Cement Research Papers - Academia.edu (original) (raw)

With the advent of nano technology, materials have been developed that can be applied to high performance concrete mix designs. Nano silica reacts with calcium hydroxide (CH) to develop more of the strength carrying structure of cement: calcium silica hydrate (CSH). In this paper, relationships have been developed to distinguish the benefits when using different sizes of nano silica in cement paste. An extensive regime of experimental analysis was carried out to determine the effect of nano silica. Through these experiments the heat of hydration of multiple cement mix designs was measured. After that, the concentration of CH was recorded through X-ray diffraction. Then, the grain structures were examined through Scanning Electron Microscopy. Finally, the compressive strength was determined for each cement paste mixture. Through these experiments it was found that as the silica particles decreased in size and their size distribution broadened, the CSHs became more rigid; this increas...

- by
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- Civil Engineering, Materials Science, Nano, Cement
- by Deborah Chung
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- Civil Engineering, Materials Science, Water Treatment, Building
- by Khitam Saeed
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- Cement
- by Madhavan Natarajan
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- Fibers, Asbestos, Cement, Size

1Lecturer, Department of Building, University of Jos, Nigeria 2Lecturer, Department of Building, University of Jos, Nigeria... more

1Lecturer, Department of Building, University of Jos, Nigeria 2Lecturer, Department of Building, University of Jos, Nigeria ---------------------------------------------------------------------***--------------------------------------------------------------------Abstract – This research is aimed at determining the suitability of millet hush ash (MHA) as partial replacement of cement in the production of sandcrete blocks. This study examined the physical and chemical properties of locally sourced millet husk ash as a pozzolana. Mix ratio 1:6 (cement: sand) was used in this study for sandcrete block production. Cement was partially replaced with MHA in varying percentages of 0, 10, 20, 30 and 40% by weight. The blocks were molded and cured for 7, 14 and 28 days. The compressive strengths of the blocks were determined at 7, 14 and 28 days by crushing using compressive strength testing machine. The result of the chemical analysis of the locally sourced millet husk ash showed that it is...

- by solomon anowai
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- Environmental Engineering, Civil Engineering, Cement, husk

In this study, the strength development and lechability aspects of metal-contaminated soil treated with ordinary portland cement (OPC) were investigated. The soil was collected from a scrap metal yard within the outskirts of Kuala Lumpur,... more

- by Hilmi Mahmud
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- Southeast Asia, Malaysia, Leaching, Eurasia
- by CRISTIAN jimenez
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- Civil Engineering, Carbon Dioxide, Life Cycle Assessment, Building

This contribution investigates the effects of seawater and colloidal silica (NS) in the amounts of 1, 3 and 5 wt%, respectively, on the hydration, strength development and microstructural properties of Portland cement pastes. The data reveal that seawater has an accelerating effect on cement hydration and thus a significant contribution to early strength development was observed. The beneficial effect of seawater was reflected in an improvement in compressive strength for up to 14 days of hydration, while in the 28 days compressive strength values were comparable to that of cement pastes produced with demineralized water. The combination of seawater and NS significantly promotes cement hydration kinetics due to a synergistic effect, resulting in higher calcium hydroxide (CH) production. NS can thus react with the available CH through the pozzolanic reaction and produce more calcium silicate hydrate (C-S-H) gel. A noticeable improvement of strength development, as the result of the s...

- by mohamed abd elrahman
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- Materials Science, Cement, Portland cement

Concrete is a construction material composed of Cement, fine aggregate, coarse aggregate, and water with or without admixtures. The concrete industry is one of the heaviest consumers of natural resources due to which sustainability of concrete industry is under threat. The biggest problem facing the concrete industry is the environmental and economic concern. In this research Paper , the Ordinary Portland Cement (Grade 43) has been partially replaced by Waste Glass Powder (GLP) and in Second stage Natural sand and cement replaced by stone dust and waste glass powder accordingly in the proportion of 0%, 10%, 20%, 30%, 40% & 50%, at constant 15 % of Waste glass powder by weight of M-30 grade concrete. Concrete mixtures were produced, tested and compared in terms of Compressive Strength, Split Tensile Strength and Flexural Strength of the conventional concrete at a period of 28 days. It is observed that glass Powder and stone dust gives better results as compared to conventional concrete. It is found that strength and workability of mixes increases significantly when glass Powder and stone dust is used.

