Addition Of Cement Research Articles

Impact of Cement Additives on Capillary Pressure and Petrophysical Properties in Oil Well Cementation for Geological Hydrogen Storage

Impact of Cement Additives on Capillary Pressure and Petrophysical Properties in Oil Well Cementation for Geological Hydrogen Storage

Improvement of vibration response of a foundation resting on Salt-Encrusted Flat Soil by cement addition: a numerical investigation

ABSTRACT Excessive vibrations can negatively impact machinery performance by causing misalignment, decreased accuracy, increased wear and tear, and reduced overall operational efficiency. By conducting a numerical investigation on improving vibration response through cement addition to salt-encrusted flat soil, the study aims to enhance the performance and reliability of machine foundations, thereby optimizing machinery operation. The properties of untreated sabkha and cement-sabkha were calibrated to use in the Finite Element Method (FEM) model. The variables investigated have the thickness of cemented sabkha ratio, operation frequency, three types of subsoils (Sabkha and cemented sabkha of 5% and 10%), and vertical amplitude loading. The main findings revealed that the maximum shear modulus (Gmax) increases by 47% with a 5% to 10% increase in cement content. In addition, as the vibration’s frequency increases, the amplitude displacement is observed because the reflected waves become smaller for the foundation resting on cemented sabkha. The natural frequency rises as the thickness ratio and cement amount of cemented sabkha increase. The influence of the thickness ratio on displacement amplitude is considerable when the operation frequency is less than 20 hz. The study implies that engineers can optimize the design of machine foundations to achieve better performance and stability.

Poly(carboxylated ether)s as Cement Additives: The Effect of the Addition Method on Hydration Kinetics.

Polycarboxylate ether (PCE) superplasticisers have been widely used in cement formulations. However, it is not until recently that several studies have analysed the relationship between the properties and the molecular structure. In the present work, PCEs with different side chain lengths and charge densities synthesised through free radical copolymerisation are used to analyse the effect they have on the hydration of ordinary Portland cement (OPC). It was found that the addition method of these PCEs to the OPC significantly affects the hydration kinetics of the cement paste. When PCEs are added through the direct addition method, a linear dependency between the retardation of hydration and the microstructure of the used PCEs is observed. On the contrary, when PCEs are added through the delayed addition method (PCEs are added to the cement paste 5 min after water), no retardation in hydration is observed, but the rate of hydration is reduced.

Experimental Study on the Effect of Calcium Aluminate Cement Addition on the Drying and Physical Properties of Refractory Castables Containing Colloidal Silica.

Colloidal silica-bonded castables offer several advantages compared to traditional calcium aluminate cement (CAC)-bonded castables, including lower torque values during mixing, superior drying properties, and a lower CaO content. Nevertheless, information on the combination of CAC and colloidal silica is limited, and the effect of CAC additions on the drying properties of colloidal silica-bonded castables remains unknown. In this study, these drying properties were measured by rapidly heating 400 kg samples to 500 °C and assessing the resulting damage to each sample. Additionally, the physical and chemical properties of small-scale samples were analyzed to evaluate the impact of CAC addition. The analyzed properties included cold crushing strength (CCS), density, permanent linear change (PLC) and weight loss. The microstructure of the samples was investigated by FESEM and EDS. The results indicate that adding 1.5 wt.% increased the cold crushing strength at 20 °C, while lower CAC amounts had no noticeable effect. A mullite phase was observed in the sample without CAC, and correspondingly, anorthite was found in those with CAC additions. The samples exhibited significant differences in the drying tests, with the degrees of damage increasing with the CAC addition.

