High Strength Cementitious Composites Research Articles

In‐situ compressive and tensile performances of high strength engineered cementitious composite at elevated temperatures

AbstractThe study provides novel insights on the compressive and tensile strength of high strength engineered cementitious composite (HSECC) at elevated temperatures under in‐situ testing condition. An optimized mix design was employed and cylinder and dogbone specimens were tested to study the compressive and tensile strength of HSECC at elevated temperature. The tested results under in‐situ test condition were compared with the residual state by exposing the specimens to temperature up to 600°C. It was found that specimens under in‐situ condition showed a drastic decrease in compressive strength (26.8%–34.5%) at 200°C and the performance was much inferior to that observed for residual state which showed only 12.2% decrease. This trend was consistent for both tensile and compression test results. After this, the in‐situ specimens underwent slight increase in the compressive strength with only around 25% decrease at 400°C and 14%–16% decrease at 600°C. However, the residual state specimens underwent continuous decrease in strength. Therefore, this study confirmed that for high strength cementitious composites exposed to elevated temperatures, the residual test results should not be considered as the lower limit and in‐situ testing results are essential for accurately predicting the behavior of cementitious composites. Thus, this research underscores the importance of conducting both in‐situ and residual state tests in the design of HSECC structural members.

Characteristics on compressive strength and microstructure of high-strength cementitious composites with waste glass beads

This study investigated the potential of waste glass beads (WGB), a recycled porous lightweight material derived from waste glass, to enhance long-term curing of moisture-saturated cementitious construction materials. The macroscopic properties and microstructure development of a cement composite material blended with two types of WGB––spherical (B) and crushed (CB)––were analyzed. The primary objective was to provide practical guidelines for optimizing WGB utilization as a moisture release medium and thus contribute to sustainable concrete production by exploring waste glass applications. This study demonstrated the potential of WGB for improving strength and void structure and could help enhance the long-term durability of cement composites. Valuable insights were gained regarding the surface roughness and specific surface areas alongside curing methods to maximize WGB's effectiveness. The key contributions are as follows: (1) varying effects on high-strength concrete (HSC) strength with increased WGB content and surface roughness and specific surface areas were analyzed; (2) a proportional relationship between closed pore volume and modulus affecting macroscopic properties was revealed; (3) insights into hydration product presence in the ITZ and its relationship with WGB moisture content were gained; and (4) notable improvements in indentation tests for specimens with WGB were achieved, indicating enhanced ITZ hydration and increased density within both ITZ and paste.

Performance evaluation of ternary blended cement concrete partially replacement of natural sand with granite quarry dust

Cementitious composites are the most frequently used man-made material, with a 25 billion tonne manufacturing volume and 5% greenhouse gas emissions. Concrete composites release a lot of CO2 into the environment. Thus, replacing concrete composite raw material is a priority. To reduce this industry's carbon footprint, large-scale reuse of industrial byproducts, including Fly Ash (FA), Silica Fume (SF), and Ground Granulated Blast-Furnace Slag (GGBS) in cementitious composites, is growing. This method addresses the waste management for industry byproducts in two ways. The mechanical strength and durability of cementitious composite products with many ingredients must be recognised. This study's major goal is to evaluate high-strength cementitious composites' mechanical strength and durability. FA (20%, 30%, and 40%), SF (5%, 7.5%, and 10%), and GGBS (10%, 15%, and 20%) binder were used to make high-strength cementitious composites. Waste management has developed into a problem for the environment. The illegal and unethical practices involved in mining natural river sand (NRS) have gotten worse. Therefore, by substituting Granite Quarry Dust (GQD) for fine aggregate, the lack of NRS for a building is prevented. GQD was employed to replace natural river sand at different levels of replacement as the fine aggregate phase in 10%, 20%, and 30%. The fresh cementitious composites properties were evaluated, strength properties such as compressive strength, flexural strength, and split tensile strength were also evaluated and additionally, the durability characteristics such as water sorptivity and the Rapid Chloride Permeability Test (RCPT). We shall evaluate it with normal concrete based on the results.