- by IJRASET Publication
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- Concrete, Compressive Strength, Cement, Strength of materials

The use of air entraining agents have been accepted practice in cement technology for many years. A large number of uniform and stable micro bubbles is intentionally entrained to improve the durability and reduce the potential for damage from freezing and thawing, but these bubbles are inversely affected the hardened cement paste compressive strength. The Physiochemical and Mechanical Properties of cement pastes containing synthetic nonionic surfactant Lauryl glucoside (LG) as air-entraining agents are investigated. Different cement pastes with and without LG are prepared for five interval times (3, 7, 28, 90 and 360 days).
The influence of the different surfactant concentrations on the air content of the pastes and accordingly the bulk density, compressive strength and microstructure of the hardened cement specimens is discussed. The optimal level of factors to achieve the desired goals are determined. The results show that LG causes a uniform distribution of small air voids in the cement paste, beside its ability to accelerate the hydration reaction, which may greatly improve the compressive strength of the pastes.

- by Alaa Musalam
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- Cement

Abstract Different weight ratios of microemulsion-based gelatin uniform microspheres (GMs) were added to the tetra calcium phosphate (TTCP)-based cement (CPC) to investigate the physical, mechanical and apatite-forming ability of the CPC. The GMs contained 20 wt% of glycidoxypropyltrimethoxysilane (EPPTMS) as a crosslinking agent. The average size of GMs was on the order of 35 μm. For CPC, the initial and final setting times were 10 min and 21 min, respectively. These values were prolonged up to 18 min and 28 min, respectively, for CPC containing 10 wt% of GM (CPC-10GM). The highest injectability percentage and injection time was related to the CPC-10GM. The highest mechanical values were related to CPC-5GM while CPC-10GM possessed the lowest compressive strength and Young's modulus. Apatite formation on the surfaces of all samples was confirmed by acellular in vitro bioactivity experiment after various periods of soaking time in simulated body fluid (SBF). Needle-like HA precipitates were manifested on the surface of CPC-5GM. According to MTT colorimetric assay, the viability rate of cells on the surfaces of CPC-5GM and CPC increases significantly with time. An appropriate attachment of G-292 cells on the surface of both samples after 48 h was observed by DAPI staining and SEM imaging methods. There was considerable difference in the ALP activity per cell basis between CPC and CPC-5GM at intervals of 7–21 days. These results indicate the potential of the CPC–5GM composites to be used in bone replacement.

- by Navid Ahmadi Nasab
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- Engineering, Materials Science, Calcium, Cement

Abstract The carbon dioxide (CO2), in the presence of water, forms a corrosive medium that reacts with the Portland cement hydrated products in a process denominated carbonation. Carbonation is a topic of great interest for the oil and gas industry due to deleterious and negative effects caused by formations that contain CO2 in their pores to the cements used in cementing operations, as primary and remedial cementing. The corrosive compound present in subsurface can be originated from geological processes, injection techniques for enhanced oil recovery and geological storage. This work evaluated characteristics of CO2 attack in class G Portland cement slurries formulated with different densities: 1890 kg/m3 (15.8 ppg), 1970 kg/m3 (16.5 ppg) and 2030 kg/m3 (17.0 ppg). The slurries were prepared, cured, and subsequently exposed to CO2 during periods of 30, 60 and 90 days in an autoclave with controlled temperature and pressure conditions. After the times inside the autoclave, the samples were analyzed with a pH indicator solution, sedimentation test and scanning electronic microscopy (SEM). The results showed an inversely proportional pattern: the higher the density, the lower the carbonation. The higher content of reactive solids contributed to make the matrix more closed and with a greater availability of hydrated cement products, acting as a barrier to the carbonation advancement.

