Addition Of Cement Research Articles

A composite low-carbon cement strategy: High ferrite cement with addition of ferroaluminate cement

A composite low-carbon cement strategy: High ferrite cement with addition of ferroaluminate cement

Insights into the mechanics of uncemented and lightly cemented compacted iron ore tailings under high confining pressures

Grading changes due to particle breakage are crucial in geotechnical engineering problems involving high pressures, such as elevated-height dry stacking facilities for compacted filtered iron ore tailings disposal. However, understanding the iron ore tailings response at high stress is still in its early stages in the Brazilian context. It is now marked by the increasing need for alternatives to tailings allocation rather than the traditional slurry disposal in impoundments. The present research, which examines the mechanical response of iron ore tailings and lightly cemented iron ore tailings over confining pressures ranging from 1.2 to 120 MPa for dry stacking purposes, provides significant insights into this area. The study relied on triaxial tests conducted on a high-pressure apparatus that employed specimens compacted at three different compaction degrees. The cement addition incurred slight differences in isotropic compression, enlarging the range of achievable states. Still, the shearing response of both uncemented and lightly cemented tailings was very similar, particularly at higher stress levels, resulting in an equivalent critical state locus. In the v- ln ṕ plane, an S-shaped function described the critical state and delineated the regions where particle breakage becomes an important source of volumetric strain. In brief, this study provides novel insights into the behaviour of uncemented and lightly cemented iron ore tailings in the context of elevated-height dry stacking facilities.

ETUDE COMPARATIVE DES CARACTERISTIQUES DU SOL PAR STABILISATION AU CIMENT ET A LA CHAUX EN CONSTRUCTION ROUTIERE : CAS DU SOL DE BUGANGA A MINOVA/PROVINCE DU SUD KIVU/RDC

This work focused on the comparative study of soil stabilization with cement and lime. The purpose of this study is to carry out a comparative study of the stabilization of soil with cement and lime in order to increase the bearing capacity of the Minova soil to enhance this soil for use in road constructions (base layers and road bed) but also to contribute to the identification of this soil by studying the influence of stabilizers on the characteristics of the Minova soil. To achieve the expected results. Tests for the determination of the parameters of identification, compaction (modified Proctor) and bearing capacity (CBR) on the soil of BUGANGA in its natural state and after stabilization with cement and lime. The results obtained showed that the soil of BUGANGA is made up of 47.25% of the fines, therefore classified as fine soils. As far as the type of soil is concerned, it is a sandy clay with little plasticity characterized by a low bearing capacity (CBR=5.37%) with a medium swelling. Thus, due to its low load-bearing capacity, the BUGANGA soil has been stabilized to increase its bearing capacity. The results obtained showed that the addition of cement and lime increases the bearing capacity of the BUGANGA soil. Hence, by adding different contents of cement and lime, the CBR increased from 5.37%. In various stabilization formulations with lime and cement, BUGANGA soil is suitable for use in pavement beds.

Comprehensive Comparative Review of the Cement Experimental Testing Under CO2 Conditions

Global warming is presently one of the most pressing issues the planet faces, with the emission of greenhouse gasses being a primary concern. Among these gasses, CO2 is the most detrimental because, among all the greenhouse gasses resulting from anthropogenic sources, CO2 currently contributes the largest share to global warming. Therefore, to reduce the adverse effects of climate change, many countries have signed the Paris Agreement, according to which net zero emissions of CO2 will be achieved by 2050. In this respect, Carbon Capture and Sequestration (CCS) is a critical technology that will play a vital role in achieving the net zero goal. It allows CO2 from emission sources to be injected into suitable subsurface geological formations, aiming to confine CO2 underground for hundreds of years. Therefore, the confinement of CO2 is crucial, and the success of CCS projects depends on it. One of the main components on which the confinement of the CO2 relies is the integrity of the cement. As it acts as the barrier that restricts the movement of the sequestrated CO2 to the surface. However, in a CO2-rich environment, cement reacts with CO2, leading to the deterioration of its physical, chemical, transfer, morphological, and mechanical properties. This degradation can create flow paths that enable the leakage of sequestered CO2 to the surface, posing risks to humans, animals, and the environment. To address this issue, numerous studies have investigated the use of various additives in cement to reduce carbonation, thus enhancing the cement’s resistance to supercritical (sc) CO2 and maintaining its integrity. This paper provides a comprehensive review of current research on cement carbonation tests conducted by different authors. It includes detailed descriptions of the additives used, testing setups, curing conditions, methodologies employed, and experimental outcomes. This study will help to provide a better understanding of the carbonation process of the cement sample exposed to a CO2-rich environment, along with the pros and cons of the additives used in the cement. A significant challenge identified in this research is the lack of a standardized procedure for conducting carbonation tests, as each study reviewed employed a unique methodology, making direct comparisons difficult. Nonetheless, the paper provides an overview of the most commonly used temperatures, pressures, curing durations, and carbonation periods in the studies reviewed.

