Portland Cement Composites Research Articles

Impacts of nano C-S-H-PCE on durability-related properties of Portland cement composites with high-volume GGBFS

Replacing Portland cement (PC) with high-volume ground granulated blast furnace slag (GGBFS) reduces carbon emissions but decreases the early strength of PC materials. Although using nano-calcium silicate hydrate (n-C-S-H) has been demonstrated to enhance the early strength of high-volume GGBFS-blended cement (HVGBC), its effects on durability still needs further research. This study investigates the impacts of n-C-S-H-polycarboxylate (PCE) composites on the properties of HVGBC-based materials, including compressive strength, anti-chloride permeability, and carbonation resistance, as well as the pore structure characterized using Mercury Intrusion Porosimetry (MIP) and X-ray Computed Tomography (CT). The results indicated that using n-C-S-H-PCE remarkably elevated the compressive strength of PC with 50 wt% GGBFS within 7 d of curing. Adding 1 wt% n-C-S-H-PCE increased the hydration degree of PC and GGBFS and significantly improved the resistance of the mortar to chloride penetration and carbonation compared with those of the pure PC mortar. MIP and 3D visualization by CT revealed that using an appropriate amount of n-C-S-H-PCE formed a dense microstructure, thus improving the early strength and durability. This work gives some insights into using the effective addition of n-C-S-H-PCE to dramatically elevate the early mechanical properties of HVGBC composites while maintaining their excellent durability.

Microstructure analysis of cement-biochar composites

The use of biochar as a concrete constituent has been proposed to reduce the massive carbon footprint of concrete. Due to the low density and complex porosity of biochar, microstructural analysis of Portland cement-biochar composites is challenging. This causes challenges to the improvement of the micro-scale understanding of biochar composite behavior. This work advances the microstructural understanding of Portland cement composites with 0, 5, and 25 volume percent (vol%) of cement replaced with wood biochar by applying common characterization techniques of mercury intrusion porosimetry (MIP), gas sorption, scanning electron microscopy, and isothermal heat flow calorimetry (HFC) in conjunction with 1H nuclear magnetic resonance (NMR) and micro-X-ray computed tomography (XCT) analysis techniques. The combination of these techniques allows a multi-scale investigation of the effect of biochar on the microstructure of cement paste. NMR and XCT techniques allow the observation and quantification of the pore space. HFC and MIP confirmed that biochar absorbs moisture and reduces the effective water-cement ratio. Gas sorption, MIP, and NMR shows that 5 vol% replacement does not significantly affect the gel and capillary pore structures. Results from XCT (supported by MIP and NMR) show that biochar can reduce the formation of larger pores. Importantly, XCT results suggest that biochar can act as a flaw in the microstructure which could explain reductions in the mechanical properties. Overall, the mechanical properties already analyzed in the literature are consistent with the microstructural changes observed, and these results highlight the need to carefully tailor the volume fraction of biochar to control its effect on the paste microstructure.

Mechanical Response and Anti-Reflective Crack Design in New Asphalt Overlays on Existing Asphalt Overlaying Composite Portland Cement Pavement

A detection and evaluation system containing a two-level index of structural integrity and bearing capacity was constructed based on ground-penetrating radar (GPR) and a falling weight deflector (FWD). This system was constructed to solve problems with the detection, evaluation, and structural and material design of asphalt rehabilitation for the prevention and control of asphalt reflection cracks in asphalt overlaying composite Portland cement pavement. Based on the detected data from the GPR and FWD, the reasonable and recommended thickness range of the stress-absorbing layer was determined by the finite element method, and the optimization design of an anti-reflective crack structure is proposed. Furthermore, a material design and engineering application of the stress-absorbing layer was carried out. The results show that an additional 10 cm layer of repaved asphalt can reduce temperature stress by 64.1%, reduce fatigue stress by 29.3% at the cement slab bottom, and extend the service life by 23.1 years. The reasonable thickness of the stress-absorbing layer ranges from 1.6 cm to 2.0 cm, and the recommended structural combination design is a 4 cm SMA-13 upper layer, a 4 cm AC-16 lower layer, and a 2 cm stress-absorbing layer overlaying existing asphalt overlay. The impact toughness of the designed stress-absorbing layer is 1.05 times and 1.44 times that of the other stress-absorbing layer and the AC-16 asphalt mixture, respectively, which have been successfully used for more than 5 years. The recommended design rehabilitation has good engineering application. The uniformity of the stress-absorbing layer can reach 63%, and an anti-reflective crack effect is expected. The results of this study provide design methodology and experience for composite pavement repaving.