- by Julio Cezar Freitas
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- Civil Engineering, Materials Science, Building, Cement

As interest in the exploration of Mars intensifies and advancements in technology increase the viability of just such a mission, one of the very first problems facing explorers, and eventually settlers, is adequate shelter. An extremely promising candidate material for the building of these structures is concrete made using Martian soil as the aggregate and Sulphur as the cement. This Martian Concrete is strong, and would be more durable in Mars' weaker gravity, more reusable than regular concrete, and significantly dense 1 , enough to provide a measure of protection from the radiation found on Mars' surface, which is moderately more pervasive than the radiation on Earth's surface. Building these structures by hand would be inefficient and costly, taking time away from other important and urgent activities. The advent and proliferation of 3D printing in Earth based architecture holds many possibilities for application off-world. Since 3D printing technology is advancing and often providing cheaper ways of building many different types of structures of virtually any design. By adapting and redesigning some of the plans and ideas presented for 3D printing structures on the Moon 2 and conceptualizing architecture that would be better suited for the Martian environment, it is possible to build adequate and lasting structures quickly and cheaply using materials found in abundance on the Martian surface. As numerous projects advancements in 3D printing in architecture and construction have demonstrated 3 , 3D printed structures are safe, sound, and easily made. Combining existing technology and Martian Concrete will be the best and most sustainable way to build habitats on Mars.

- by Jonathan Harline and +1
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- Structural Engineering, Planetary Science, Composite Materials and Structures, Mars
- by Harald Justnes
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- Civil Engineering, Cement

In the present study, an investigation was conducted to evaluation of tile, brick, fire brick, plaster and concrete wastes derived from construction and demolition (C&D) wastes in Portland cement raw meal production as secondary raw material. Clinker test results showed that using of these wastes in cement was suitable. Then, cement production was performed with using 1, 2.1 and 3.9 wt. % mix C&D waste addition ratios in the cement factory. Desired phases like belite and alite, which are essential for the cement products, were observed at the micrographs. Also, obtained cement products supplied required and standard properties; however, strength and hydration heat values were lower. Finally, optimum C&D waste addition ratio was determined and results were found as practicable. It was shown that mix C&D waste materials can be utilized as secondary raw material in cement production.

In the challenging quest for a solution to reduce the risk of implant-associated infections in bone substitution surgery, the use of silver ions is promising regarding its broad spectrum on planktonic, sessile as well as multiresistant bacteria. In view of controlling its delivery in situ at the desired dose, we investigated its encapsulation in carboxymethyl cellulose (CMC) microparticles by spray-drying and included the latter in the formulation of a self-setting calcium phosphate bone cement. We implemented an original step-by-step methodology starting from the in vitro study of the antibacterial properties and cytotoxicity of two silver salts of different solubility in aqueous medium and then in the cement to determine the range of silver loading able to confer anti-biofilm and non-cytotoxic properties to the biomaterial. A dose-dependent efficiency of silver was demonstrated on the main species involved in bone-implant infection (S. aureus and S. epidermidis). Loading silver in microspheres instead of loading it directly inside the cement permitted to avoid undesired silver-cement interactions during setting and led to a faster release of silver, i.e. to a higher dose released within the first days combining anti-biofilm activity and preserved cytocompatibility. In addition, a combined interest of the introduction of about 10% (w/w) silver-loaded CMC microspheres in the cement formulation was demonstrated leading to a fully injectable and highly porous (77%) cement, showing a compressive strength analogous to cancellous bone. This injectable silver-loaded biomimetic composite cement formulation constitutes a versatile bone substitute material with tunable drug delivery properties, able to fight against bone implant associated infection. STATEMENT OF SIGNIFICANCE: This study is based on two innovative scientific aspects regarding the literature: i) Choice of silver ions as antibacterial agent combined with their way of incorporation: Carboxymethylcellulose has never been tested into bone cement to control its drug loading and release properties. ii) Methodology to formulate an antibacterial and injectable bone cement: original and multidisciplinary step-by-step methodology to first define, through (micro)biological tests on two silver salts with different solubilities, the targeted range of silver dose to include in carboxymethylcellulose microspheres and, then optimization of silver-loaded microparticles processing to fulfil requirements (encapsulation efficiency and size). The obtained fully injectable composite controls the early delivery of active dose of silver (from 3h and over 2 weeks) able to fight against bone implant-associated infections.

- by Fabien Brouillet
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- Materials Science, Medicine, Multidisciplinary, Biofilm

This study aimed to determine the cement industry's impact on ambient air quality inside and around a Saudi Arabian cement plant. Air quality has assessed in terms of several indicators: carbon dioxide, carbon monoxide, nitrogen dioxide, sulfur dioxide, PM10, PM2.5, ozone, and volatile organic compounds. AERMOD model was used to predict the concentrations of pollutants in the surrounding area. Results obtained revealed that the concentration of all impurities is within the standard limits for ambient air quality. In comparison with OSHA guidelines, only PM10 concentration exceeded the allowable limit. The higher concentrations of pollutants are recorded at the site closest to the plant site (S1, a housing compound located 0.8km ESE from the plant). Concentrations at the other monitoring sites decreased significantly. Except for PM10, the calculated hazard quotient (HQ) of all pollutants was <1which indicated no health effects are expected. The HQ of emissions can be ranked as...

