmodeller.

Är entreprenörskap mer inriktat på att skapa något nytt och annorlunda som kan ha en större påverkan på marknaden.

Hi Dr. Felix M. Delmonte,

Thanks for such a comprehensive and detailed response. It covers all aspects to ensure fiber's homogeneity in a composite matrix.

Regards,

Farhan

All of these methods are good but you take care about the sampling method and had better sampling by an expert.

Several factors make GGBS a more favorable choice for partial cement replacement compared to Pulverized Fuel Ash (PFA) in concrete.GGBS exhibits better early-age strength development compared to PFA, making it preferable for applications requiring faster strength attainment.GGBS concrete shows superior resistance to sulfate attack compared to PFA concrete. This is crucial in aggressive environments with high sulfate content, where concrete longevity is essential. While PFA can enhance chloride resistance to some extent, GGBS offers better protection against chloride ingress, which is critical for structures exposed to marine environments.GGBS typically requires less water for mixing compared to PFA, leading to more workable concrete with improved cohesiveness and reduced risk of segregation.

Kindly refer to the references given below:

Ground Granulated Blast furnace Slag (GGBS) as a Cement Replacement Material" by M. R. Jones and R. K. Iling (2003) - https://www.researchgate.net/publication/235607211_Use_of_Granulated_Blast-Furnace_Slag_in_Concrete_as_Fine_Aggregate

"High-Performance Concrete: Sustainability and Efficiency" by Mario Collepardi (2019) - https://www.sciencedirect.com/topics/engineering/high-performance-concrete

"Concrete: Cement Substitutes - GGBS, PFA and more" by GreenSpec - http://www.greenspec.co.uk/what-we-do/

"Ground granulated blast-furnace slag (GGBS) cement uses" by Wikipedia - https://en.wikipedia.org/wiki/Ground_granulated_blast-furnace_slag

Oleg Novikov

Уважаемый господин,

Спасибо за ваш ответ.

Не могли бы вы вкратце объяснить причину окисления и то, как это окисление приводит к увеличению концентрации хрома с фактических 12 % до 25 % в этом черном пятне.

plastic pavement is eco-friendly. I did a research on this in my Undergraduate level

Hello.

I think I can help you with this task. About the percentage of amorphous phase, I must review the methods to determine it, but I think we can handle this.

Sincerely,

Ricardo Tadeu

pH 13.3 corresponds to an ionic strength of 0.2M. That is too high for any commercial instrument to measure reliably (I don't care what PR claims they might make). I know with my Zetasizer and the dip electrodes that attempting such measurements will almost certainly degrade the electrodes. There may be no gas evolution - that's because the electrodes are made from palladium. Instead of gas, they produce nice colloidal palladium particles! I have published evidence of that.

I have developed an instrument that can reliably measure up to 6M ionic strength. I'm also based in North Carolina. I invented the PALS method used in many commercial instruments so I know how it should be done properly.

Feel free to contact me either via RG or at john@enlightenscientific.com

AFT (Accelerated Carbonation Test): This is a laboratory test used to assess the carbonation resistance of concrete. Carbonation is a chemical reaction where carbon dioxide from the air reacts with the calcium hydroxide in concrete to form calcium carbonate. AFT helps in predicting how well concrete will resist carbonation over time. AFt (Alumina Ferric Tri-sulfate): In the context of cement, AFt is one of the phases that can form in certain cementitious systems. It is a hydrate phase that includes aluminum, iron, and sulfate. AFt is often associated with the hydration of Portland cements containing significant amounts of sulfate.

The reaction takes place at the atomic or molecular level for the hydration reaction, and it works to accelerate the reaction, and this can be detected using a scanning electron microscope.

ِِDear Omidi

In my experience, when adding acid does not help, it is best to crush the sample with pliers (with the striate surface of the mouth) until the mud is removed from the sample. Then place the prepared sample in water for 48 hours, then grind the appropriate sieve sample under water for a few minutes. This method is helpful for separating the sediment on the isolated form in hard samples

Imo, you need to make initial trials for your particular mix. The effectiveness of the admixture depends on many factors, ranging from the w/c value, through the type and class of cement and the grain size of the aggregate. There is no one answer.