Seaweed waste in eco-friendly construction materials: Valorization of Sargassum ash as a mineral addition in fiber cements

Many coastal regions have recently faced significant challenges due to the excessive accumulation of sargassum. This genus of brown marine algae generates greenhouse gases such as methane and carbon dioxide during decomposition, as well as toxic gases such as hydrogen sulfide and ammonia. The substantial influx of these algae on shores brings far-reaching impacts on the environment, climate, health, and the economy. One way to mitigate these impacts is by using this biomass for energy production and applying the resulting ash as an alternative material in the construction industry. As such, this study aims to analyze the feasibility of sargassum ash as a replacement for limestone in fiber cement. This not only offers an environmentally responsible solution for its disposal, but also adds economic value to a material commonly seen as a waste. Several analyses were conducted on the physical and mechanical properties of fiber cement with varying percentages of limestone replaced by sargassum ash (0, 25, 50, 75, and 100 %), as well as its durability and Life Cycle Assessment (LCA). The fiber cement with 100 % sargassum ash exhibited a 74 % increase in specific energy compared to the fiber cement without the ash after accelerated aging. This mix design also presented better environmental performance in 15 of the 18 impact categories. The results demonstrate that ash holds potential as an alternative material in fiber cement manufacturing.

The impact of calcined mud on the rheological properties of eco-friendly concretes using the equivalent mortar method (CEM)

In order to harmonise technical and environmental aspects, people today focus not only on concrete's technical characteristics but also on environmental imperatives. Thus, the emphasis is on the development of concrete and cements that offer ecological and sustainable advantages. Commonly, people use various natural materials as cement additives, demonstrating their effectiveness by replacing a significant portion of the cement in the hardened state of concrete. This substitution leads to a substantial and remarkable reduction in carbon dioxide emissions. However, when it comes to the physical properties of the material in its fresh state, challenges may arise. Indeed, the rheological changes induced by these additives may hinder the on-site use of this eco-concrete. The main purpose of this study is to find out how adding minerals to environmentally friendly concrete changes its rheological parameters (yield stress, plastic viscosity) and fresh properties (slump, flow time). We will approach this using the concept of mortar equivalent to concrete (CEM). We developed five formulations of CEM’s by substituting cement with calcined mud (CM) in binary mixing systems at a temperature of 20 °C. The results showed that adding binary cements with calcined mud had a negative effect on the fresh properties and rheological parameters. However, when substitution happens at a low rate, it behaves almost like control mortar (OPC).

Assessing the life cycle and economic impact of cement-modified biochar compared to conventional adsorbents for heavy metal removal in stormwater

Modified biochar is used for heavy metal removal from stormwater, but current modifications rely on high-cost chemicals and result in highly toxic effluents. Additionally, there is limited research on these modifications' environmental impact and cost. This study aims to investigate the life cycle analysis (LCA) and economics of the process of absorption of Cu, Pb and Zn from synthetic stormwater utilizing cement-modified biochar adsorbent and compared it with commonly available adsorbents, activated carbon and zeolite. The cradle-to-gate LCA used experimental data and the Ecoinvent 3.0 database. Adding 1.5 % cement to biochar reduced its negative environmental impact by two to three times compared to plain biochar. Cement addition enhances heavy metal removal by raising pH, promoting precipitation, and reducing metal mobility. Combined with biochar, it increases the available surface area for adsorption, further boosting the system's efficiency in contaminant removal. The cement-modified biochar had the lowest global warming potential (kg CO2 eq), about half of Paddy Husk Biochar (PHBC). Approximately 50–90 % of the environmental impact of cement-modified biochar, zeolite, and PHBC was attributed to raw material collection. The Saw Dust Biochar (SDBC) had the highest sensitivity towards transportation distances among the adsorbents considered. Due to its heightened adsorption capacity, the 98.5 % PHBC composite demonstrated the lowest environmental impacts for Cu and Zn removal in multi-metal systems. Transportation of raw materials and labor costs were the primary cost drivers for biochar-based adsorbents. Among the adsorbents, 98.5 % PHBC was the best, being cost-effective and efficient for heavy metal removal. It is suitable for at-source pollutant removal in low-rainfall and high-pollution areas. Overall, this study helped identify performance weaknesses and modification opportunities for cement modification of biochar in heavy metal pollution control.