- by DR.Kamel ALZBOON
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- Environmental Science, Air Quality, Health, Cement

The present study involved the utilization of crushed glass as an auxiliary additive in the manufacture of cement stabilized fly ash (CSF) bricks. The bricks were made with 1:1 proportion of fly ash and sand stabilized with 20 % cement. Crushed glass was used as replacement for the fine aggregate in increments of 10 % up to 40 % wherein the sand was completely replaced with crushed glass. The various mix proportions were then moulded into bricks with the addition of water by hand moulding method of forming the bricks and sun dried followed by sprinkle curing over a period of 21 days. The bricks were then subjected to compressive strength, water absorption and efflorescence tests to gauge its performance. The investigation revealed that the addition of crushed glass to the brick mix resulted in an increase in strength of the bricks, however, the maximum strength achieved could not achieve the strength of the control specimen. But the strength was higher than the minimum strength recommended by Bureau of Indian Standards (BIS) for stabilized blocks as well as burnt bricks. It also reduced the water absorption marginally while no efflorescence was seen in any of the combinations. A cost comparison revealed that the optimal combination with crushed glass was able reduce the cost of the brick by 20 %.

- by Jijo James and +2
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- Waste Management, Cement, Flyash, Stabilized Compressed Earth Blocks
- by barrie dams
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- Materials Science, Cement, Composite Material

The aim of this work is to valorize a natural mineral source such as the pure limestone (P.Lime) of Bani Qais-Amran-Yemen, by introducing it in the production of cement to achieve the following objectives:  Minimize the emission of CO 2 into the atmosphere which is the main cause of the greenhouse effect;  Develop a new durable hydraulic Binder;  Improve physical-chemical of cements as well as the mechanical performance of concrete;  Gain a percentage of energy and raw materials consumed. We have prepared the new durable cements from the clinker and the P.Lime. Partially substituting the clinker by this natural material in powder form which was finely at different percentages ranging from 0 to 40% by weight of the clinker with a pitch of 5%. The influence of the incorporation of the P.Lime in cement on the physical-chemical characteristics of cement such as the specific surface area, the density was studied. The effect of addition of P.Lime in cement on the physical properties of fresh cement paste was also studied to know the setting time and the water content. Also, the influence of the addition of the P.Lime on the compressive strength of mechanical of cement at hardened state has been studied.The obtained results by the different physical-chemical analysis showed that the addition of P.Lime in cement increased the fineness by the specific surface. In more, the density decreases. We have remarked that, the setting time decreases when the percentage of the P.Lime is increased. Of the same, the compressive strengths of mechanical at 2, 7 and 28 days have improved with the increase the amount of P.Lime.

- by Mohammed Khudhair and +2
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- Cement, Limestone, Pozzolans, Cement Based Composites

Ordinary Portland Cement is recognized as a major construction material throughout the world. Researchers all over the world today are focusing on ways of utilizing either industrial or agricultural waste, as a source of raw materials for industry. This waste utilization would not only be economical, but may also result in foreign exchange earnings and environmental pollution. wastes, such as blast furnace slag, fly ash and silica fume are being used as supplementary cement replacement materials. A few studies have been carried out on the ashes obtained directly from the industries to study pozzolanic activity and their suitability as binders, partially replacing cement. This project analyses the effect of SCBA in concrete by partial replacement of cement at the ratio of 0%, 5%, 10%, 15% and 20% by weight by using magnesium sulphate solution. The bagasse is an important by-product of the sugar cane industry and most of it is used to produce steam and electricity in a co-generation plant at the ethanol plant.. This experimental study examines the compressive strength of concrete. The main ingredients used are Portland cement, SCBA, river sand, coarse aggregate and water. After mixing, concrete specimens were casted and subsequently all test specimens were cured in water at 7 days, 28days, 56days, 90days, and 180days.

