Performance Of Cementitious Composites Research Articles

Influence of the Addition of TiO2 Nanoparticles on the Self-Cleaning Capacity of Cementitious Composites.

This study evaluated the potential of incorporating TiO2 nanoparticles (NT) into cementitious composites to provide self-cleaning and self-sanitising properties, as well as the partial replacement of natural aggregates with recycled glass (RGA), ceramic brick (RBA), granulated blast furnace slag (GBA), and textolite waste (RTA) from electronic equipment on these properties. Based on the research results, the addition of NT to cementitious composites led to a significant reduction in contact angle, which means an increase in surface hydrophilicity. At the same time, Rhodamine B stain fading was highlighted, with the degree of whiteness recovery of NT composites exceeding that of the control by up to 11% for natural aggregate compositions, 10.6% for RGA compositions, 19.9% for RBA compositions, 15% for GBA compositions, and 13% for RTA compositions. In a mould-contaminated environment, it was shown that the introduction of NT allowed the material to develop a biocidal surface capacity which is also influenced by the nature of the aggregates used. Furthermore, the study revealed that, under controlled conditions, certain recycled waste aggregates, such as textolite, promoted mould growth, while others, such as brick and slag, inhibited it, highlighting not just the effect of the addition of NT, but also the significant influence of the aggregate type on the microbial resistance of cementitious composites. These improvements in the performance of cementitious composites are particularly advantageous when applied to prefabricated elements intended for the finishing and decorative surfaces of institutional (schools, administrative buildings, religious structures, etc.) or residential buildings.

Carbon dioxide sequestration in cementitious materials: A review of techniques, material performance, and environmental impact

The release of carbon dioxide (CO2) into the earth's atmosphere is a substantial global environmental concern that arises from the processes of industrialization and urbanization. The increase in atmospheric CO2 concentrations has resulted in the phenomenon of global warming and subsequent alterations in climate patterns. Accelerated CO2 sequestration in cementitious materials is currently the subject of extensive research as a highly efficacious approach to mitigating the carbon footprint of the concrete industry. The sequestration procedure entails the transformation of gaseous CO2 into carbonate minerals. The review presented in this paper outlines the most recent carbonation (i.e., CO2 sequestration) techniques, such as mineral carbonation, accelerated CO2 curing (ACC), pre-carbonation, and carbonation mixing, that have been recently explored. The potential of mineral carbonation of industrial wastes and the advantages of their incorporation in the concrete matrix is investigated. Carbonation technologies and their effect on the performance of cementitious composites are reported. Information on life cycle assessment are also included to evaluate the environmental impact associated with the production of carbonated materials. Various commercialized CO2 utilization technologies in construction sector, such as CarbonCure, Solidia, Carbstone, Calera, and Carbon8 are reviewed. Moreover, this review offers a thorough insight into the carbonation technologies, evaluating their advantages, limitations, and the existing gaps in research.

Influence of Luffa fibers thermomechanical treatment and ceramic roof tile waste on performance of cementitious composites

The performance of vegetable fibers and the insertion use of different residues in as substitution for cement are important crucial factors to be evaluated to assess in composites. Therefore, this research aims to evaluate the efficiency of thermomechanically treated vegetable fibers and the replacement of 40% of the cement mass with ceramic roof tile waste (CRW) in fiber-cement composites. Thermomechanical treatment of Luffa cylindrical fibers (LC) at 160 °C resulted in reduced absorption in composites with added ceramic roof tile waste (CRW-160) after 1 year of aging. This indicated improved mechanical performance and durability compared to composites with natural fibers. In the CRW-160 matrix, no cracks were observed, and the fibers exhibited greater pullout. The results of aged composites (CRW-160) demonstrated superior performance compared to matrices with only cement and LC fibers, as well as composites with a 40% cement replacement by CRW. This suggests that the combined use of thermomechanically treated LC fibers and partial cement replacement with CRW can enhance composite durability, reduce cement usage, and increase the utilization of discarded waste.