Effects of seawater on properties of bentonite cut-off walls with/without cement addition

Bentonite-based cut-off walls have been widely used to protect coastal areas against seawater intrusion. However, salts contained in coastal soils affect the properties of bentonite cut-off walls, and the interactions between seawater and bentonite minerals with or without cement remain unclear. The aim of this study was therefore to evaluate the effects of seawater on the workability, strength and permeability of bentonite-based mixtures, prepared using three types of bentonite (sodium, calcium and seawater bentonite). The underlying mechanisms were further investigated through Atterberg limits, mineralogical and microstructural analyses. The results showed that cation exchange between seawater and bentonite leads to alterations in montmorillonite type and particle arrangement. This leads to a significantly reduced liquid limit and a slightly decreased plastic limit of bentonite, therefore narrowing the range of workable water content for bentonite–sand mixtures. Compared with sodium/calcium bentonite, seawater bentonite was less impacted by seawater, but showed a larger increment in workability after cement addition due to palygorskite dissolution. Under similar workability, the bentonite–sand–cement mixture with calcium bentonite yielded the highest strength and the lowest permeability. These findings illustrate correlations between bentonite mineral alterations and the properties of bentonite–sand mixtures with or without cement, and offer guidance for the construction of cut-off walls in coastal regions.

Effect of adding dune sand to tuff in Saharan road construction

The south region of Algeria is characterized by a wide surface, a scattered population and a very small ratio of road length per habitant. To allow the development of agricultural, industrial and touristic activities between different cities in the south of Algeria, it is necessary to maintain and to develop the road infrastructure. However the development of these infrastructures necessitates the use of huge amount of certified aggregates from quarries which is not available in the vicinity of the need. For these raisons, in the framework of sustainable development, a strategy which consists in using local materials like fine sediments (dune sand) and other types of material is engaged. The materials constituting the road layers, until today, have been limited to certain so-called noble materials (gravel, aggregates, etc.), but these are being depleted as a result of the intensive exploitation and the scarcity of quality careers. Gypso-limestone encrustation tuffs, the most used materials in pavements (base course and base course) in the Saharan areas such as southern Algeria, have shown acceptable behavior for many years until these last days, when this type of material begins to present certain limits under the effect of the intensity of the traffic. In order to promote the abundant wind sands in these regions, we are interested in developing the dune sands in the pavement as a mixture with the tuffs. The present work presents a contribution to the study of the behavior of the tuff of the Adrar region (South of Algeria) alone and mixed with the sand dunes in different formulations. The aim is to evaluate the evolution of mechanical properties including resistance to simple compression, the ability to compaction and punching (RBC). The work also discusses the influence of the addition of cement in low levels on the performance of the mixture.

The influence of residual asphalt material in the mechanical behaviour of soil-RAP mixtures for use in paving

ABSTRACT The evaluation of Reclaimed Asphalt Pavement (RAP)’s suitability for pavement layers, optimises resource use, reduces environmental impact, and supports cost-effective practices. In this sense this study aimed to characterise soil-RAP mixtures to ensure they meet the quality standards required for pavement applications. The study examined two types of soil mixtures: one soil-RAP aggregates and the other soil-virgin aggregates (VAM) to understand the impact of residual asphalt binder on aggregate particles. Various mass contents (30%, 50%, 70%, and 90%) were tested alongside conventional soil-gravel mixtures with equivalent proportions and gradation of RAP and VAM. Additionally, the study investigated the effect of adding 2% cement on the performance of both recycled soil-RAP mixtures and conventional soil-gravel mixtures. The analysis includes granulometry, Atterberg Limits, MCT (Miniature, Compacted, Tropical) classification, soil chemical characterisation and microscopic images, compaction in Modified Proctor Energy, CBR, Resilient Modulus tests and stress–strain analysis. The results have revealed that the residual asphalt binder, surrounding RAP aggregates, has reduced the soil mixtures’ strength for different RAP contents. However, the study demonstrated that the addition of cement rendered the soil-RAP mixture feasible, enabling the application of the studied mixtures of RAP to constitute subbase and base layers.