The objective of this paper is to evaluate the effect of silica aerogel on the thermal conductivity of cement paste for the construction of concrete buildings in sustainable cities. Samples consisting of Ordinary Portland Cement (OPC), free water and different volumes of silica aerogel were prepared and cured for three (3), seven (7) and 28 days. Compressive strength tests were performed on samples at three (3), seven (7) and 28 days of curing. Porosity and thermal conductivity tests were conducted on samples at 28 days of curing. The lowest thermal conductivity measured was 0.076 W/mK, which was achieved by sample mix with 20 ml of silica aerogel (M20), which represents a 93.58% reduction in thermal conductivity relative to the control mix. The highest permeable porosity measured for cement paste incorporated with silica aerogel was 25.6%, which was also obtained by sample M20. However, the highest compressive strength measured was 54.33 MPa, which was obtained by sample mix with 10 ml of silica aerogel (M10) at 28 days of curing. The addition of silica aerogel as filler in cement paste can reduce the thermal conductivity of cement paste at the expense of reduced compressive strength and increased permeable porosity.

- by Nadzhratul Husna
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- Concrete, Compressive Strength, Cement, Thermal Conductivity
- by Selim Yücel
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- Cement, Cimento, Cüruf, Yüksek Fırın Cüruf

The paper presents the results of the studies performed on the influence of redispersible powders and of the cellulose ethers in mineral plasters applied as the last layer in exterior thermal insulation composite systems. Starting from traditional recipes, using polymeric additives specific for ETICS, there were developed original products in which the polymer additive (redispersible powder) concentration was modified with impact on physical and mechanical characteristics. The using of the cellulose ether led to obtaining some light compositions (smaller density) and good workability at application. The using of the redispersible powders has contributed to obtaining some mortars with low water permeability, high water vapour permeability and good support adherence, significant advantages for the products durability. There have been highlighted the chemical interactions between the redispersible powders and the Ca 2+ ions released during the cement hydration process. The redispersible powders act as a second binder in the system, thus leading to improved performance. În prezenta lucrare a fost studiată influenţa pulberilor redispersabile şi a eterilor de celuloză în tencuielile minerale aplicate ca ultim strat în sisteme de izolare termică la exterior. Pornind de la reţete tradiţionale, utilizând aditivi polimerici specifici pentru sistemele ETICS au fost concepute produse originale în care s-a modificat concentraţia de aditiv polimeric (pulbere redispersabilă) cu impact asupra caracteristicilor fizico-mecanice. Utilizarea eterului de celuloză a condus la obţinerea unor compoziţii uşoare (densitate mai mică) şi lucrabilitate bună la aplicare. Utilizarea pulberilor redispersabile a contibuit la obţinerea unor mortare cu permeabilitate la apă scăzută, permeabiltate mare la vapori şi aderenţă bună la suport, avantaje semnificative pentru durabilitatea produselor. Au fost puse în evidenţă interacţiuni chimice între pulberile redispersabile şi ionii de Ca 2+ eliberaţi la procesul de hidratare a cimentului. Pulberile redispersabile acţionează ca un al 2-lea liant în sistem conducând astfel la performanţe îmbunătăţite.

- by DANIELA FIAT
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- Polymers, Cellulose, Cement, mineral plaster
- by Mehdi Bakhshi
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- Chemical Engineering, Civil Engineering, Convection, Mass Transfer
- by Selim Yücel
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- Cement, Beton, Cement and Concrete Materials, Beton Standardları

“Đại dịch Covid-19 đặt ra thách thức lớn đối với ngành xi măng VIệt Nam. Không chỉ là sự kiện làm gián đoạn tới các hoạt động của ngành trong một tháng hoặc quý, dịch Covid-19 còn tác động trực tiếp đến quá trình thoái trào về nhu cầu tiêu thụ xi măng đã diễn ra trong nhiều năm trở lại đây. Điều này đồng nghĩa với việc, tiêu thụ xi măng trên các thị trường hiện tại sẽ có thể giảm sâu trong năm 2020, đặt áp lực lên khả năng cạnh tranh và duy trì hoạt động của các doanh nghiệp xi măng Việt Nam trong thời gian tới.”

- by Mehran Khan
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- Civil Engineering, Materials Science, Fiber, Building
- by Ankit Jhamb
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- Civil Engineering, Architecture, Cement, Ceramic Dust

The Cost as well as the time taken by the construction work has always attracted attention of Civil Engineers to be supplemented by some cheaper and fast settling construction material. This paper focuses the advantages of using Concrete canvas or Concrete cloth for Rapid and fast construction of structures like canals and many other which are made for temporary purpose. In the paper the engineering properties of the material is also discussed. This material being ceramic is fire resistant as well as water proof.