According to IS 10262:2019, a concrete mix designed for a 50 mm slump (using 20 mm aggregate) should contain 186 kg of water per cubic meter. A 25 mm increase in slump necessitates an additional 3% of the standard water content, equivalent to a 0.6% increase for every 5 mm change in slump. To adjust the slump without increasing water content, using a plasticizer is recommended.

Ferro-cement toilets are a type of sanitary facility constructed using a technique of reinforced mortar. These toilets are relatively easy to build, durable, and are often used in situations where more conventional toilets aren't practical, such as in rural or underdeveloped areas. The operation mechanism of a ferro-cement toilet is quite simple and can be categorized into a few stages:

### Construction:

1. **Skeleton Making:** A skeleton structure is built using steel mesh or chicken wire and then shaped as desired. It can be formed into various shapes and sizes.

2. **Cement Work:** The skeleton is then covered with a thin layer of mortar (cement mixed with sand and water). This forms a durable structure once dried.

3. **Finishing:** Once the cement is cured, it is waterproofed and sometimes tiled for aesthetic and hygienic reasons.

### Operation Mechanism:

The operation mechanism of a ferro-cement toilet can be understood in several key stages:

1. **Use of the Toilet:** The toilet is used in a conventional manner.

2. **Waste Collection:** Depending on the design, waste may be directed to a pit, septic tank, or another kind of waste management system.

3. **Waste Treatment:** The waste undergoes natural decomposition, and if a septic system is used, solid waste is broken down in the septic tank.

4. **Waste Disposal/Use:** Liquid waste (effluent) is generally allowed to percolate into the ground. If the system is designed for it, solid waste might eventually be removed and used as compost.

### Maintenance:

- **Cleaning:** Regular cleaning is essential to maintain hygiene.

- **Checking:** Periodic checks for cracks and other damages to ensure that the ferro-cement is holding up.

- **Desludging:** In the case of pit toilets or septic tanks, periodic desludging may be necessary to remove solid waste when the system gets full.

### Advantages:

- **Durability:** Ferro-cement structures are robust and weather-resistant.

- **Cost-Effective:** They are relatively cheap to build and maintain.

- **Sustainability:** Can be implemented in regions with limited resources.

- **Adaptability:** Can be shaped and sized as per requirement.

### Challenges:

- **Manual Scavenging:** In some instances, manual desludging might be required which poses health and social risks.

- **Waste Management:** Safe and hygienic waste disposal/treatment must be assured.

- **Cultural Acceptability:** Sometimes, communities might be reluctant to use them due to socio-cultural beliefs.

Always note that the efficiency and health safety of any toilet system, including a ferro-cement toilet, largely depend on good maintenance practices and appropriate use. This ensures that the waste is managed effectively, and hygiene is maintained. Furthermore, waste should be handled, treated, and disposed of in a way that is safe for both people and the environment.

Hello

The effect of nanoclay on the strength will mainly depend on the percentage weight of nanoclay added and the type of cement material you are using as well as which type of strength you are measuring (compressive, tensile, flexural, impact, ...).

This is a very interesting review about the effect of nanoclays as fillers on different material properties.

السلام عليكم دكتورة امال العزيزة تكدرين اتروحين لقسم المعمار النهرين اكو دكتورة متخصصة بالبرنامج اجوبك على كل الاستفسارات تقبلي تحياتي@

MD simulations cannot be done for such a long time scale. If you implement several crude approximations you will not be able to get any useful data(provided you are able to perform it in the first place).

No, in EN 196 the water to binder ratio is fixed at 0.5, irrespective of the flow that you get. The proportions given in the original question are correct. You are allowed to use superplasticizers to compensate if you're using, for example, a cement with high water demand.

What is described above is the ASTM (C109/C109m) approach to standard mortar testing, where you aim for a uniform consistency in the flow table rather than a fixed water to cement (or binder) ratio. Which approach is better or worse is a completely different (and sort of endless) discussion that is still ongoing, but those are the two main trends.

Adding brick powder to cement can have a number of benefits, including:

The optimal addition percentage of brick powder depends on the type of concrete being used and the desired properties of the concrete. However, a typical addition percentage is 10-20%.

