Standard Portland Cement Research Articles

Formulation of high-recycled-content hydraulic cements based on alkali aluminosilicate chemistry and mechanochemical processing techniques

The current study investigates the potential of various waste materials and industrial by-products for formulating high-recycled content hydraulic cement, leveraging alkali aluminosilicate chemistry principles. Through rigorous characterization employing X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) Spectroscopy, thermogravimetric analysis (TGA), and Scanning Electron Microscopy (SEM), alongside alkalinity and alkali solubility assessments, the chemical and mineralogical compositions of waste brick, lime kiln dust, cement kiln dust, waste glass, gypsum, foundry sand, granulated blast furnace slag, and impounded coal ash were unveiled. Silicon and aluminum were found abundantly in these materials, with lime kiln dust and slag contributing calcium. A thoroughly crafted blend, enriched with alkalis, underwent mechanochemical activation to yield a hydraulic cement finely tuned to meet specific chemical ratios required for effective alkali aluminosilicate reactions. Upon hydration, this innovative cement exhibited rapid early strength development, achieving a commendable compressive strength of 32 MPa within 28 days a performance on par with standard Portland cement. Remarkably, the heat of hydration profiles revealed a prompt onset of hydration reactions, marked by a significant exothermic peak within the initial hours, in contrast to the gradual peak observed with Portland cement. TGA/DTA results further corroborated the thermal stability of the hydration products formed. Alkali-solubility assessments of the raw materials emerged as reliable indicators of their reactivity within the cement matrix, with solubility values exceeding 20 % for waste glass and impounded coal ash, signifying their high potential for alkali activation. The culmination of this research underscores the feasibility of re-composing waste materials to craft alkali aluminosilicate cement, offering performance akin to conventional options. These findings advocate for the adoption of sustainable material utilization in construction, paving the way for enhanced industrial symbiosis in cement production.

Investigation Of Usability of Sepiolite as a Pozzolan in Production of High Performance Cementitious Composites

The continuous growth of population and urbanization in the world significantly increases the demand for cement. In terms of sustainability, the cement industry needs to develop new and effective pozzolans with the appropriate recycling of alternative raw materials. It is also important to evaluate sepiolite, which has very limited resources in the world compared to other industrial minerals and whose economic deposits are limited to Spain and Türkiye. In this study, the usability of sepiolite as a pozzolan in cement and its effects on physical, mechanical and durability properties were investigated. First of all, the chemical and physical properties of sepiolite in Eskisehir region were investigated. Crude and ground sepiolite calcined at 500 ºC, 700 ºC and 900ºC were substituted for CEM I 42.5 R class standard Portland cement at 5-10-15% and 20% ratios. The pozzolanic activities of produced sepiolite substituted cement were determined according to ASTM C-311. As a result, crude sepiolite retains more water than calcined sepiolite, thus negatively affecting the strength properties of the concrete. Additionally, sepiolite is considered suspicious (harmful-harmless) in terms of alkali silica reactivity except 10%-15%-20% crude sepiolite substitutions. Overall, It has been observed that sepiolite does not have sufficient pozzolanic properties in cementitious composites.

A Study on Compressive Strength and Micro Structural Properties of Magnesium Oxychloride Cement Concrete Under Varying Temperatures of Magnesium Oxide

Abstract: Construction is a huge consumer of natural resources and a considerable contribution in terms of CO2 emissions. Manufacturing cement and construction materials was shown t be source of the most greenhouse gas emissions. This study looks at whether magnesium oxychloride cement (MOC) may be used as a concrete alternative to standard Portland cement to lessen the environmental effect of the building sector. The research process involves a thorough review of the literature, an experimental investigation, and an internal structural analysis based on the optimal molar ratio. In this investigation, MOC cement concrete was mixed with magnesium powder at varied temperatures. The use of heated magnesium oxide powder produces the first set of results. Finally, a change was made to increase compressive strength of MOC cement concrete. To stimulate the reaction or gel formation, heat was applied to MgO powder at various temperatures and added to the manufacturing of MOC cement to improve the compressive strength. The molar ratio is chosen from the journal for optimum mixing and simple casting of concrete cubes. SEM and EDAX are utilized to analyze the microstructure of the various raised temperature samples. The MgO, phases 3 and 5, are apparent as double and triple ribbons with shared boundaries with water molecules and chloride anions in the SEM images, showing that the strength has increased due to these phases. EDAX shows the proportion of elemental weight in the sample