Investigation of cementitious composites reinforced with metallic nanomaterials, boric acid, and lime for infrastructure enhancement

<abstract> <p>Nanomaterials integration within construction materials could promote the generation of more sophisticated structural materials, as it imbues reinforcement at the nanoscale. This research adopted experimental approaches to assess the influence of metallic nanomaterials on the performance of cementitious composites with various ratios of boric acid (1%, 3%, and 5% by sand's weight) and lime (0.5%, 1.5%, and 2.5% by sand's weight), respectively, for use in construction infrastructure facilities. This research provides valuable insight into the potential of using boric acid and lime as well as metallic nanomaterials to strengthen cement-based composites. Initial curing stages revealed a notable decrease in compressive strength attributed to the inhibitory effects of boric acid and lime on cement hydration. However, the introduction of TiO<sub>2</sub> nanoparticles demonstrated significant enhancements in compressive strength and durability. Statistical analysis emphasized the significance of nanomaterials in augmenting compressive strength, with implications for long-term performance. This study has shown that the addition of nano-titanium dioxide TiO<sub>2</sub> can significantly enhance the compressive strength of Portland cement mortars, particularly when used in conjunction with appropriate ratios of boric acid and lime. The results of the 7 days test indicated that the inclusion of boric acid and lime in the cement mortars significantly decreased the compressive strength. However, the addition of nano-TiO<sub>2</sub> to cement mortars containing 1% boric acid and 0.5% lime resulted in a 31-fold increase in compressive strength compared to cementitious composites without nano-TiO<sub>2</sub>. In contrast, the compressive strength significantly increased by 1.2 times, 85.3 times, and 65.1 times, respectively, after 56 days for the addition of boric acid (1%, 3%, and 5%) with lime (0.5%, 1.5%, and 2.5%), respectively, in the presence of nano-TiO<sub>2</sub>, compared to the 7 days strength. The results also illustrated that, in general, the incorporation of various types of nano-TiO<sub>2</sub> into cementitious composites containing boric acid and lime increases their compressive strength as the ratios of boric acid and lime increase, as long as sufficient curing time is allowed.</p> </abstract>

Hydration kinetics, microstructure and physicochemical performance of metakaolin-blended cementitious composites

This paper presents a comprehensive investigation on influences of metakaolin on the early and later performances of cementitious composites. Systematic measurements from hydration to physicochemical performance and thermodynamic modeling based on ternary compatible phase diagram were carried out. Different fineness of metakaolin with d50 of 25, 15.3 and 3.37 μm was adopted to replace ordinary Portland cement. The replacement level of metakaolin varied at 5 %, 10 %, 15 % and 20 %. Effects of metakaolin in view of pozzolanic activity and filling capacity on the microstructural formation of cementitious composites were quantified based on the Frattini test and the strength activity index. It is found that a higher addition or specific surface area of metakaolin decreases the fluidity of cementitious composites and meanwhile the setting time was delayed. The filling effect of metakaolin on cement hydration works primarily in the early 3 d while pozzolanic effect plays a major role afterwards. The relationship between particle size of MK and its pozzolanic activity becomes pronounced for metakaolin content greater than 10 %. The presence of metakaolin contributes to strength development mainly at late age. Finer particle size of metakaolin does not ensure a pronounced filling effect, which depends on the content of metakaolin. The metakaolin with high fineness d50 = 3.37 μm enables to promote cement hydration. The decrease of metakaolin particle size results in a higher content of C-A-S-H and high alumina-rich hydrates, as demonstrated by both experiments and simulation.

Comparison of effectiveness of blending and impregnation applications of dispersed nanoparticles on performance of cementitious composites