The use of cement and concrete is becoming increasingly widespread all over the world. However, the high energy consumption required for the production of clinker and the greenhouse gas emissions generated during production negatively affect both the economy and the environment. In the studies conducted for many years, researchers have found that the substitution of various pozzolans with cement provides both technical advantages and environmental benefits. The use of pozzolans in cementitious composites provides advantages such as the improvement of the physical and mechanical properties of the material, the conservation of the environment and the economy in terms of the evaluation of industrial wastes. In recent years, studies on the use of nanoparticles in cementitious composites are positively. In this study, it was aimed to investigate the properties of fresh and hardened cement mortars using micro silica as pozzolan and nano silica as nanoparticle. For this purpose, four different cement pastes and mortars mixtures were prepared by substituting 0%, 1%, 2%, 3% nano SiO2 (silica) cement in mortar mixtures containing 5% micro silica. The effects of the nano silica on the micro silica-containing cement paste on the consistency and setting time were investigated. The mortar mixtures produced were subjected to flexural and compressive strength tests on days 7, 28 and 90 th. SEM images of mortar mixtures were taken. As a result, it was found that 2% nano silica ad-mixture of 5% micro silica containing cement admixture affects the flexural and com-pressive strength positively, whereas 2% nano silica admixture increased the flex-ural strength by 13% and compressive strength by 7%.

- by Ilknur Bekem
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- Concrete Technology, Durability of Concrete, Cement, Cement and Concrete Materials

An exhaustive study of available literature on use of activated carbon in cement
composites was done. Adsorptive nature of activated carbon can be effectively used to
remove toxic air pollutants such as nitrogen oxide, volatile organic compounds by
adsorbing to concrete elements (chimneys, tunnels etc.). Experimental research work
carried out on cement composites containing activated carbon revealed its potential
ability to improve physical, mechanical and durability properties of cement
composites. A comprehensive review of selected literature was carried out and the
significant findings are presented in this paper. Researchers across the globe had
experimentally showed that presence of activated carbon at 1 to 4% in cement
composites positively influence various properties of cement composites.

- by IAEME Publication
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- Concrete, Adsorption, Activated Carbon, Compressive Strength
- by yamusa bello
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- Environmental Engineering, Civil Engineering, Cement, Cation

Cilt/Volume : 7 Sayı/Number: 2 Yıl/Year: 2018 Sayı/Pages: 75-85 Alınış tarihi (Received): 09.02.2018 ÖZET: Bu çalışmada Artvin-Borçka'da bulunan Muratlı çay fabrikasına ait yakma ünitesi kuru tip toz siklon filtre sisteminde tutulan kömür külünün endüstriyel bir atık olarak beton üretiminde kullanılabilirliği araştırılmıştır. Farklı oranlarda çimentoya ikame edilmiş kömür külü atığının betonun taze ve sertleşmiş özelliklerine etkisinin belirlenmesi amaçlanmıştır. Bu amaca yönelik olarak, %0, %5, %10 ve %15 oranlarında kömür külü atık olarak çimento ikamesi ile C20/25 sınıfı 4 farklı beton karışımı hazırlanmıştır. Taze beton üzerinde slump deneyi, sertleşmiş beton örnekleri üzerinde ise Schmidt çekici, ultrases geçiş hızı ve basınç dayanımı testleri yapılmıştır. Çalışma sonunda erken yaşta (7. Gün) %5 atık ikamesinin referans betona göre ultrases geçiş hızını (%3.40) ve basınç dayanımını (%19.70) arttırdığı; 28. günde ise atık malzemenin C20/25 tasarımında beton içerisinde çimento ikamesi ile % 15'e kadar kullanılabileceği görülmüştür. Anahtar Kelimeler: Beton, endüstriyel atık, çay fabrikası, kömür külü. ABSTRACT: In this study, the possibility of using coal ash which held in dry powder cyclone filter system in combustion unit of Muratli tea factory in Artvin-Borcka, in concrete production has been researched. It is aimed to determine fresh and hardened concrete properties of cement substituted waste coal ash added concrete at different ratios. For this goal, four different concrete mixes of C20/25 class substituted with 0%, 5%, 10% and 15% dust is prepared. Slump experiment on fresh concrete, on the hardened concrete specimens, Schmidt hammer, ultrasound transit speed and compressive strength tests were carried out. At an early age (on 7th day), 5% waste residues increase the ultrasonic pulse velocity (3.40%) and compressive strength (19.70%) compared to the reference concrete; On the 28th day, it is seen that waste material can be used up to 15% with cement substitution in concrete in C20 / 25 design.