Graphene oxide-coated fly ash for high performance and low-carbon cementitious composites

Graphene oxide (GO) opens a new pathway for reducing carbon footprint in the construction industry and fabricating high-strength cementitious composites. However, due to the dispersion limitation, the application of GO in practical engineering has not been widely accepted. Hence, we evaluated the potential of the GO-fly ash hybrid as additives in cement under a coating method to assist the dispersion of the GO nanosheets. The results demonstrated that the GO could be successfully coated on the surface of the fly ash particles with good dispersion and strong connection via the proposed coating method. Besides, the coating method allowed more GO nanosheets to concentrate in the interfacial transition zone (ITZ) between fly ash and cement particles, making GO application more economical. The coated GO could then generate nucleation effects to promote the hydration process and provide pore-infilling effects to decrease the ITZ width (about 12.5%) and the crack ratio in ITZ (over 10%). Compared with the plain cement pastes, the workability, mechanical strength, and impermeability of the GO-coated fly ash modified cementitious slurry can be significantly reinforced up to 21.6%, 38.4% and 106.4%, respectively. The enhancement rate is further improved by about 7.1–58.5% compared with the traditional ultrasonic dispersion method. We expect the proposed innovative coating method would provide a good perspective of the future application of high-performance, cost-effective and environmentally friendly cementitious composites.

Verification of mechanism for effect of silane coupling agent modification of polyethylene (PE) fiber's surface on strain-hardening behavior of high-strength cementitious composites

To fully understand the mechanism for the effect of silane coupling agent (SCA) modified polyethylene (PE) fiber on the strain-hardening behavior of high-strength cementitious composites (HSCC), an experimental research has been conducted, including direct tension and microstructural tests using optical microscope, scanning electron microscope (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The results showed that, compare to the interfacial bonding between original PE fiber and very high strength matrix of cementitious composite at water/binder ratio (W/B) of 0.18, the interfacial bonding was strengthened after the modification of PE fiber's surface by SCA solution of 3% concentration, which subsequently resulted in the improvement of initial-cracking stress, ultimate tensile stress and ultimate tensile strain from 5.20 MPa, 6.34 MPa and 0.68% to 7.26 MPa, 8.01 MPa and 5.06%, respectively. The mechanism for the improvement in strain-hardening behavior of HSCC with SCA-modified PE fiber was that the physicochemical interactions occurred between the SCA-modified PE fiber and the matrix. Among these interactions, amino and hydroxyl groups connected to the PE fiber improved the hydrophilicity of fiber surface, which enhanced the physical bonding between the SCA-modified PE fiber and the matrix. More importantly, two types of chemical interactions have been proved to establish chemical bonding between the PE fiber and matrix, namely, the condensation reaction between hydroxyl groups of the modification layer on the PE fiber and hydroxyl groups of C–S–H gels in the matrix, and the combination of the polymer of SCA's hydrolysates with Ca(OH)2 released by cement hydration.

Impact of polyvinyl alcohol fiber on the full life-cycle shrinkage of cementitious composite

Engineered cementitious composite (ECC) enjoys huge potential in building structures thanks to its excellent tensile performance and energy absorption ability. However, free deformation of ECC deserves better understanding since large shrinkage strain usually induces internal tensile stress which would lead to cracking under constraint. Present study focuses on the full life-cycle shrinkage of polyvinyl alcohol (PVA) fiber reinforced ECC. Shrinkage and relative humidity (RH) at three water to cement (w/c) ratios were experimentally tested through novel integrated deformation measurement device. In contrast, plain mortars with the same w/c ratios were compared to evaluate the impact of PVA fiber on the over-time deformation and RH characteristics. Thereafter, shrinkage model considering fiber influence coefficient is established to simulate autogenous and drying shrinkage of PVA-ECC. Results show that full life-cycle shrinkage can be divided into two stages according to the internal RH measured. Distinct restraint effect of PVA fiber on both stages are observed. By comparing experimental and simulation results of PVA-ECC, the proposed fiber influence coefficient-based shrinkage model well illustrates the effect of PVA fiber, especially for high strength cementitious composites with relatively low w/c.