Blended or impregnated forms of nanomaterials in cementitious composites play a key role in determining mortar performance. In this study, the performance of graphene oxide (GO), silver nanoparticles (AgNPs), pristine multi-wall carbon nanotubes (MWCNTs), and functionalized MWCNTs impregnated and blended cementitious composites were compared using principal component analysis (PCA). The highest recorded compressive strength at 28 days was 39.1 MPa corresponding to the impregnation of carboxylated MWCNTs, representing a 29% improvement compared to reference cementitious composites while blending of pristine MWCNTs achieved a maximum compressive strength of 50.37 MPa, representing a 45% improvement over the reference. The group of GO, low-density AgNPs, and hydroxylated MWCNT-impregnated cementitious composites achieved the best sulfuric acid resistance, with an average compressive strength of 30.15 MPa, water absorption of 21.82%, porosity of 36.29%, and ultrasonic pulse velocity of 2.91 km/s due to preventing harmful sulfate ions entering their structure. After sulfuric acid exposure, a 5% compressive strength decrease occurred due to the presence of the functional groups of GO, hydroxylated MWCNTs, and small, low-density AgNPs on the surface of the cementitious composites. These results show that the impregnation method effectively improves cementitious composites' durability. Using PCA analysis, the pristine MWCNTs-blended cementitious composites were determined as the optimum specimen to obtain a durable mortar both pre- and post-acid exposure.

A review on the fresh properties, mechanical and durability performance of graphene-based cement composites

In real-world applications, composite materials based on cement that have excellent mechanical and durability properties are always preferred. The research establishment as a whole agrees that concrete, the most widely used building material in the world, must be produced at the nanoscale, where its chemical and physiochemical properties can be greatly enhanced. The microstructure of hydration gel has been reported in the current literature to be greatly improved by the high-surface volume ratio of nanomaterials, including carbon nanotubes (CNTs), nano silica, and nano alumina, which when used as additives in cementitious materials as strengthening additives. Recent advancements in materials science and nanotechnology have resulted in another promising nanomaterial, graphene, which may be employed as a nano-sized addition for concrete mixtures. In terms of mechanical and durability properties, cement matrix mixed with nanomaterials based on graphene performs significantly better due to a significant reduction of micro-cracks owing to its high surface area and tremendous ultimate tensile strength of graphene (130 GPa) and elastic modulus (1.1TPa). In this paper, recent research on graphene-based concrete was critically reviewed. By contrasting the fresh, mechanical, and durability qualities, the performance of cement composite is examined. Additionally, a thorough discussion of the strategies for improving the dispersion characteristics of graphene and its byproducts (edge-oxidized graphene, graphene oxide, and minimized graphene oxide) was conducted.The optimum dosages of graphene/graphene derivatives in concrete with respect to compressive, tensile, flexural strengths, and permeability were articulated with respect to the existing research works. The key obstacles and potential of graphene-based reinforced cement composites will be reviewed in order to give positive insights and suggestions for future investigations.

Performance characteristics of cementitious composites modified with silica fume: A systematic review

The intention of this study was to examine the use of the most prevalent industrial byproduct, silica fume, as a supplementary cementitious material (SCM). Along with the typical review, this study used the scientometric review technique to statistically examine the various features of the existing literature. A scientometric-based study can deal with the massive literature data using the applicable software tool. The bibliometric data on silica fume in concrete was gathered using the Scopus search engine between 2001 and July 2022. The top publication sources, co-occurrence of keywords, highly cited authors, and active contributing countries were all examined using scientometric analysis. Additionally, the properties of composites using silica fume as the SCM were discussed. The effect of silica fume addition on compressive, split-tensile, and flexural strength, as well as the durability and microstructure of cementitious composites, were described. It was concluded that the inclusion of silica fume as an SCM improved the material's properties while also providing environmental benefits. However, there is a limit beyond which silica fume addition showed an unfavorable effect on the performance of cementitious composites. The optimum proportion of silica fume in concrete was found to be in the range of 15–25 % by mass of cement. Moreover, literature data were utilized to develop prediction models for the strengths of cementitious composites containing silica fume, and the prediction models agreed with the actual results. These prediction models could be used to test the material strength, saving both time and cost.

Influence of mechanical treatment and magnetic separation on the performance of iron ore tailings as supplementary cementitious material

Despite the great importance of iron mining in the Brazilian economy, significant volumes of tailings with high iron content are generated in the ore beneficiation process. Even with high crystallinity, studies show that the iron ore tailings (IOT) can be used as a supplementary cementitious material (SCM). In this context, this work analyzes the influence of primary (PMT) and secondary (SMT) mechanical treatment and magnetic separation (MS) on the performance of IOT as SCM. To this end, the performance of cementitious composites (pastes and mortars for structural purposes) produced with and without 15% cement replacement by IOT under different treatment conditions was evaluated. The feasibility of reprocessing the iron-rich waste material (IRW) from MS was analyzed. The results showed that, even with SMT, the tailings did not show pozzolanic activity. The tailings with MS and SMT influenced the heat of hydration of the pastes, due to the greater nucleation effect, compared to the other tailings. For this sample, higher compressive strength was achieved among the samples with IOT. The IRW, when submitted to a flotation process, produced a material that still has economic viability.