Here are some additional benefits of adding brick powder to cement:

Overall, adding brick powder to cement can have a number of benefits. It can help to reduce the cost, improve the strength, durability, workability, and fire resistance of concrete. The optimal addition percentage of brick powder depends on the type of concrete being used and the desired properties of the concrete. However, a typical addition percentage is 10-20%.

Good question.

I find that some of the most exciting topics I studied were often those into which I stumbled accidentally and not really by prudent planning, hence, I feel that it might be a wise strategy to follow two strands:

1) just follow your gut feeling and your nose and keep your eyes open on unexpected and strange and outlier type of phenomena where real scientific gold nuggets might be hidden, so to say, watch out off the beaten track.

2) looking for large scale societal needs on the other hand may indeed also be a pertinent strategy because I sometimes feel that our materials science community is a bit conservative and not really taking many risks in such areas nowadays, often rather following topics in which the (expected) impact is relatively high. My personal taste in this category are for instance research topics related to materials related questions such as (a) sustainability/ sustainable metallurgy / sustainable cement etc (i.e. real reduction of carbon dioxide emissions, beyond the usual bla bla); (b) materials for future water supply; (c) machine learning in material science and engineering ; (d) large (huge) scale energy storage for buffering abundant sustainable and grid electricity (i.e. Not just lithium based batteries for vehicles; but land based huge storage capacity): (e) electrochenistry and corrosion of materials (i.e. longevity) etc. etc.

I feel that - for getting good ideas in such directions - it is sometimes more helpful to read financial and business newspapers rather than our usual community material science journals, which, as I mentioned before, are sometimes chasing citation-measured impact alone but not real relevance for society and industry and not real curiosity-driven topics that sit between the established chairs. Open your eyes and look around you and think urself what your local, wider, or global society really needs from us materials scientists? Ideas will then come en gros.

Good luck.

One example what I chase at the moment :-)

I would agree with the answers above. Setting time depends on a multitude of factors. Each project should determine how long a set time they need and then design the mix to set within the desired time span. The effect of admixtures is hard to predict. I had a case where we took a regular water reducing agent, dosed it at twice the manufacturer's recommended dose and achieved excellent retarding effects. In that case we delayed the set time for several hours (we had to transport concrete from a batch plant to a loading dock, transfer it by crane and bucket to barges fitted out with agitating hoppers, tow the barge to concrete placement site, and then place it with a crane barge and buckets in the piers), but we had rapid strength development after that.

So the practice to follow is to determine your requirements then design your mix.

One comment about superplasticizers: They typically increase the workability for about 30 minutes, then need to be re-dosed. You can add superplasticizers several times as the effect wanes.

I can think of many ways of using plastic waste to stabilize soil particles and improve cement-grade properties. Plastic wastes can include polythene, compound plastics, wrappers, and so on. One can stitch plastic pieces tightly with unconsolidated soil and apply various nominal stresses and shear forces. 1000-1500 Kpa can be tried at first with plastic-strips boundary at 5mm thickness and 1000 mm span. With notice taken to clay with 0.001 mm particle sizes, require the greatest compression to get rid of void pressures and hydrostatic pressures. Gravel has a large particle size of around 0.2-0.5 mm and requires less compaction. It can take a very long time to consolidate clay. One can increase plastic strips' density by wrapping soil particles with a thickness that can be increased for holding stresses. The holding stresses can be increased to 2000-3000 Kpa, with greater interbinds to hold silt or clay particles. The thickness of the plastic strips has to be increased to prevent rupturing and particle leaks. Solid plastic can be crushed and grid with asphalt, silt, and clay to make cement.

Depending on the percentage composition of the mix, compaction tests can prove the strength and yield of the different cement mixes.

mixing liquid sulfur into concrete mix would introduce incompatible materials and could negatively impact the performance of the concrete.