- by Ilknur Bekem
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- Concrete, Waste Management, Concrete Technology, Cement
- by SERENA MARCHI
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- Architectural History, Cement, Cement Industry, Il Riuso Di Edifici Abbandonati

Thermal activation of Ga’ara kaolin is used to produce a good quality metakaolin. Portland cement clinker is ground
and blended with 3% gypsum. In this study, two types of mixes are made: the first using 10% hydrated lime and
different percentages of metakaolin as replacement by weight of the blended cement; in the second type, only
metakaolin is used, without hydrated lime, in mixes as a replacement by weight of the blended cement. The aim of
this study is to make a new type of environmentally friendly, blended cement with good fresh and hardened
properties. Energy savings can be achieved by using materials produced as industrial by-products (metakaolin,
hydrated lime). The compressive strength is 42.1 MPa for the mix with 12% metakaolin and 0% hydrated lime, and
38.8 MPa for 12% metakaolin with 10% hydrated lime, as compared to the reference mix value of 37.9 MPa at age
90 d. Blended cement can be made with 86% Portland cement fineness, adding 22% metakaolin + hydrated lime as a
replacement by weight of the blend, to give almost the same compressive strength as the reference mix, with
excellent soundness properties. This could reduce the annual production of cement, as well as the associated
emission of gaseous pollutants from factories during the cement production process.

Avec l’évolution technologique et démographique de l’homme et son besoin vital des zones arides et semi arides, il envahit le désert pour exploiter ses richesses, ce qui conduit à une présence des eaux plus importante qu’avant ; que ce soit pour les besoins agraires ou pour les besoins industriels. La présence des eaux dans ces régions favorise la création de l’environnement idéal pour l’effondrement des sols et, par conséquent, la ruine des constructions. Ceci nous oblige à proposer des solutions de traitement économique et faciles à mettre en œuvre. Cette étude expérimentale présente le cas de traitement par le ciment d’un sol affaissable, reconstitué au laboratoire, en utilisant la méthode double consolidation. Les résultats obtenus montrent qu’il est possible de diminuer le potentiel d’affaissement de ce sol à un niveau acceptable par l’ajout d’une faible teneur en ciment avec différentes teneurs en eau initiales et sous l’effet de plusieurs énergies de compactage.

- by Azzeddine LAHMADI
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- Collapsible Soils, Unsaturated Soils, Cement, Soil Treatment

This paper aims to provide background information on raw materials included in the cement industry that have chemically examined. The raw materials entering the factory examined, which include stone, crude oil, iron dust, sand, and gypsum, as it found that the total carbonate ratio is 89 percent as a weight ratio and the sulfide is smaller or equal to 1 percent as a weight ratio, and the magnesium carbonate is smaller or equal to 3 percent. For iron dust with sand, the total carbonates of the mixture were smaller or equal to 85 percent, and magnesium carbonate was smaller or equal to 3 percent. Silica oxide also examined in the sand were the results of the examination were greater than 85 percent. For sulfide oxide smaller than 1 percent, as well as for iron dust, the proportion of oxide Ferric is higher than 55 percent, the percentage of alumina oxide is less than 10 percent, silica oxide is less than 20 percent, as well as for crude oil, as it contains less than 4 percent of sulfide oxide, as well as primary and secondary gypsum examination, and it found that sulfide oxide is greater than 31 percent if the gypsum is Secondary and greater than 42 percent if the gypsum is primary. Materials are non-soluble smaller than 8 percent if it was secondary gypsum and less than 5 percent if the primary gypsum. Where these models examined and analyzed, and the storage location of the models examined were determined.