A Study on the Healing Performance of Solid Capsules for Crack Self-Healing of Cementitious Composites

The purpose of this study is to investigate the healing performance of solid capsules made of cement as a basis for manufacturing self-healing capsules that can heal cracks in cementitious composites. The solid capsules were mixed with 5%, 10%, and 15% concentrations on the cement. The self-healing performance of cementitious composites with solid capsules was investigated through three evaluations. First, the mechanical strength-healing performance was evaluated through a re-loading test. Second, the durability-healing performance was evaluated through a permeability test. Finally, the crack-healing performance was examined by observing the crack widths. Through evaluation of the healing performance of the solid capsules, the healing performance of the compressive strength was found to be high when the capsule proportion was 10% and its size was within the range of 300 μm to 850 μm. Furthermore, the splitting tensile strength showed a high healing performance when the capsule proportion mixed was 15% and its size was 850 μm. In the case of the permeability test, a capsule size of 850 μm showed a healing effect greater than 95%. Cracks with a width of up to 200 μm tended to heal using capsules with a size of 600 μm to 850 μm.

The combined effect of carbon fiber and carbon nanotubes on the electrical and self-heating properties of cement composites

This work investigates the electrical and heating performance of conductive cement composites by using carbonaceous materials (carbon fibers (CF) and carbon nanotubes (CNT)) as conductive materials. Various volume fractions of carbonaceous materials were used to indicate the electrical heating performance of the cement composites. Experimental results showed that adding the carbonaceous materials in cement composites reduced the electrical resistance by more than 98% than that of the main cement paste. The percolation threshold of all carbonaceous cement composites was found to be between 0.1 and 0.75 vol%. By applying a potential voltage to the cement composites, different heating temperatures were investigated depending on the type of carbonaceous materials and their volume fractions. The conductive cement composites showed high heating performance exceeded 100°C within a record time when the input voltage is 60 V. At the end of the study, an analysis of electric power consumption was carried out to determine the feasibility of using carbonaceous materials as self-heating components in the suggested conductive cement composites.

Mechanical Properties of Cement Composites Using Modified Plastics by Gamma Irradiation

Recently, pollution caused by an increasing amount of worldwide plastic waste has become a global problem. However, these concerns can be alleviated by the use of gamma-ray technology. Using radiation technology, plastic wastes can be converted into a variety of useful purposes presenting powerful opportunities for environmental sustainability and material innovations. Plastics are strong, durable, waterproof, lightweight, easy to mold, and recyclable. In this study, plastic aggregate modified by gamma irradiation was mixed into cement composites, and mechanical property evaluation experiments were conducted. As a result, it was confirmed that the physical performance of cement composites was improved by up to 70% in the case of using the modified plastic aggregates compared to the general plastic aggregate.

Effects of nano-SiO2, nano-CaCO3 and nano-TiO2 on properties and microstructure of the high content calcium silicate phase cement (HCSC)

The performance of cement composites was significantly affected by clinker mineral component and nanomaterials. In this work, the effect of clinker mineral component and nanomaterials (nano-SiO2, nano-CaCO3, and nano-TiO2) on cement composites were investigated. Results illustrated that the optimal mineral compositions of C3S, C2S, C4AF, and C3A were 60.23%, 20.01%, 9.74%, and 10.02%, respectively. With the incorporation of nano-particles, the setting time of HCSC was shortened and strength was significantly enhanced, due to acceleration on hydration and optimization on microstructure. The CH content of HCSC containing nano-SiO2 was lower than that of reference due to pozzolanic activity at 28d, whereas the reversed results were found in the HCSC containing nano-CaCO3 and nano-TiO2 due to the nucleation effect promoting hydration. In addition, nano-particles increased mean silicate chain and Al/Si ratio of calcium-silicate-hydrate.