Compressive-Strength Analysis of High-Strength Cementitious Composites Mixed with Red and Green Pigments

We estimate the mechanical properties of pigment-containing ultra-high-strength cement composites (UHSCCs) and the pigment-induced changes in their physical properties via thermal and X-ray diffraction analyses. Hydrates in samples are analyzed using thermogravimetry. Additionally, the change in color expression with the UHSCC age is examined via the Commission Internationale de l’ Éclairage L*a*b* analysis. Correlation analysis is performed to determine linear relationships between experimental factors by calculating R2. A change in hydrate expression is confirmed as the strength increases with age. The pigment used affects the change in hydrate expression as well as color development. Correlation analysis of the results for all ages reveals that 5% red pigment mixing yields the highest R2 of 0.9858 in intensity-a*. The case of 10% red pigment mixing yields the lowest R2 of 0.5229 in intensity-b*. According to the amount of pigment used, we believe that quantitative results can be obtained by considering L* (contrast), rather than the relationship between intensity and color components. The appropriate mixing ratio based on the intensity expression of the red pigment is 3–8%, and the green pigment intensity and strength expression are inversely proportional. Our results can serve as a guideline for the performance development of pigmented cement-based composites.

Investigation of Mechanical and Durability Behaviour of High Strength Cementitious Composites Containing Natural Zeolite and Blast-furnace Slag

In this study, the changes in the mechanical and durability properties of the concrete mortar as a result of using artificial and natural pozzolanes (blast furnace slag (BFS), natural zeolite (Z) in clinoptilolite form respectively) in the production of concrete mortar separately or together as a replacement material were investigated. For this purpose, Z and BFS were used partially replace Portland cement at 5%,10%, 15% and 20% by weight. Flow table, compressive strength, drying shrinkage, abrassion resistance experiments, rapid chlorine permeability experiments and microstructural analysis were carried out for prepared samples. According to the results, optimum dosages of the puzzolans were found 20% for grounded blast furnace slag, 10% for natural zeolite and %20 for concrete mortar containing both 10% grounded blast furnace slag and 10% natural zeolite as substitution materials. It is concluded that these pozzolan substituted in the mortar at these rates improve some properties of the mortar in the best way. In general, the aim of the study is to reduce cement production and to recycle waste products, which have a great impact on the environment.

Influence of Steel Fiber Addition on the Vibrational Characteristic of High Strength Cementitious Composites

Structural materials and their properties in different applications with next-generation composite production techniques are quite promising areas. In this study, new composite blocks were produced with the addition of industrial and recycled steel fibers to high strength cementitious composites (HSCCs). The vibrational damping capabilities of the blocks produced in standard dimensions (16 cm × 4 cm × 4 cm) were tested by using the modal analysis method. In many different applications, structural materials are expected to absorb vibrations such as earthquakes or artificial vibrations from machine systems operating in industrial areas. In this study, the vibration damping capability of HSCCs was investigated and improved by adding steel fiber to HSCCs. The experimental study shows that adding steel fibers improves the bending stress by up to 127% and damping ratio over 200%. The fiber size and distribution play a significant role in this improvement. This effect was also achieved to a certain extent in the samples produced using recycled steel fibers obtained from waste tires. In this way, the vibration damping ability of the HSCCs is increased with an environmentally friendly approach.

Performance of High Strength Cementitious Composites with High Volume Supplementary Cementitious Materials

Portland cement (PC) is the major binder used for cementitious composites. However, due to the increase in the demand for cementitious composites for the construction of infrastructures, there’s a consequential effect of the production of this binder (i.e. PC) on the sustainability of our environment. The production of PC emits huge amounts of carbon dioxide into the environment and posses a huge strain on the natural deposits of its raw material. In order to create a sustainable environment while meeting the high demand for cementitious composites; it is paramount to replace the PC with locally available waste materials. This study incorporates a high volume of slag alongside silica fume at a ratio of 2.2 to that of PC to produce high strength cementitious composites. The effects of these compositions were determined experimentally on its fresh and hardened properties. Results from this study showed that high strength cementitious composites can be produced with a high volume of supplementary cementitious composites up to 80%. The use of slag as 80% replacement of slag resulted in a 9.3% increase in the compressive strength and a 48.1% decrease in sorption.