Porosity and cement controlling the response of artificially cemented tailings under hydrostatic loading to high pressures

Cemented tailings find various applications in mining, such as open-pit and underground backfill, dam decommissioning and filtered tailings stacking. This research investigates the compression behaviour of iron ore tailings (IOT) mixed with distinct amounts of Portland cement and compacted in different conditions through isotropic compression, pulse velocity, and unconfined compression tests. The results show the adequacy of the porosity/cement index (η/Civ) in predicting elastic and plastic characteristics of compacted filtered IOT - Portland cement blends, an original correlation that has not been reported by previous work. This index is useful in selecting the cement content and target density for essential parameters required to design cemented IOT stacks. Besides, both cement addition and compaction have promoted the tailings isotropisation (conversion of an anisotropic system to an isotropic one). The evolution of the Post-Yield Compression Line (PYCL) with cementation is shown. Finally, it is demonstrated that distinct initial (after compaction) porosities of uncemented specimens reach a unique PYCL after isotropic pressures above 100 MPa, and cemented specimens do not reach a unique PYCL even at 120 MPa of isotropic pressures. The results underscore the requirement of rigorous compaction control in the field and offer a methodology for the dosage and technological control of artificially cemented tailings.

Enhancing concrete pavement performance using refuse derived fuel fly ash as a sustainable cementitious material

ABSTRACT The utilization of waste materials in concrete is becoming increasingly important for sustainability in construction. This research investigated the mechanical performance and environmental safety of concretes containing Refuse Derived Fuel fly ash (RDF FA), a waste product from waste incineration plants. The innovative mix design strategically used RDF FA as both cement replacement and cementitious addition in concrete. Compressive and flexural strength test results showed that RDF FA addition increased both compressive and flexural strengths, while RDF FA replacement decreased strengths (< 28 days cured) compared to those of traditional cement concrete. Microstructural and mineralogical analyses revealed dense C–S-H formation in RDF FA added samples, indicating improved hydration. In contrast, RDF FA replacement reduced cementitious products and hindered hydration. RDF FA’s high SiO2 content and favourable SiO2/CaO ratio enhanced pozzolanic reaction in RDF FA added samples, further improving strength development. Leaching test results demonstrated that heavy metal concentrations in RDF FA-modified concretes remained within environmental protection limits. Thus, with proper mix design, RDF FA has the potential to be a sustainable supplement for concrete, reducing industrial waste and natural resource use. This work provides an approach to balance enhanced concrete performance with environmental safety when using RDF FA.

Effect of Size-Controlled Nanofluid on Mechanical Properties, Microstructure, and Rheological Behavior of Cement Slurry for Oil Well Cementing.

The optimal design of cement slurry by balancing various cement additives and cement is critical for effective oil well cementation job. However, given adverse circumstances of application, existing additives may not be sufficient to perform suitably in challenging conditions, leading to premature cement hydration, formation of microcracks, and gas channeling pathways. Thus, this study explores the use of a single-step silica nanofluid (NP size: 5-10, 90-100, and 250-300 nm and concentration: 1, 3, and 5 wt %) as an additive and explores its effect on thickening time, fluid loss, and rheological behavior of class G cement slurry at high-pressure and high-temperature (HPHT) conditions (135 °C and 3625 psi). The improvement in thickening time, fluid loss, and rheology of conventional slurry was greater for low NP size than the nanofluid of high NP size: the nanofluid size, e.g., 5-10 nm, and concentration (1 wt %) were found to accelerate the thickening time by 30-40% while reducing fluid loss from 38 mL (no silica, slurry CS) to 30 mL (with silica, slurry C1). The rheological behavior was studied via shear (viscosity) and dynamic (elastic moduli, G') modes to evaluate the viscosity, hysteresis, and elastic response of slurry with and without nanofluid. The inclusion of nanofluid slightly reduced the slurry viscosity; however, all slurries exhibited shear thinning with superior fitting with the power law model. As compared to slurry CS, hysteresis of slurry C1 was least dependent on shear deformation, and thus, it showed that it almost matched viscosity profiles during loading and unloading cycles. The addition of silica was found to maintain the original properties of cement slurry, establishing that cement had not agglomerated, and no sedimentation was observed even at shear rates of 1000 s-1. The results of this study greatly promote the use of silica nanofluid as an important additive in class G cement for cementation operations, which is unlikely with a two-step nanofluid where nanoparticles are expensive, and upon mixing, they tend to agglomerate and make large size clusters.

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.

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.

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.

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.