Effect of Wood Biomass Ash Storage on the Properties of Cement Composites.

Since ash from wood biomass mostly ends up in landfills, recent research has focused on finding its economic and environmental added value as a potential new raw material in the construction industry. However, for wood ash to be used on an industrial scale in construction, a strategy for its proper storage must be defined. Proper storage of WBA is important to ensure quality control for applications in cementitious composites. This work investigated the aging of wood biomass ash (WBA) collected from five different power plants in Croatia and its influence on the performance of cementitious composites. WBA and cement pastes were investigated at different aging times (up to one year) using thermogravimetric analysis (TGA), powder X-ray diffraction (XRD), isothermal calorimetry and initial and final setting times. The results showed that storage of WBA in closed and open containers resulted in carbonation and hydration of mainly free lime and periclase, respectively, which affected the reactivity and setting times of WBA cement pastes.

Recycling of raw water treatment sludge in cementitious composites: effects on heat evolution, compressive strength and microstructure

Water treatment sludge (WTS) is produced daily and represents a globally significant solid waste stream. The application of this sludge as construction materials has been studied although most studies have modified the sludge before its incorporation, hence involving significant energy consumption. This study aims to use raw sludge as a novel cementitious material, by determining the effects of sludge addition on the composition and performance of cementitious composites. Important aspects such as the physicochemical interaction of the raw sludge with the Portland cement, the heat evolution of the cement paste and the compressive strength of the composite cement were carefully studied. The results show that for 1-2% of WTS addition, the compressive strength and heat evolution of the cement paste was well maintained being close to the reference specimen after 28 days of curing. However, for sludge addition above 5%, a delay in the hydration reaction was observed, together with about 25% reduction in compressive strength at 28 days of curing. The mineralogical and thermal analysis showed decreasing portlandite content and increasing calcite in the WTS-amended composites. Scanning electron microscope analysis demonstrated that the addition of sludge induced more porous and weak surface structures compared to the reference specimen.

Study of the in-situ growth of carbon nanofibers on cement clinker

Because fibres are difficult to disperse evenly in cement-based materials, we attempted to grow carbon nanofibers (CNFs) in situ on Portland cement clinker particles using chemical vapor deposition (CVD). The results show that the phase compositions and alite polymorph didn’t change for the Portland cement clinker treated at 600 °C in the atmosphere of blended gas containing argon (Ar), hydrogen (H2) and acetylene (C2H2). The CNFs was successfully grown in situ on the Portland cement clinker due to the reaction of C2H2 in the presence of H2. The diameter and length of the CNFs were 20–30 nm and 0.6–0.9 μm respectively. C3S is the main component of cement clinker. The hydration of C3S plays a crucial role in the performance of cementitious composites. The hydration of C3S was significantly delayed and reduced due to the incorporation of CNFs.

Mechanical properties and durability performance of fly ash based mortar containing nano- and micro-silica additives

The aim of this paper is to investigate the influence of nano-silica (NS) and micro-silica (MS) on the properties of fly ash based geopolymer mortar. The use of such additives has the potential to provide greener and cheaper concrete with enhanced properties. A screening study was conducted to compare the performance of mortar containing varying percentages of NS and MS (up to 15%). The performance of each specimen was determined through tests on compressive strength, splitting tensile strength, workability, and water absorption. Results indicated that mortar with a dosage of 5% NS shows optimum results in workability and mechanical properties. This is mainly due to the pozzolanic and filling effects of large surface area nanosized particles on the cementitious matrix. Moreover, the effect of 5% NS was investigated for mortars containing different amounts of fly ash (up to 30%) which replaced cement by weight. With the presence of 5% NS, variation in fly ash content has no significant influence on the flowability. Although replacement of cement with fly ash at 10% in the presence of 5% NS decreased the splitting tensile strength, no significant reduction was noticed when compared with control samples (without nanoparticle). Compressive strengths also show significant reduction as the percentage of fly ash increases, however the presence of 5% NS aids in the strength development over 28 days. Observations from this study show the effects of nano-silica and fly ash dosage in the performance of cementitious composites. Thus, the results of this study is beneficial for future applications of nanomaterials in cement-based composites for generation of multifunctional construction materials.