Evaluating the biocompatibility of ceramic materials for constructing artificial reefs

IntroductionCoastal ecosystems, including reefs, are becoming increasingly threatened as anthropogenic development continues to encroach on intertidal habitats with little initiative to establish ecologically considerate infrastructure. Submerging human-made, shelter-providing structures known as artificial reefs (AR) can contribute to the preservation of these ecosystems. ARs are historically used for promoting the abundance and biodiversity of marine species for aquaculture, conservation, and ecotourism; and are typically made of concretes or metal structures. An AR’s success correlates to its ability to establish a surface layer of microorganisms, such as microalgae and bacteria, known as a biofilm. The productivity of the biofilm can be influenced by material surface properties. It is hypothesized that material pH and porosity affect the rate of biofilm formation.MethodsHere - a range of concrete mixtures were cast and submerged in circulating seawater and mass per surface area of biofilm accumulation was measured to evaluate this theory. These mixtures included standard Portland Cement (PC), PC with admixtures of diatomaceous earth (PDC) and limestone (PLC), fine-aggregate high-performance concrete (DUC), and terra cotta (TER). ARs were manufactured as 38mm tall cylinders, 76mm in diameter, and submerged in circulating seawater to evaluate mass per surface area of biofilm accumulation.ResultsOur results indicate that biofilm formation is directly affected by surface porosity and less-so by pH, as determined by measuring material properties after submersion. We found that the PDC samples were most successful in forming a biofilm despite being more fragile than other concrete samples.DiscussionThis preliminary study provides insight into how different material properties influence the accumulation of biofilm as a starting point for designing ARs. Future work will investigate the long-term performance of such samples in relevant conditions.

Prediction of concrete strength considering thermal damage using a modified strength-maturity model

The maturity method is widely used to estimate early-age concrete strength. However, the traditional maturity models exhibit limited predictive capability for late concrete strength under thermal curing conditions due to the influence of the “crossover effect”. This study developed a curing scheme for Standard Portland cement concrete in the absence of supplementary cementitious materials at temperatures ranging from 5 °C to 50 °C and analyzed the temperature variations inside thermally cured concrete specimens. The findings reveal that an increase in curing temperature and time between 30 °C and 50 °C and 8 and 72 h respectively led to an increase in the early strength and a decrease in the late strength of concrete, due to the “crossover effect”. Additionally, a linear relationship was found between curing temperature and the late strength reduction coefficient. Utilizing this relationship, a modified maturity model that considers the “crossover effect” was proposed, improving the accuracy of predicting concrete strength under thermal curing conditions (with a prediction error of less than 10%). The research outcomes are of significant guiding significance for winter construction by ensuring the quality of concrete, reducing construction accidents, and improving construction efficiency.

Effect of partial cement replacement with sugarcane bagasse ash

Research into mixing and replacing the component ingredients of concrete has become necessary since there is a widespread need in most parts of the globe for more affordable housing and the discovery of an alternative to standard Portland cement. Despite the fact that a great number of investigations have been carried out to evaluate the viability of combining cement with sugarcane bagasse ash and sand with laterite soil, no research has been conducted on the influence that combining the two materials has on the characteristics of concrete. This study presents the findings on the strengths, permeability, and structural behaviour of concrete beams containing sugarcane bagasse ash and laterite soil. The goal of the research was to combine traditional concrete with sugarcane bagasse ash to produce sugarcane bagasse ash laterised concrete, which could be used for the construction of low-cost housing. Ash from sugarcane bagasse and lateritic soil were used as blenders and blended with regular concrete materials. Cement was largely replaced with sugarcane bagasse ash in the following proportions by mass: 0%, 5%, 10%, and 15%. The impact of different degrees of material substitution on the workability and compressive strength of concrete was investigated using a concrete mixture with the proportions 1:2:4 and a water-to-cement ratio of 0.55. The same mixture was utilised, but this time with a continuous slump of 30mm+3mm. This was done in order to assess the influence of different degrees of combination material replacement on the characteristics of concrete and the behaviour of structural beams.