It is not a book, but also try:

Cement and asphalt are the most common ingredients in constructing roads, driveways, and other surfaces. Many people believe these materials can be used in the same concrete mix to improve the properties and performance of concrete. Cement is typically used as the primary binding agent in concrete mixtures and is often blended with other powdered materials, such as sand and gravel, to create a more robust, more effective finished product (Liu et al., 2018). Conversely, asphalt is a product of refining crude oil primarily used as a binder, waterproof, and protective surface layer (Jerez et al., 2019). The two materials are conceptually distinct in design and application. However, there are some areas where their properties overlap and could be used in the same mix. Proponents of combining cement and asphalt in a concrete blend suggest that the combination will yield a highly durable and resilient material that can withstand adverse weather and traffic conditions (Peña et al., 2020). Additionally, combining the two materials can reduce costs associated with a project by reducing the maintenance and upkeep required (Liu et al., 2018). However, combining two binding agents can also have adverse effects. It has been noted that mixing cement and asphalt can decrease the strength of the concrete and reduce its overall durability (Martin, 2019). Additionally, the combination has slightly increased asphalt's elasticity, diminishing its already lower strength (Peña et al., 2020). Combining cement and asphalt in a concrete mix can have advantages and disadvantages. On the one hand, it can reduce costs associated with a project and yield a highly durable and resilient material capable of withstanding adverse weather and traffic conditions. On the other hand, the combination can negatively affect the strength and durability of the cement. Ultimately, it is up to the builder's discretion to determine if this combination of materials is the right fit for their project.

References:

Jerez, P., Acevedo, D. M., Siles, A., Timoteo, A., & Romero, S. (2019). Construction of asphalt roads using recycled materials: a review. Journal of Cleaner Production, 206, 174–190. https://doi.org/10.1016/j.jclepro.2018.10.247

Liu, B., Wang, S., Xie, H., & Kuang, Y. (2018). Effects of cement-soil mixing ratio on properties of cement-treated soil. KSCE Journal of Civil Engineering, 22(3), 1301–1308. https://doi.org/10.1007/s12205-016-0523-2

Martin, M. (2019). Advantages and Challenges of Asphalt Cement and Concrete Mixes. eHow, ehow.com/info_8630519_advantages-challenges-asphalt-cement-concrete-mixes.html

Peña, E. A., Angeles, E. V., Cruz, L. M., Hernández, M. A., & Rodríguez, O. J. (2020). The durability of asphalt concrete containing high levels of limestone powder. Construction and Building Materials, 239, 117868. https://doi.org/10

Using recycled construction wastes in concrete or decarbonized cement could be an ideal intervention provided that the demand side could be adressed and/or realized. Producing cement using renewable energy sources could also compliment the first option with significant mitigation impact.

Thank you.

aysheshum.abebaw@aau.edu.et

Rajden Skhvitaridze, I meant binders not included in the standard.

In a thin section slide of a sandstone, cement and matrix are two important components that can be distinguished based on their mineral composition and texture.

To differentiate between cement and matrix in a thin section slide of a sandstone, you can use a polarizing microscope. Under polarized light, the cement and matrix will exhibit different colors and textures, allowing you to distinguish between them. The cement will appear brighter and more crystalline, while the matrix will appear duller and finer-grained.

Overall, understanding the difference between cement and matrix is important for interpreting the depositional environment and diagenetic history of a sandstone.

You are correct that the production of Portland cement is responsible for significant CO2 emissions, with approximately 0.8–0.9 kg of CO2 emitted per kg of cement produced. The use of waste materials as partial replacements for cement, such as rice husk ash, fly ash, coconut shell ash, water hyacinth ash, bamboo leaf ash, and sugarcane bagasse ash, has been studied as a means to reduce these emissions. While the burning of these waste materials does produce CO2, the overall emissions tend to be lower than those associated with traditional cement production.

Quantifying the exact reduction in CO2 emissions from using these waste materials as cement replacements can be challenging due to several factors, including:

In many cases, the focus of research papers is on the mechanical properties and durability of concrete made with these alternative materials, rather than providing exact numbers for CO2 emissions reductions. However, it is generally accepted that utilizing waste materials as partial cement replacements can lead to a reduction in overall CO2 emissions, as these materials often have lower carbon footprints compared to traditional Portland cement production.

To obtain more specific numbers on CO2 emissions reductions, you may need to look for studies that have conducted life-cycle assessments (LCAs) for concrete made with these waste materials, as these assessments consider all aspects of production, including CO2 emissions.

I hope this helps!