Silica Quartz Characteristics from Local Silica Sand on Compressive Strength of Mortar

Many minerals, including quartz sand, granite, and feldspar, contain silica (SiO2), a substance that performs the same function as quartz. Silicate (SiO2), the primary mineral found in silica sand, can be added to concrete mixtures to boost strength. This means that silica sand can be employed as a cementitious component in concrete because it is believed to have pozzolanic and amorphous qualities. This study is part of a series that tries to use silica sand from an area in Indonesia. The purpose of this research was to manufacture and describe quartz silica (QS) from Kolaka silica sand, which was acquired from Southeast Sulawesi province in eastern Indonesia. In order to improve the characteristics of mortar mixtures that use composite Portland cement as a binder, it is advised to combine the X-ray diffraction process with an evaluation of the impact of addition (QS) on their physical and mechanical properties (volume weight and compressive strength). Laboratory experimentation is being conducted here. Water, cement, and silica sand are used to make mortar specimens. Red and white silica sand is the type of silica utilized. The specimens were created with a 50 mm diameter and a 100 mm height. Tests on mortar's compressive strength were performed after 7, 14, and 28 days. The study's findings indicated that the amounts of quartz formed in red and white silica sand were 45.05% and 91.87%, respectively. The volume weight that results is approximately 2.78 gr/cm3. Red silica sand was tested for compressive strength at ages 7, 14, and 28 days, and the findings were 20.73, 23.32, and 24.61 MPa, respectively. White silica sand has compressive strengths of 21.83, 24.67, and 26.52 MPa. We are aware of no prior studies examining the use of crystalline silica from Kolaka silica sand to enhance the mechanical qualities of cement mortar. Doi: 10.28991/CEJ-2024-010-08-010 Full Text: PDF

Community Assistance in the utilization of Nickel Slag in the Morosi Village

Morosi Village located in Konawe Regency is one of the areas in which there is a nickel processing company. The nickel processing produces solid waste, one of which is nickel slag. The amount of nickel slag is accumulating day by day, because each process of refining one ton of nickel product produces 50 times the solid waste, equivalent to 50 tons. So that from the results of quite a lot of waste, research was carried out to use solid waste as a concrete forming material, either as coarse and fine aggregate, or as a cement mixture. Government Regulation No. 101 of 2014 classifies nickel slag as B3 waste hazard category 2 with waste code B403. This means that nickel slag is a waste that has a delayed effect, and has an indirect impact on humans and the environment. Meanwhile, at the end of 2019, the Indonesian National Standard (SNI) concerning the choice of nickel slag material from electric furnaces. This SNI was also prepared by the Ministry of Industry to support the development of nickel slag standards and as a solution for nickel slag management. The existence of SNI is also intended as a reference to optimize the use of nickel slag as aggregate, substitute for natural aggregate and other uses. Some examples of products made from nickel slag include bricks, precast and ready-to-print concrete, road base and field, soil improvers, growing media and fertilizers, mortar and cement slag, composite portland cement, and cement geopolymers. To accommodate the use of nickel slag, assistance is needed to the community, especially in Morosi Village to be able to process with appropriate, effective and efficient technology in accordance with its physical characteristics and chemical characteristics. This will be an alternative to reduce the amount of nickel slag that can pollute the environment, in addition to increasing people's income.

Perspective of concrete with Portland composite cement CEM II/C-M (S-LL)

Perspective of concrete with Portland composite cement CEM II/C-M (S-LL)

Influence of iron content of chemically and mineralogically modified electric arc furnace slag on the hydration and environmental behaviour of composite cements

This work investigates the influence of the iron content of tailored electric arc furnace slag (EAFS) on hydration and strength development as well as associated heavy metal leaching properties of Portland composite cement. Further, the impact of limestone additions was investigated. EAFS from scrap smelting plant was used as starting material. Tailored EAFS was produced by re-melting, conditioning, and water quenching. By that, a glassy material with defined chemistry was obtained. The tailored EAFS strongly contributed to the compressive strength development between 7 and 28 days. Composite cements containing 35 wt.-% EAFS reached an activity index above 85 % after 28 days. The addition of limestone and amine-based quality improvers resulted in an increase of the reached compressive strength at all tested ages. That is linked to the accelerated and increased AFm phase formation. This effect is more pronounced for EAFS with high iron content. Contrary, C-S-H formation was promoted if EAFS with low iron content was used. Chromium leaching was not critical despite the high content in the tailored EAFS. The lowest vanadium leaching was observed for EAFS with low iron content.