Effects of Al2O3, SiO2 nanoparticles, and g-c3n4 nanosheets on biocement production from agricultural wastes

Environmental issues are brought up concerning the production of Portland cement. As a result, biocement serves as a reliable substitute for Portland cement in green construction projects. This study created a brand-new technique to create high-quality biocement from agricultural wastes. The technique is based on nanomaterials that improve and accelerate the "Microbially Induced Calcite Precipitation (MICP)" process, which improves the quality of the biocement produced. The mixture was further mixed with the addition of 5 mg/l of graphitic carbon nitride nanosheets (g-C3N4 NSs), alumina nanoparticles (Al2O3 NPs), or silica nanoparticles (SiO2 NPs). The cement: sand ratio was 1:3, the ash: cement ratio was 1:9, and water: cement ratio was 1:2. Cubes molds were prepared, and then cast and compacted. Subsequent de-molding, all specimens were cured in nutrient broth-urea (NBU) media until testing at 28 days. The medium was replenished at an interval of 7 days. The results show that the addition of 5 mg/l of g-C3N4 NSs with corncob ash delivered the highest “Compressive Strength” and the highest “Flexural Strength” of biocement mortar cubes of 18 and 7.6 megapascal (MPa), respectively; and an acceptable “Water Absorption” (5.42%) compared to all other treatments. This treatment delivered a “Compressive Strength”, “Flexural Strength”, and “Water Absorption” reduction of 1.67, 1.26, and 1.21 times the control (standard Portland cement). It was concluded that adding 5 mg/l of g-C3N4 NSs to the cementitious mixture enhances its properties, where the resulting biocement is a promising substitute for conventional Portland cement. Adding nanomaterials to cement reduces its permeability to ions, increasing its strength and durability. The use of these nanomaterials can enhance the performance of concrete infrastructures. The use of nanoparticles is an effective solution to reduce the environmental impact associated with concrete production.

Experimental and Analytical Study on Performance of Fiber-Reinforced Self-Stressed Concrete

Expansive cement is a unique type of cement that, when mixed with water, produces a paste which expands in volume significantly more than standard Portland cement. This expansion nullifies the deficit of shrinkage that arises during concrete hardening. This paper presents the outcomes of two phases of experimentation. Phase I of the paper provides a summary of the performance of expansive cement concrete mixes prepared with various proportions of expansive cement, which partially supplements the ordinary Portland cement, and which is infused with varying amounts of PVA fibers of 0.5, 1, 1.5, 2, and 2.5%, as a form of reinforcement under compression, tension, and flexure. Concrete strength, curing effect, and PVA fibers are the variables in Phase I of the study. The Phase II findings provide the buckling behavior of the self-stressed concrete columns reinforced with PVA fibers when the optimum concrete mix obtained from the Phase I investigation was poured inside steel tubes of varying thicknesses of 2 mm and 2.5 mm to restrict the expansion of the concrete, thereby making it self-stressed concrete. The D/t ratio, inclusion of expansive cement, and PVA fibers are the variables for Phase II of the study. The self-stressed columns with 2% PVA fibers showed better performance than the other columns.

Study of Linear Deformation Changes in Heavy Concrete Based on Modified Portland Cement

The investigation results revealed how modified standard Portland cement of grade 42,5 (M400) with 10% of the expanding additive changes the deformation characteristics of heavy concrete. Heavy concrete of class B 22.5 (M300) with a different water-cement ratio (slump 3 cm and 5 cm) was selected as the object of study, from which cubic specimens of side 10 cm were prepared. The impact of modified cement on concrete linear deformations is determined at the ages of 1, 3, and 28 days under normal setting conditions, and changes in the sizes of the same specimens are checked for three months under air-drying conditions. The study confirmed that the most effective impact of modified cement, as in the case of construction mortars, is also observed in 3–7 days of curing. It was found that the effect of modified cement is increased with the increase in the water-cement ratio, and a relatively low percentage of expansion through the low water-cement ratio is explained by the certain rigidity of the concrete internal structure.