The Coordination of Aluminum Sulfate with a Water-Soluble Block Copolymer Containing Carboxyl, Amide, Sulfonic and Anhydride Groups Providing Both Accelerating and Hardening Effects in Cement Setting

Two water-soluble block copolymers composed of acrylic acid (AA), 2-acrylamido-2-methylpropane sulfonic acid (AMPS), and optionally maleic anhydride (MAH) were synthesized through ammonium persulfate-catalyzed free radical polymerization in water. The introduction of aluminum sulfate (AS) into the resulting mixtures significantly reduced the setting times of the paste and enhanced the mechanical strength of the mortar compared to both the additive-free control and experiments facilitated solely by pure AS. This improvement was primarily attributed to the inhibition of rapid Al3+ hydrolysis, which was achieved through coordination of the synthesized block copolymers, along with the formation of newly identified hydrolytic intermediates. Notably, the ternary copolymer (AA–AMPS–MAH) exhibited superior performance compared to that of the binary copolymer (AA–AMPS). In the early stages of cement setting, clusters of ettringite (AFt) were found to be immobilized over newly detected linkage phases, including unusual calcium silicate hydrate and epistilbite. In contrast to the well-documented role of polymers in retarding cement hydration, this study presents a novel approach by providing both accelerating and hardening agents for cement setting, which has significant implications for the future design of cement additives.

Cemented sand under hollow cylinder multiaxial loading

Improvement of granular soils mechanical properties can be achieved by the addition of bonding agents. In this research, low amount of Portland cement was added to a sand and its beneficial shear strengthening effects were evaluated under a range of multiaxial stress paths. The influence of the orientation of the principal axes of stress and strain on the stress-strain response and failure of cemented sand has only been scarcely investigated. Therefore, this experimental investigation reports the results of a series of consolidated drained hollow cylinder torsional tests with constant principal stress path direction, ασ, varying from 0° to 90° Results were compared with the shear behaviour of the uncemented sand tested under similar loading conditions. Results show that the addition of cement to the sand matrix increases the soil strength for all multiaxial stress path directions. The suitability of two multiaxial strength criteria for reproducing the shape of the failure envelope as a function of the orientation of principal stress axis ασ has also been analysed.

Treatment of Marine Clay Strength Behavior by Demolished Tile Materials and Cement

Known as a problematic soil in the civil engineering field, a sustainable solution to marine clay soil strength behaviour is needed. Another major concern in the engineering field is the solid waste management. Demolished Tile Material (DTM) is one of the largest contributors to construction waste. By utilizing DTM as a stabilizer product to treat marine clay soil, both problems can be minimized. The primary objective of this study is to assess the improvement in marine clay soil's strength characteristics through the addition of DTM and cement. Various proportions of DTM (4%, 8%, 12%, 16%, and 20%) were incorporated into the soil, with a constant 10% cement content. Unconfined Compressive Strength (UCS) measurements were taken at different curing times (0, 7, 14, 28, and 60 days). Results indicate a significant increase in UCS after treating marine clay with DTM and cement, with the most substantial improvement observed at 16% DTM content. The study also emphasizes the role of curing time in enhancing soil strength. The research findings shows that the potential of repurposing DTM for soil stabilization, reducing construction waste, and promoting environmentally responsible construction practices. This study also contributes to the sustainable development of marine clay areas in Malaysia and offers valuable insights for soil engineering and waste management in construction projects.

Influence of the Addition of Palm Kernel Shell and Ash on Concrete Performances: Study of Correlations between Intrinsic Material Properties