Methodology for predicting the properties of cement composites at different scales

In order to meet new demands, the performance of cementitious composites needs to be altered scientifically, rather than on a trial-and-error basis. In this regard, a computational approach is proposed to predict the properties (modulus, strength and strain) of cementitious composites. The information from an analytical hydration model (at the lowest scale) is used for homogenisation and upscaled to obtain the properties of the cementitious composite. The proposed computational method has the unique characteristics of not only predicting the mechanical properties of the cement composite with reasonable accuracy, but is also able to trace how the properties evolve during the hydration process. The developed method is also extended to predict the strength and strain capacity of fibre incorporated cementitious composite. The analytically obtained results at each scale are validated through experimental investigations. The computational approach proposed and the findings of this study will assist the development of performance-based design of concrete composite.

Mechanical Performance of Cement Composites Reinforced with Raffia Palm Fabric

The utilization of plant based (natural) fabrics as reinforcement in composite materials is fast growing in the engineering field, due to their environmental friendliness and appreciable mechanical properties. This study was carried out to evaluate some flexural properties (flexural strength and flexural deflection) and water absorption rate of raffia palm fabric reinforced cement composite samples. Ordinary Portland cement (grade 42.5N) was used as the binding material. Cement to fine aggregate (450 µm) mix ratio of 1:3 (by weight) was employed for the composite production, while a water to cement ratio (w/c) of 0.4 was adopted. For the purpose of this study, cement composite beams were reinforced with raffia palm fabrics in 1-fabric, 2-fabrics and 2-layer configuration. All the cement composite samples were prepared and tested in accordance to ASTM standard procedures. Results from the flexural tests showed that the flexural properties of the composite samples were highly influenced by the raffia palm fabric reinforcement. The composite samples reinforced with 2- layers generally had higher flexural properties, when compared to the results obtained from the composite reinforced with 2-fabrics and 1 – fabrics reinforcement. The ultimate flexural deflection attained in the 2-fabrics and 2-layers configurations were comparable, but slightly highly in the 2-layers. A mean deflection of 6.12 mm was recorded in the composite reinforced with 2-layers, which was higher than the mean deflection of 5.56 mm recorded for the composite reinforced with 2-fabrics. For all cases, the unreinforced cement composite (control Samples) had the poorest flexural properties. In terms of the water absorption rate, the 2- layers fabrics composite samples had the highest water absorption rate when compared to the 1-layer fabric reinforced composite samples and the control samples. These results will be useful in the building industry and in the design and development of natural fabric reinforced concrete structures.

Performance of cementitious composites with nano PCMs and cellulose nano fibers

Nanotechnology is a promising technology that leads to very effective and efficient innovations in different disciplines. As it deals with substances on a nanoscale, it gives the opportunity to modify materials and obtain desired properties. In this study Phase Change Material (PCM) nano capsules are used to enhance the thermal properties of cellulose nano fiber (CNF). PCM/CNF nano composite insulator is developed and incorporated within cement mortar to enhance thermal properties of cement mortar. CNF is extracted from wheat straw by a chemo-mechanical method in the first part. The second part includes synthesis of PCM nano capsules using mini emulsion in situ polymerization method, and then PCM/CNF nano composite is prepared by encapsulated CNF within PCM nano capsules. The morphology, chemical, and thermal properties of CNF, nano capsules, and PCM/CNF nano composite are determined. Modified cement mortar is prepared by mixing different percentages of CNF, PCM nano capsules, and PCM/CNF nano composite with cement mortar. The thermal and mechanical properties of modified cement mortar are examined; the increase of thermal conductivity of cement mortar incorporated PCM/CNF nano composite is reduced in comparison with the addition of CNF alone. Regarding the compressive strength of cement mortar, the addition of CNF and PCM/CNF nano composite leads to increase compressive strength of cement mortar, where the greatest result is achieved with the addition of 0.5 wt%.