Experimental Investigation of Mechanical and Dynamic Impact Properties of High Strength Cementitious Composite Containing Micro Steel and PP Fibers

Cementitious composites are one of the most consumed construction materials in the world. The use of cementitious composites is increasing due to their special characteristics. The behavior of high strength cementitious composites is improved by increasing the fiber percentage. In the present paper, the effects of steel microfibers and polypropylene fibers on mechanical properties and impact resistance of high strength cementitious composites are investigated. The percentage of fibers used in the study was 0, 0.5, and 1.5% in seven separate and three combined mix designs. Experiments were carried out on 120 specimens in 10 mix designs. Compressive strength, tensile strength, flexural strength, and dynamic impact tests were carried out on 10 mix designs manufactured in this research. The dynamic impact strength of the disc specimen was investigated by a drop hammer test machine with a capacity of 7500J. After testing the samples, it was shown that using a high percentage of steel and polypropylene fibers reduces the compressive strength and increases tensile strength, flexural strength, and impact strength. The effects of steel microfibers on the reduction of the crush displacement resulting from the dynamic impact were higher than that of polypropylene fibers.

Effect of Inorganic SiO2 Nanofibers in High Strength Cementitious Composites

The paper deals with the verification of the effect of the addition of inorganic SiO2 nanofibers to cement composites. In the first stage, a stable suspension of SiO2 nanofibers was prepared in an aqueous medium. It is important to distribute nanofibers so that the nanofibers do not appear in the form of clumps and at the same time do not get damaged during the dispersion process. The ultrasonification process was used for dispersion. The dispersed suspension of SiO2 nanofibers and water was dosed together with the superplasticizing admixtures into the dry components of the cement composite and the components were homogenized. The properties of the cement composite with SiO2 nanofibers have been tested – compressive strength, flexural strength, density. Composites with the addition of SiO2 nanofibers at a dose of 0.008 % by weight of cement exhibited an increased compressive strength of up to 33 % and a 19 % greater flexural strength at doses of 0.016 and 0.032 % of cement weight than the reference sample without nanofibers. The presence of SiO2 nanofibers in the composite was monitored by scanning electron microscopy (SEM).

The mechanical strength and durability properties of ternary blended cementitious composites containing granite quarry dust (GQD) as natural sand replacement

Cementitious composites are the most used man-made materials in the world with a global annual production quantum of 25 billion tonnes worldwide, contributing approximately 5% to the global greenhouse gas emissions. In the initiative to reduce the carbon footprint of cementitious composite production, are growing interests in the large volume reuse of industrial by products such as ground granulated blast-furnace slag (GGBS), pulverized fuel ash (PFA) and granite quarry dust (GQD) in cementitious composites production. Such an approach offers a two-fold solution towards addressing the waste management problem related to those industry by-products. At the same time however; reduction of carbon footprints of cementitious composite materials exists. However, in order to enable scalable applications of such a recycling approach, a comprehensive body of knowledge on the mechanical strength and durability performance of the cementitious composite products containing a large volume of the materials needs to be established. Hence, it is the primary aim of the study to report a comprehensive assessment on the mechanical strength and durability properties of high strength cementitious composites. These materials are produced with a large volume of the aforementioned materials as the primary binder and aggregate phase. Throughout the investigation, high strength cementitious composites mixes were produced with a large volume of PFA and GGBS binder. Then phase coupled with ordinary Portland cement (OPC). GQD was used as the fine aggregate phase in substitution of natural river sand at various level of substitution ranging between 0 and 100% by volume. The cementitious composites were characterized in terms of its fresh cementitious composites. Its flowability and hardened cementitious composites properties mainly bulk density, compressive strength, flexural strength, and Ultrasonic Pulse Velocity were also assessed. In addition, the durability properties such as water absorptivity and porosity were also covered in this experimental program. Pore continuity was assessed in terms of air permeability and capillary absorption of the hardened specimens according to the testing age. This paper has also covered the dimensional stability assessment in terms of drying shrinkage. Besides, a comprehensive microstructural assessment was also performed to examine the microstructure morphology. From the results, we found full incorporation of GQD as NRS without significant impairment to the mechanical, durability and length change performance. Thus, the production of sustainable high strength cementitious composites with large volume recycling of GQD is feasible which in turn reduces the depletion on the natural river sand resources.