Sasui,

Hydration reaction is one of the most critical processes in cementitious materials manufacturing. During this process, cementitious materials are mixed with water and undergo a chemical reaction that produces a hard, strong material. Stopping the hydration reaction of cementitious materials is essential for many reasons. This essay will discuss the importance of stopping hydration reaction, the methods of stopping hydration reaction, and the effects of stopping hydration reaction on the properties of cementitious materials. A stopping hydration reaction is significant because it can extend the life of cementitious materials. When cementitious materials are exposed to water, the particles react with each other and form a solid mass. This reaction is known as hydration. If not stopped in time, it can lead to material deterioration. By halting the hydration reaction, the cementitious materials can be preserved for longer periods and be used for a longer lifespan. There are several methods of stopping hydration reactions in cementitious materials. One of the most common methods is to use a curing agent. Curing agents are chemicals added to the mix and react with the cementitious material to prevent the hydration reaction. Another method of stopping the hydration reaction is to add a sealant or coating to the cementitious material; This can prevent water from coming into contact with the material and thus prevent the hydration reaction. Finally, temperature control can also be used to stop hydration reactions. The rate of hydration reaction can be slowed down by controlling the temperature. Stopping the hydration reaction of cementitious materials can have a significant effect on the properties of the material. By controlling the hydration reaction, the cementitious material can maintain its strength and durability for longer. Also, hydration reactions can cause the fabric to shrink, leading to cracks and other structural problems. By stopping the hydration reactions, these problems can be avoided. Stopping the hydration reaction of cementitious materials is essential for many reasons. By halting the hydration reaction, the life of the material can be extended, and problems caused by the hydration reaction can be avoided. Stopping hydration reaction can be done using a curing agent, sealant or coating, or temperature control. Finally, blocking hydration reaction can significantly affect the material's properties, such as increasing its strength and durability.

References:

Ahmed, B., & Ghosh, S. (2020). Stopping Hydration Reaction of Cementitious Materials: A Review. Construction and Building Materials, p. 248, 117909. https://doi.org/10.1016/j.conbuildmat.2020.117909

Chen, J., & Li, M. (2020). Effects of curing temperature on the hydration process of cementitious materials. Construction and Building Materials, p. 228, 116420. https://doi.org/10.1016/j.conbuildmat.2019.116420

Hossain, M. R., & Samarah, N. H. (2020). Effect of Curing Agents on Hydration of Cementitious Materials: A Review. Materials, 13(8), 1619. https://doi.org/10.3390/ma13081619

What do you mean by "cement paste with the water content proportional to the amount of water in the mortar mixture"? Do you need to design the paste of the same consistency or strength? Because each needs other approach to the task.

Thank you, my teacher Thank you, my teacher

Cement is an essential material for many construction projects, and its use has increased as population growth and urbanization increased. However, cement production is a significant source of carbon dioxide emissions and energy consumption, significantly contributing to climate change. As such, finding ways to replace cement with other materials partially is essential for sustainable and environmentally friendly construction. Research shows that the partial replacement of cement with other materials can improve the performance, durability, and environmental impact of construction materials and reduce the overall carbon footprint of the construction process. For example, fly ash, a byproduct of coal burning, can reduce the need for cement by up to 35%. In addition, other materials, such as slag, silica fume, and natural pozzolans, can be used to partially replace cement, with percentages ranging from 5% to 30%. When considering partial cement replacement, it is essential to evaluate why to start at 5% and what the 5% increment is. Starting at 5% is important because it allows researchers to gradually increase the replacement percentage while assessing the concrete's performance. Starting at a higher rate may lead to unexpected results, as the performance of the concrete may be better than initially anticipated. The 5% increment is essential as it allows researchers to gradually increase the percentage of replacement in small steps and assess the changes in performance. In conclusion, the partial replacement of cement with other materials is a critical way to reduce the environmental impact of construction. Research has shown that using different materials to replace cement partially can improve the performance, durability, and environmental impact of construction materials while reducing the overall carbon footprint of the construction process. When considering the partial replacement of cement, it is essential to evaluate why to start at 5% and what the 5% increment is to ensure the performance of the concrete is as expected. References: 1. Bhuian, S.N., and Abdalla, M. (2008). Cement replacement materials. Cement and Concrete Composites, 30(10): 667-673. 2. Sivakumar, M., and Murugan, R. (2013). Partial replacement of cement with fly ash. Indian Journal of Science and Technology, 6(10): 4491-4495. 3. Sharma, M., and Sharma, A. (2018). Partial replacement of cement with Silica Fume and Slag in concrete. International Journal of Engineering Research and Technology, 7(7): 1101-1105. 4. Hadi, M.S., and Ammar, M.A. (2010). Partial replacement of cement with natural pozzolan in concrete. International Journal of Engineering Research and Technology, 1(2): 13-18.