SYNTHESIS AND CHARACTERIZATION OF CARBOXYMETHYL CELLULOSE (CMC) FROM DIFFERENT WASTE SOURCES CONTAINING CELLULOSE AND INVESTIGATION OF ITS USE IN THE CONSTRUCTION INDUSTRY

This study aimed at the recovery of cellulose from abundantly available wastes and its sustainable application. Firstly, in the cleaning process, cellulose-containing wastes, such as “air particle vacuum powder” (APVD), “towel clippings” (TC), and “cottonseed delintation residues” (CD), were thoroughly washed, separately, with tap water to remove some organic and inorganic impurities. The cotton slurry was purified by 17.5% NaOH at 90 oC for about 4 hours, then filtered and washed with tap water. Afterwards, the resulting pulp was bleached by NaOH and H2O2, and washed with distilled water until neutralized. Secondly, for the synthesis of carboxymethyl cellulose (CMC) from the above-dried celluloses, optimum conditions were achieved by varying the concentrations of components and ambient conditions. In the sample coded TCCMC3, a maximum degree substitution (DS) of 1.22, the highest consistency, the highest penetration time and the highest viscosity with 2520 centipoises (cP) were obtained from the reaction of towel clippings with 5.62 g sodium hydroxide and 13.12 g monochloroacetic acid (MCA) at 65 oC for 3 hours. Finally, the effect of these synthesized CMCs on the consistency and penetration time of a cement paste was investigated. The consistency of standard Portland cement (PC), without CMC addition, was 5 mm in the Vicat test, while the values measured for the cement pastes to which TCCMC3, APVDCMC3 and CDCMC3 were added reached 36.5 mm, 28.0 mm and 13.0 mm, respectively. While the setting time in the standard sample (Portland cement paste, PCP) was between 2.20-4.10 hours, this time shifted to 3.30-7.00 hours, with a maximum setting time recorded with the addition of TCCMC3. Besides, while the penetration time for APVDCMC3 started at 3.10 hours and was completed at 5.30 hours, for CDCMC3, it ranged between 2.40 and 4.40 hours, leaving it without hydration in a higher time interval than in the case of standard Portland cement paste. As a result, it has been found that carboxymethyl cellulose synthesized by the etherification reaction of cellulose obtained from recycled wastes for industrial uses, in an aqueous alkali environment, can be applied as a thickener in the construction industry and other fields.

The influence of foams, having different expansion ratios, on the structurization of thermal insulation foam concrete

Introduction. The article addresses the influence of foams, having different origins and expansion ratios, on the structurization of thermal insulation foam concrete. The study is focused on solving the problem of the binder hydration conditions in the interpore space of the foam concrete mixture and maintaining its stability. The goal is to design an economically effective composition. Materials and methods. To analyze the structurization process, foam concrete samples, featuring average density grades D300 and D500, were made using ordinary Portland cement. The nature of the surfactant substance of the foam, its expansion ratio and the water-cement ratio of the solution are the variable factors determining parameters of the material structure. The strength of the foam concrete was used to evaluate the cement hydration conditions. The strength was identified according to GOST 10180. Parameters of the macrostructure were measured using the Levenhuk optical microscope and the LevenhukLite software. Results. It is found that hydration in the interpore space of the mixture is implemented to the fullest extent when a protein foaming agent, featuring a low foam expansion ratio, is used. The foam concrete, thus made, has closed pores, whose diameter varies in a small range of values, while the partition thickness exceeds the maximum size of the cement grain. An increase in the foam expansion ratio and a low value of the water-cement ratio of the solution lead to the uneven distribution of air in the mixture and reduce the thickness of the interpore partition. In this case, the structure of the foam concrete is “friable”; it represents conglomerates of interconnected pores. Conclusions. Since the geometry of the macrostructure of the material has a significant influence on the heat transfer process and strength, the protein foaming agent, featuring a low foam expansion ratio, is preferable for the production of thermal insulation foam concrete using standard Portland cement without re-grinding. Otherwise, a higher foam expansion ratio foam requires an increase in the specific surface area of the binder.