Sustainable development objectives in the construction sector is currently hampered by the high cost of materials (cement, aggregates) and the environmental impact of waste in some developing countries. The obtained results in this work on the influence of ash (PKSA) and palm kernel shell (PKS) used as a partial addition of cement and aggregates in concrete composition, enable their valorization as local materials to manufacturing the lightweight concrete with low-cost. This is an interesting contribution to the development of sustainable construction and environmental protection. The used palm kernel shells are produced in the palm oil industry in Republic of Congo. The highest values for density Cd(2348kg/m3), compressive strength Cs(27MPa) and splitting tensile strength Ts(2.4MPa) for concrete using PKSA were obtained at 2.5%. Those for concrete using PKS were obtained at 5 %, i.e. Cd(2165kg/m3), Cs(22MPa) and Ts(1.90MPa). the increase in concrete properties with PKSA compared to PKS is explained by the pozzolanic reaction of the palm kernel ash, which acts as a hydraulic binder. Correlations between fundamental concrete properties reliably describe the influence of PKS and PKSA, with a coefficient of determination R2 (0.9) superior at 0.5; the obtained mathematical models to prediction the concrete properties are a significant contribution for engineers. PKS is a concrete plasticizer, PKSA is a concrete setting and hardening accelerator. The production of low-carbon concrete with PKSA addition is a major step forward for the concrete industry.

Enhancing marl soil stability: nanosilica’s role in mitigating ettringite formation

Marl soil is highly prone to erosion when exposed to water flow, posing a potential threat to structural stability. The common practice of stabilizing soil involves the addition of cement and lime. However, persistent reports of severe ruptures in many stabilized soils, even after extended periods, have raised concerns. In stabilized marls, unexpected ruptures primarily result from the formation of ettringite, which gradually damages the soil structure. This article aims to assess the impact of nanosilica on the formation of ettringite and the nanostructure of calcium silicate hydrate (C-S-H) during the marl soil stabilization process with lime. To achieve this, marl soil was stabilized with varying percentages of lime and nanosilica. X-ray diffraction (XRD) patterns and scanning electron microscopy (SEM) images were collected to observe changes in mineralogy and microstructural properties. Various geotechnical parameters, including granularity, Atterberg limits, compressive strength, and pH, were measured. The results indicate that the uniform distribution of nanosilica in marl-lime soils enhances pozzolanic activities, calcium aluminate hydrate growth (C-A-H), and the nanostructure of calcium silicate hydrate (C-S-H). According to XRD and SEM experiments, the presence of nanosilica reduces the formation of ettringite. Moreover, the compressive strength of modified samples exhibited an upward trend. In the experimental sample manipulated with 1% nanosilica combined with 6% lime, the compressive strength increased by 1.84 MPa during the initial 7 days, representing an approximately 18-fold improvement compared to the control sample.

Using waste to improve the weak: Recycled seashell as an ideal way to regulate the interfacial transition zone in biochar-cement composites

The strategy of partially substituting cement with carbon-negative biochar to fabricate biochar-cement composites can represent a promising approach to reducing the carbon emissions of the construction industry. However, the detrimental impact on strength development from excessive biochar incorporation remains a significant challenge. To address this issue, this study pioneers a strategy to modify wood waste-derived biochar using seashell waste for enhancing its binding with the cement matrix. Employing a mechanochemical process, the shell-modified biochar was synthesized using oyster shell (OS) and wood waste (WW). The compressive strength of cement composites incorporating 5 wt% modified biochar improved by 3.9–17% compared to the referenced biochar. Even with high biochar incorporation (30 wt%), the compressive strength increased by 58.2% upon modifying the biochar at the OS/WW ratio of 1:9 (10SBC). The modified biochar refined the pore structures, accelerated the hydration kinetics, improved the degree of hydration, and fostered the development of the C-S-H gel network with a longer silicate chain and a higher polymerization degree. Furthermore, the strength enhancement of the biochar-cement composites was attributed to the improved micro-mechanical properties at the interfacial transition zone (ITZ), which increased the volume fraction of high-density C-S-H by 64.4–112% and decreased the low-density C-S-H fraction by 41.8–52.6%. Notably, 10SBC demonstrated a superior improvement due to its cohesive bond with the C-S-H gel and the concurrent densification of C-S-H in the ITZ, which was facilitated by the growth of Ca-/Al-rich hydration products. Overall, this study synergistically upcycled wood and seashell waste into value-added cement additives, thereby achieving strength enhancement of the cement composites.