Thanks for your question, leachate testing for the solution concentration may be one of the options of for measurting the potential DEF-expansion. Please find the details in this manuscript.

To calculate the energy savings from replacing L-W absorbing cement flooring with epoxy light-wave reflecting cement flooring, you need to consider the following steps:

where:

It's important to note that the results of the calculation will depend on several factors such as the location of the building, the orientation of the flooring, and the climate. It's always a good idea to consult with a professional engineer or energy analyst to get a more accurate estimate.

Yes, you can use Ultrasonic Pulse Velocity test to determine the parameters of non-cement concrete materials such as rock or limestone. You can measure the parameters using ASTM standard: Standard Test Method for Laboratory Determination of Pulse Velocities and Ultrasonic Elastic Constants of Rock D 2845 – 00. This test method describes equipment and procedures for laboratory measurements of the pulse velocities of compression waves and shear waves in rock and the determination of ultrasonic elastic constants of an isotropic rock or one exhibiting slight anisotropy.

The internal stress of a natural rock may be less than or equal to and higher than loaded stress, this depends on the internal heterogeneity and defect distribution of the rock. The discrete element method can analyze the stress transfer of rock and soil.

Dear,

I suggest to use a wetting agent to engage better the aerogel inside the mixture. There are several types on market that work very well, but dosages can change depending on concentration of reactive content.

I think you could check about BASF portfolio.

These products can work at best if supported by polycarboxylates superplasticizer to manage the high amount of mixing water.

Best

Alex Reggiani

I cannot comment on this specific case, since this is not my domain of expertise, but I can add that some publishers do not care very much about the quality, novelty or whatever we may consider as quality indicator. For some of the open access journals (generalisation is not fair here as in many other situations), what matters is the payment of the processing fee.

I have the experience of reviewing for one publisher that claims to have papers published slightly above one week after reception, which is phantastic. The point is that reviews are mostly a make-believe action.

A few months ago, I was invited to make a review for one of those journals and was asked to do it in 10 days (after I having said that one week time was too short). After one week, the publisher had already two extremely superficial reviews that accepted the paper without major modifications, while discarding mine that added a 30 points list of arguments to reject it. The paper was published, and I never again accepted the many invitations they are continually making.

Therefore, we must read each new article with a critical sense and not accept that everything written can be taken as valid.

If the clinkerization reaction (the process of forming clinker, the main component of cement, from raw materials such as limestone and clay) occurs in a reducing environment, the quality of the cement may be affected. In a reducing environment, the iron in the raw materials may be reduced to metallic iron, which can cause the cement to be less durable and less resistant to sulfates. Additionally, the formation of metallic iron can lead to a decrease in the overall strength of the cement. Therefore, it is important to maintain an appropriate level of oxygen during the clinkerization reaction to ensure optimal cement quality.

'To make a shotcrete mix more environmentally friendly, replace part of the Portland cement with supplementary cementitious materials, such as fly ash or slag cement. Using recycled aggregates and reducing the water-cement ratio can also help shotcrete have less negative impact on the environment. For example, the use of fly ash instead of half the cement can significantly reduce CO2 emissions. It is possible to further reduce the overall environmental impact of shotcrete by taking into account its life cycle, including the amount of maintenance required. The environmental impact of shotcrete can be reduced by curing it with wet burlap or burlap cloth, which requires less energy.'

Silica Fume;

Water to cement ratio influences concrete permeability,

Etc.

Yes, helium pycnometry will work. If you want to stick with the volumetric method, you can substitute for the kerosene with an alcohol. See for example:

Comparative study of methods to measure the density of Cementious powders.

This paper can also be found on ResearchGate.