Investigation on Concrete with M-Sand and Silica Fume

The global construction industry uses a significant amount of concrete. In India, the ordinary concrete is created utilizing natural sand from river beds as fine aggregate. Because dwindling natural resources constitute an environmental risk, government restrictions on sand mining have led to a shortage and a sharp rise in the price of the material. The optimization of M-Sand with silica fume as a partial replacement for natural sand is discussed in this work. Compressive and split tensile strengths of concrete mixtures were assessed. Natural sand was substituted with manufactured sand in five proportions of 0, 10, 20, 30 and 40%, while silica fume was substituted for standard Portland cement in amounts of 0, 5, 7.5 and 12.5%. The findings showed that concrete with 30% M-Sand and 7.5% silica fume has increased compressive and split tensile strength.

Performance of fly ash based geopolymer concrete with partial replacement of fine aggregate by steel mill slag

Many of these wastes can be recycled or reused in recent years. As a building material in concrete, some of these can reduce landfill costs and protect the environment from negative effects. The recycling and use in the construction sector of industrial byproducts complement sustainable technology and development considerably. Geopolymer is an environmentally sustainable replacement for the standard Portland cement binders, a new generation of binding material. As an alkaline activator, sodium hydroxide solution with 12 mol and sodium silicate was used. The alkaline liquid to fly ash ratio in all the mixes is 0.4. Consider the oven temperature of 70 °C for 48 h and the curing conditions in the environment. The compressive strength, water absorption, and density of the concrete were all measured on each specimen. According to the tests, the compressive strength increases as the amount of steel mill slag increases. Steel mill slag is the alternative fine particle in geopolymer concrete.

Dynamic and Analysis of A Geo-Polymer Concrete Structure

The standard portland cement (OPC) was traditionally used as the binding agent in concrete. However it is also important to find alternative emissions-free concrete binding agents to reduce environmental damage caused by cement manufacturing. Geopolymers, also known as inorganic polymers, use byproducts like fly ash rather than cement. Recent studies have shown that geopolymer concrete based on fly ash has enough properties for use. As the geopolymer strength mechanism is different from the OPC binder, an appropriate constituent model for geopolymer concrete must be obtained in order to predict the load-deflection behavior and strength of geopolymer concrete structural components. A number of problems faced with today's cement industry are addressed by geopolymer binders. These binders have similar or better engineering qualities in comparison with cement and can use many types of waste materials.
 This project describes the seismic analysis of buildings with high-rise structures, the model of residential G+10 buildings with traditional concrete and geopolymer concrete properties is modelled and analysis is carried out using the response spectra method considering the position of the building in zone III, this analysis would generate the effect of higher vibration modes and real force distribution in elastic range. Test results include maximum story shifts, maximum story drifts, story shears and story stiffness, and an efficient lateral load resistance system, helping to establish whether geo-polymer concrete can be used in high-rise building construction as dynamic loads are included in the high-rise structures

Effectiveness on mechanical properties of m60 grade scc with partial replacement of cement by different mineral admixture like ggbs, lime powder and metakaolin at various percentages

Production of cement brings about the discharge of green house gases which at last prompts an unnatural weather change on one hand. On other hand consumption of crude materials like lime stone. So by utilizing elective materials we can lessen the creation of cement. Presently a day’s the majority of the analysts are centered around replacement of cement with other mineral admixtures like Ground granulated blast furnanace slag(GGBS),Metakaolin and lime powder and so forth without bargaining its mechanical properties and durability. Self compacting concrete doesn’t need vibration for setting and compaction. This paper presents the outcomes on various mechanical properties of self compacting concrete utilizing the standard Portland cement, GGBS, lime powder and metakaolin as binding material in making concrete. The hardened concrte properties like compressive strength, split tensile strength and flexural strength are found in trial work and comparison made with normal concrete.

Corrosion resistance and mechanical properties of Armakap cement for nuclear applications

Nuclear waste containers are prone to environmental degradation – over time, corrosion/erosion can cause the leakage of radioactive material which is a significant safety hazard. In the current work, environmental degradation of magnesium phosphate cement formulated by Armakap (2020, 3030) is investigated by using corrosion/erosion circulators that provide both acidic and saline environments. Test results indicate that Armakap formulations have reduced mass loss due to acidolysis by more than a factor of two in highly acidic conditions relative to a standard Portland cement sample. Additionally, the mechanical strength of Armakap 2020 formulation surpass that of Portland cement while Amrakap 3030 depicts a minor reduction. Although the Armakap 3030 provides good corrosion resistance, we conclude that Armakap 2020 shows optimal performance and is better suited than conventional Portland cement for a variety of nuclear waste storage applications at temperatures not exceeding 55 °C.