A comparison of the effects of pozzolanic binders on the hardened-state properties of high-strength cementitious composites reinforced with waste tire fibers

Experimental and statistical analyses were conducted to examine the effects of partially replacing ordinary Portland cement (OPC) with pozzolanic binders (silica fume and fly ash) on the hardened-state characteristics of high-strength cementitious concrete reinforced with steel fibers recovered from waste tires. The variables used in the analyses were the concentration of recycled steel fibers (volume fraction = 0.5% and 1%) and the proportion of silica fume or fly ash used to replace OPC (weight = 10%, 20%, and 40%). The effects of combining fibers at two volume fractions with pozzolanic binders in 14 mixtures were investigated through an experimental program carried out in two stages. First, the effects of replacing OPC with silica fume or fly ash on the matrix were determined by assessing the heat of hydration, the formation of the crystalline phases using X-ray diffraction analysis, the gel structure and mass loss at elevated temperatures with thermogravimetric, and differential thermogravimetry analyses, and porosity structures of pastes with using the mercury intrusion porosimetry test. Second, the effects of adding recycled steel fibers on the hardened-state properties of OPC-based concretes containing pozzolans were explored by evaluating the water absorption by immersion and capillary rise, ultrasonic pulse velocity, compressive strength, splitting tensile strength, flexural strength, and impact resistance of the reinforced mixtures. The experimental results were subjected to linear regression and statistical analysis to correlate the mechanical and impact properties of the mixtures and identify probability distributions, respectively.The findings showed that using pozzolanic binders enhanced the mechanical and impact properties of the mixtures reinforced with fibers from waste tires, thereby affecting the fibers’ frictional pull-out behavior. Therefore, significant differences on the impacts of fiber content were found on the post-peak responses of the mixtures under flexural loading. In general, using silica fume had higher impact on enhancing the hardened-state characterizations than fly ash. The greatest enhancement in mechanical properties was observed when OPC was replaced with 40% silica fume.The analytical results confirmed that silica fume was better fitted to the normal distribution than fly ash, while fly ash produced a higher coefficient of correlation between mechanical and impact resistance than did silica fume.

Modern High Strength Concrete with Unique Properties

Artificial stone has been one of the most common materials in construction for a long time by now. Despite the variety of types of concrete, the composite is in constant motion of development and improvement. The common use of high strength composite is for the construction of high-rise buildings or projects complex in geometry.This article suggests preparing high-strength cementitious composites by complex chemical activation using chemical admixtures in combination with reactive aggregates, as they give good hydration (hardening) of concrete. Research results confirm that this practice of complex chemical activation of cement gives high-strength concrete with better strength, deformation and durability properties.

Flexural Performance and Reflective Cracking Behavior of Repair Systems Produced with High Early Strength Cementitious Composites

Çalışma kapsamında, yüksek süneklilik ve çekme yüklemeleri altında sergilenen çoklu dar çatlak genişlikleri özelliklerinden ödün vermeden erken yaş yüksek dayanımlı ve onarılacak beton ile en yüksek derecede bağ kuracak yeni nesil onarım malzemeleri tasarlanmış ve bu malzemelerin performansı piyasada yaygın olarak kullanılan bir başka onarım malzemesiyle karşılaştırılmıştır. Çalışmanın birinci bölümünde monolitik halde test edilen karışımların temel mekanik özellikleri değerlendirilmiştir. İkinci bölümde ise tabakalı olarak hazırlanan karışımların onarım malzemesi olarak kullanılabilirlikleri eğilme performansı ve yansıma çatlağı davranışları göz önünde bulundurularak değerlendirilmiştir. Çalışma kapsamında üretilen HESECC karışımlarının tamamı literatürde bir onarım malzemesinden erken yaşta beklenen temel mekanik özelliklerin tamamını fazlasıyla karşılamış ve üretilen tabakalı numuneler, piyasada yaygın bir şekilde kullanılan OM numunelerine kıyasla çok daha sünek bir davranış sergileyerek yansıma çatlağının yayılımını önemli ölçüde azaltmıştır.