Good luck,

Dale

thank you sir Shashikant Kumar for you recommendations

The most recent versions of the CEMDATA database contain a subset dedicated to alkali-activated materials. If I'm not wrong, that database uses zeolites as proxies for N-A-S-H phases. Alternatively, you can create your own set of phases that are relevant in AAM. For reference, you can browse my publication:

Here, you'll be able to find a table with thermodynamic parameters for some relevant phases, comprising N-A-S-H (I used a two end-member solid solution), metakaolinite and alkali carbonates (thermonatrite, trona, pirssonite, gaylussite).

Once it enters your lungs there is a potential for numerous short and long-term problems. Particularly if it is un batched, the list is very long, research on this basis.

I would suspect that it would not be that different from OPC, whose value can easily be found in the literature. If you want an easy way to estimate its value, assuming you do not have thermoanalytical equipment (such as a Hot Disk) to make the measurement, you can easily construct a simple calorimeter using a beaker of solution of known heat capacity (an alcohol for instance, don't use water as it will react with the cement). Then, weigh the beaker empty, with the solution added (measure its temperature as well), and finally after adding the cement powder that it is first heated to an elevated (known) temperature (below the boiling point of the liquid of interest). Measuring the final temperature of the mixture in the beaker will allow a quick calculation via an energy balance (m1*deltaT1*Cp1=m2*deltaT2*Cp2) of the unknown heat capacity (neglecting any energy that is added if you stir the mixture, for example --- could further estimate this effect by performing experiment on a powder of known heat capacity...).

Geopolymers can be synthesized at low temperatures (25–80 °C) using an alkaline solution and an alumino-silicate material. Materials including amorphous silica, alumina, and alkali hydroxide (NaOH/KOH) are commonly used in the synthesis. For the synthesis of the binder, a variety of aluminosilicate materials can be employed. Metakaolin, rice husk ash, fly ash, and volcanic slag are among them.

From the perspective of cement, graphene oxide is just expensive soot. Soot has been added to cement in studies like this one:

A serious study would therefore compare:

a) no addition of soot

b) generic, chemically non-specific soot

c) fancy and expensive soot (aka graphene oxide)

By the way, In Poland we hardly ever use pure Portland cement in ordinary concrete - we often use the cements with fly ashes or blastfurnace slag.

An interesting topic!

Maybe...you can calculating manually the Relative Atomic Mass

Thank you very much for the answer. I have already seen overestimated Al2O3 wt. % in the quantitative analysis. But, I was struggling to get the amorphous content from the overestimated values. I will follow your recommended procedure. Thanking you again.

Hi, the liquid does not have to be changed for each test (fortunately because that would be complicated). The european standart EN 196-6 states "The manometer liquid shall be changed (or cleaned) after servicing or before a new calibration".

Note that you should calibrate the apparatus with reference materials (cement of known specific surface area). The apparatus constant shall be recalibrated with the reference material when another type of manometer fluid and/or a new manometer tube have been introduced.

Best wishes.

Maxime

Yes it has an annealing affect.it reduces the residual compressive stresses of cemented carbides.It will reduce the fracture toughness and flexural strength.Annealing in contrast will usually counter the strengthening effects of added reinforcements.Please do some review of annealing effects on cermets.

Depending on the annealing temperature and isothermal dwell time results can vary.

Buy a gas chromatograph for $250,000 and you'll know everything in no time

LOL....Mikhail

Often, a useful review paper can be produced efficiently if the following two conditions are met:

1) The paper does not already exist in the literature, and

2) you are starting a new research area and performing an extensive literature search so that you can get up to speed on the topic.

Defining of the scope of the review paper is still often a challenge, too broad and you won't be able to efficiently and effectively cover the topic(s) and too narrow and it will be of limited interest to the research community at large.

In addition to review papers, online bibliographies and annotated bibliographies for a research area can also be of interest and extreme value to others working in your field.

Happy review paper writing,

Dale

Effect of Different NaOH Solution Concentrations on ... - MDPI

https://www.mdpi.com › pdf

PDF

by Z Huang · 2021 · Cited by 1 — According to different ferronickel alloy production methods, ferronickel slag can be classified as electric furnace ferronickel slag (EEFS)

Brunauer–Emmett–Teller (BET) analysis is only specific surface area determination, that is why you got surface units (m2) over the specimen mass.