Reinforcement of cement mortar with alumina nanofibers

The article discusses the possibility of using alumina nanofibers to reinforcement cement mortar. Nanofiber is a twisted conglomerate, and its ultrasonic treatment in the water allows obtaining a stable dispersion. The research has been carried out on the effect of nanofibers on the viscosity of cement paste, as well as on the reinforcement of cement mortar. At concentrations less than 0,2%, there is no significant effect of nanofibers on the viscosity of the system. The studies were carried out on standard Portland cement at a water-cement ratio of 0.27. Reinforcement of cement mortar with aluminum oxide, with a concentration of 0 to 0.1%, does not give a significant change in the microstructure of the material. It was shown in the work that the use of nanofibers makes it possible to increase the strength of the system by 20% in compression and by 45% in bending.

Ultrasonic Pulse Velocity—Compressive Strength Relationship for Portland Cement Mortars Cured at Different Conditions

The purpose of this paper is to establish some correlations between the main technical parameter with regard to the cement-based materials technology, the 28-day compressive strength, and ultrasonic pulse velocity of standard mortar samples cured at three different conditions—(i) under water at 22 °C; (ii) climatic chamber at 95% RH and 22 °C; (iii) lab ambient, 50% RH, and 22 °C—and after five curing periods of 1, 2, 7, 14, and 28 days. Good correlations for each curing conditions were obtained. All the positive linear relationships showed better R2 than exponential ones. These findings may promote the use of ultrasonic pulse velocity for the estimation of the 28-day compressive strength of standard Portland cement samples within the factory internal quality control.

Application of expanding cements for sprayed concrete in tunnel construction

Introduction. The paper substantiates the actuality of the problem connected with obtaining efficient fine concretes possessing enhanced crack resistance, tightness, and duration for tunnel construction. This aim is pursued with the application of expansive cements (EC).
 Materials and methods. Various types of expansive agents were used in composition binders. Portland cement PTs 500 D0 was taken as the basic Portland cement. Studying hydration and structure formation processes during hardening of the ECs and EC-based concretes was executed utilizing a system of physicochemical methods. Assessment of construction and technical properties of the fine concretes based on composition binders was accomplished using standard research methods.
 Results. Analysis results are given for the effect of type and amount of the expansive agents on strength and volume deformation values of the concretes used in tunnel installation construction. Improvement of physical, mechanical, and technological properties and performance of sprayed concrete is shown. A general mechanism of influence of expansive additives (EA) on fine concrete properties is established. A classification of expansive cements for solving various tasks in tunnel installation construction is suggested.
 Conclusions. EA application efficiency is theoretically substantiated and experimentally proved for the case when the EA is used as an active agent in the composition binder for sprayed concrete in tunnel construction. General enhancement of technical indicators of concrete mixture and concretes is determined. EA classification is suggested for the different extent of hydrated EA expansion and various construction tasks. Replacement of standard Portland cement for an EC for underground structures concrete used in tunnel construction provides a significant increase in their maintainability.

Synthesis and characterisation of Portland cement clinker by exploiting waste oyster shells and alumina sludge

Significant quantities of oceanic waste oyster shells and drinking water treatment plant sludge (alumina sludge) raise serious issues on eco-toxicology and environmental protection. In order to manipulate these issues, the present research work investigates the valorisation capability of the mentioned waste materials as raw meal substitutes for Portland clinker production. The clinkers and their respective cements thus obtained have been structurally characterised by various structural analysis techniques including, X-ray fluorescence, scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. Structural analysis results reveal that the replacement of clinker raw materials by waste oyster shells and alumina sludge positively influences the morphology of the formed clinker/cement. In addition, the development of compressive strength of this waste-based cement has been found similar to that of standard Portland cement (type 52.5N) which justifies its commercialisation potential. A detailed account of the interpretations of invaluable physico-chemical parameters regarding the clinker/cement along with the prospective applications of the present study is also discussed.