- by Jameel Tawfiq
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- Materials Engineering, Cement, University of Kufa
- by Eric E Hiatt
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- Geology, Geochemistry, Sedimentology, Diagenesis

Concrete with bottom ash and fly ash added as replacement for sand and cement, respectively. Compressive, flexural and tensile strengths of the concrete are determined. Pulse velocity, drying shrinkage and micro-structural tests are performed. Relationship between mechanical properties and pulse velocity is discussed. a b s t r a c t Malaysia produces about 8.5 million tons of coal ash as waste which comprises of bottom ash and fly ash. Reusing such waste which is otherwise sent to landfills is an environment-friendly option. Hence, the major aim of this research study was to investigate their use in concrete to replace sand with bottom ash waste and cement with fly ash. Concrete specimens were prepared incorporating 0, 20, 50, 75 and 100% of bottom ash replacing sand and 20% of coal fly ash by mass, as a substitute for Ordinary Portland cement. Fresh and hardened state properties of the experimental specimens were determined. Results revealed that concrete workability reduced when bottom ash content increased replacing sand. On the other hand, at the early age of 28 d, no significant effect was observed in compressive, flexural and tensile strengths of all concrete samples. After curing at 91 and 180 d ages, compressive strength of both the experimental and control concrete samples increased significantly but remained almost similar. However, flexural and splitting tensile strengths of the experimental mix containing 75% bottom ash and 20% fly ash exceeded much more than the control sample. Moreover, drying-shrinkage of experimental concrete mixtures containing 50%, 75% and 100% bottom ash and 20% fly ash was lower than the control mix. It is concluded that those experimental concrete mixes can be used in several structures (foundations, sub-bases, pavements, etc.) which will minimize the cost, energy and environmental problems to a great extent.

- by Mahdi Rafieizonooz and +2
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- Concrete, Cement, Coal Fly Ash, Coal Bottom Ash
- by ryan rd
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- Cement, Cement Industry, Cement and Concrete Materials

Advancement in Medical field is an active part of development in science and technology. With the continuous increase in population and increase in use of medical facilities there is sharp rise in generation of medical waste. These wastes are hazardous in nature and have the greatest potential to have impact on living being and environment. One of the important methods of treatment of such waste is incineration but this method also produces ash which is a subject of land filling. This causes wastage of large area of land also leaching of contaminants in ashes cause contamination of ground water. The purpose of this project is to find some alternative for land filling of incineration ashes.

- by Dr. Napoleon Usman
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- Civil Engineering, Concrete, Cement, Sawdust

Code: (ASTM C191) 2.1 Purpose The purpose of this test is to determine the initial and final setting time of hydraulic cement by Vicat needle apparatus. 2.2 Significance and Use 1) According to weather we define setting... more

Code: (ASTM C191)
2.1 Purpose
The purpose of this test is to determine the initial and final setting time of hydraulic cement by Vicat needle apparatus.
2.2 Significance and Use

According to weather we define setting time by adding retarder or accelerator.
We arrange the formwork according to setting time.
It is helpful in deciding the mixing time duration of concrete.
The knowledge of setting time is helpful in deciding the time to transport, place and compact the concrete effectively.

- by jahanzaib ch
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- Concrete, Reinforced Concrete Structures, Cement

Leaving the waste materials to the environment directly can cause environmental problem. Hence the reuse of waste material has been emphasized. Waste can be used to produce new products or can be used as admixtures so that natural resources are used more efficiently and the environment is protected from waste deposits. Marble stone industry generates both solid wastes and stone slurry. This paper focus on the utilization of waste of Marble dust powder in concrete and enhancement of strength of concrete more economically. The Marble dust powder was added in M20 grade of concrete at (0%, 5%, 10%, 15%, 20%, 25% & 30%) with partial replacement by weight of cement. Water/Cement ratio (0.50) was kept constant, in all the concrete mixes. The concrete samples (cube & cylinder) were tested for compressive strength and split tensile strength after 7 & 28 days of proper curing. The results of the laboratory work showed that replacement of cement with Marble dust powder increases up to 10% for both compressive strength and split tensile strength of concrete.

This work compares a range of limestone extended cements, classifies each blend according to their respective cement specifications, and assesses the effect of the limestone on the strength development, water demand and plastic properties in concrete with a given target strength of 38MPa. Furthermore, the interaction that limestone has in the hydration process is evaluated.
The scope of this experiment is to determine the maximum level of limestone in a given mix before it starts to negatively affect the performance of the concrete whilst comparing the benefits in CO2 emission savings per ton of cement and translating this to an effective CO2 contribution per cubic meter of concrete.