Insight into Carbon Black and Silica Fume as Cement Additives for Geoenergy Wells: Linking Mineralogy to Mechanical and Physical Properties

Insight into Carbon Black and Silica Fume as Cement Additives for Geoenergy Wells: Linking Mineralogy to Mechanical and Physical Properties

Biofuel from wastewater-grown microalgae: A biorefinery approach using hydrothermal liquefaction and catalyst upgrading

Third-generation biofuels from microalgae are becoming necessary for sustainable energy. In this context, this study explores the hydrothermal liquefaction (HTL) of microalgae biomass grown in wastewater, consisting of 30% Chlorella vulgaris, 69% Tetradesmus obliquus, and 1% cyanobacteria Limnothrix planctonica, and the subsequent upgrading of the produced bio-oil. The novelty of the work lies in integrating microalgae cultivation in wastewater with HTL in a biorefinery approach, enhanced using a catalyst to upgrade the bio-oil. Different temperatures (300, 325, and 350 °C) and reaction times (15, 30, and 45 min) were tested. The bio-oil upgrading occurred with a Cobalt-Molybdenum (CoMo) catalyst for 1 h at 375 °C. Post-HTL, although the hydrogen-to-carbon (H/C) ratio decreased from 1.70 to 1.38–1.60, the oxygen-to-carbon (O/C) ratio also decreased from 0.39 to 0.079–0.104, and the higher heating value increased from 20.6 to 36.4–38.3 MJ kg−1. Palmitic acid was the main component in all bio-oil samples. The highest bio-oil yield was at 300 °C for 30 min (23.4%). Upgrading increased long-chain hydrocarbons like heptadecane (5%), indicating biofuel potential, though nitrogenous compounds such as hexadecanenitrile suggest a need for further hydrodenitrogenation. Aqueous phase, solid residues, and gas from HTL can be used for applications such as biomass cultivation, bio-hydrogen, valuable chemicals, and materials like carbon composites and cement additives, promoting a circular economy. The study underscores the potential of microalgae-derived bio-oil as sustainable biofuel, although further refinement is needed to meet current fuel standards.

Investigation on Strength and Flexural Behavior of PVA Fiber-Reinforced and Cemented Clayey Soil

Adding cement to soft soils may lead to brittle behavior and the occurrence of sudden damage. Methods to further improve the tensile and flexural properties of cemented clay are noteworthy topics. This paper mainly focuses on the effect of cement and moisture content on the strength and flexural properties of cemented clay reinforced by PVA fiber. The selected clayey soil was a kaolin with cement content of 5%, 10%, and 15% and moisture content of 50%, 56%, 63%, and 70%. The results show that the incorporation of 0.6% fiber can effectively improve the deformability of cemented clay in unconfined compression tests (UCS). The strengthening effect of fiber, as seen in the peak strength and post-peak strength of UCS, was significantly related to cement content. As the water content increased, the compressive strength of the fiber-reinforced cemented clay decreased, but its load-bearing capacity enhanced. When the cement content was 15%, the splitting tensile strength of fiber-reinforced cemented specimens increased by 11% compared to cemented soil, but the deformability of the specimens became poor. In the cement-content interval from 5% to 10%, the bending toughness was significantly improved. Sufficient cement addition ensures the enhancement of PVA fibers on strength and flexural properties of cement-stabilized clayey soil.

Bone Cement in Adult Hip and Knee Reconstruction: A Review of Commercially Available Options and Clinical Outcomes.

Polymethyl-methacrylate (PMMA) bone cement is used extensively in hip and knee arthroplasty. A thorough understanding of the basic chemistry underlying PMMA is important for orthopaedic surgeons because this underscores the specific way bone cement is used during surgery. Recently, clinical research has shed light on the various types of PMMA regarding the viscosity of the mixture and the effect of cement additives. These variations in composition may alter the clinical efficacy of implanted bone cement in hip and knee arthroplasty. Understanding these key differences will allow the surgeon to tailor the PMMA composition as needed to maximize outcomes of hip and knee arthroplasty. This review will summarize the preclinical feature of PMMA, evaluate current and past commercially available bone cement options, analyze preclinical results and clinical outcomes of various bone cement types, and highlight future areas of research.