Shrinkage of internal cured high strength engineered cementitious composite with pre-wetted sand-like zeolite

In this paper, shrinkage and internal relative humidity of internal cured with calcinated zeolite particles of high strength engineerined cementitious composite (HSECC) are experimentally investigated, in which the natural sand-like zeolite particles with average particle size of 0.18mm were used as internal curing agent. Impacting factors, such as calcination, pre-wetting process and amount of internal curing agent, on shrinkage of HSECC were considered in the test program; meanwhile their effects on compressive strength of the composites were included as well. The test results show: 1) Two-stage progressing mode of shrinkage and internal relative humidity of HSECC are observed; 2) Applying the pre-wetted calcined zeolite particles in HSECC, more than 60% of autogenous and/or drying shrinkage at 28days is reduced while the strength of the composite remains as higher as the reference; 3) Calcination on zeolite particles is necessary for internal curing of high strength cementitious composites.

Nanotechnology and construction: use of nanoindentation measurements to predict macroscale elastic properties of high strength cementitious composites

This paper aims to present the experimental results involving the use of nanoindentation measurements and prediction of macroscale elastic properties of high performance cementitious composites (HPCC). The elastic properties of HPCC mixture were evaluated at different length scales by nanoindentation (microscale), and elastic moduli and compressive strength tests (macroscale). The nanoindentation results, obtained by grid indentation with subsequent phase deconvolution, were complemented by an independent porosimetry test and inserted into a two-step analytical homogenization scheme to predict the overall macroscale properties. The final results show that the presented method allows a reliable advanced prediction of HPCC elastic properties indicating, thus, that inserting nanotechnology in the concrete industry can be promising, since it would allow the production of a more predictable composite in an easier and less expensive way.

Direct Tensile Tests on Concretelike Materials: Structural and Constitutive Behaviors

The complete stress-strain and stress-crack opening response of a concretelike material loaded in tension is examined starting from a series of displacement-controlled tests on notched cylinders, whose end sections were prevented from rotating (fixed platens). The test results refer to two very high-strength cementitious composites (tensile strength fc ≈ 160–165 MPa) and one “reference” high-strength concrete (fc ≈ 90 MPa). Their behavior (pseudoelastic up to first cracking and cohesive after crack localization) is analyzed to identify the nonlinear stress-strain and stress-crack opening response and to distinguish it from the structural behavior of the specimens. The ascending branch is modeled by studying the stresses at the notch tip by means of Neuber's approach based on stress concentration factors. As for concrete softening (falling branch), an appropriate cohesive law is introduced. Finally, the structural response associated with progressive cracking is systematically analyzed, and once more, it is shown that the load-displacement relationship obtained in a test is hardly a material property.

Mechanical properties and pore structure of carbon fiber reinforced cementitious composites

The development of high strength cementitious composites by the use of silica fume, together with the development of high performance synthetic fibers, open the way to the production of new cementitious composites of superior performance. The purpose of the present research was to study the performance of dense cement-silica fume matrices reinforced with high performance PAN type carbon fibers, in order to determine the influence of matrix composition on the characteristics of the composite. Special attention was given to the short term mechanical properties (flexural strength and toughness), and the internal pore structure. Composites with water to binder ratio of 0.40 and silica-fume (SF) content of 0% to 28% were tested at the ages of 1,3 and 28 days. Test results indicate that at the early age of one day, the mechanical properties increase with the increase in the SF contents, while the internal structure remains quite the same. At 28 days the mechanical properties increase with the addition of SF up to a maximum at 7%, and decrease with higher content of SF. The internal pore structure, however, becomes finer as the SF content increases.