Impact of Pernicious Chemicals on Geopolymer and Alkali-Activated Composites Incorporated with Different Fiber Types: A Review

Over the past decade, developing geopolymer mixes to replace ordinary Portland Cement (OPC) composites has yielded positive results, leading to extensive research. The incorporation of fibers in geopolymers, besides impacting the mechanical properties, has also significantly impacted durability, mainly when dealing with the most pernicious forms of deterioration resulting from chloride attack, water penetration, sulfate attack, acid attack, as well as freeze-thaw, which occurred through chemical transgression. This study presents a systematic approach to thoroughly review the durability properties of fibrous geopolymer composites exposed to harmful chemicals and extreme environmental conditions. The multi-parameters and factors critically influencing fibrous geopolymers' physical and chemical stability are examined. The study is further aimed at providing an update on the research work undertaken to assess the impact of fiber incorporation on the durability of geopolymer and alkali-activated composites thus far. Furthermore, this review hopes to promote and facilitate research on durability for the long-term, large-scale adoption, and commercialization of advanced fibrous, non-OPC-based materials.

Effect of nano-silica on the flexural behavior and mechanical properties of self-compacted high-performance concrete (SCHPC) produced by cement CEM II/A-P (experimental and numerical study)

The extensive use of cement exacerbates the greenhouse effect by increasing carbon dioxide (CO2) emissions. So, many standards recommend using Portland-composite cement in construction as one of the methods for reducing CO2 emissions, especially cement CEM II/A-P. This paper presents an extensive experimental and numerical study to investigate the effect of micro and nano-silica on the flexural behavior and mechanical properties of Self-Compacted High-Performance Concrete (SCHPC) produced by cement CEM II/A-P. The extensive experimental work consisted of eight mixtures: three with micro-silica (MS), four with nano-silica (NS), and a reference mixture without silica. For both MS and NS, different percentages of adding or replacement content were tested to study their effect on the following: (a) the workability of fresh concrete, (b) concrete compressive strength, (c) splitting tensile strength, (d) flexural behavior including flexural tensile strength, and (e) the optimum percentage of each of the MS and NS to get the maximum structural and economic benefits of using for SCHPC with CEM II/A-P. Also, through a statistical program, these experimental results were used to obtain accurate formulae that could predict both the splitting tensile strength (fsp) and modulus of rupture (fctr) for SCHPC with adding nano-silica. In addition, the numerical study verified the experimental results based on the finite element program ANSYS. The flexure behavior of SCHPC beams is verified using the Microplane model (recently added to ANSYS). The experimental results showed that adding NS is more effective than replacing or adding MS for SCHPC mixture with CEM II/A-P to increase the concrete compressive strength, splitting tensile strength, and flexural tensile strength, especially for the mixture with adding NS content of 4 %. The numerical results showed the ability of the coupled damage-plasticity microplane model to simulate the flexural behavior of the tested SCHPC beams with MS or NS well. This research confirms nano-silica's structural and economical efficiency in the behavior of SCHPC beams. It was found that the optimum percentage of adding NS is 4 % for SCHPC mixtures with CEM II/A-P.

Study on pore structure and acoustic emission characteristics of Mg(OH)2 modified expired cement

This study investigated the preparation of cementitious mortar specimens (ECM) by blending different dosages of pure magnesium hydroxide (AR), active magnesium oxide, and nano magnesium hydroxide as external additives with expired composite Portland cement. The optimal solution was selected by comparing their “nuclear magnetic resonance” (NMR), mechanical properties, and acoustic emission characteristics. NMR experiments revealed that the addition of 4 wt% nano magnesium hydroxide to expired cement resulted in the largest decrease in harmful pore content in ECM, reaching 21.9%. Mechanical performance testing and acoustic emission monitoring results indicated that the strength of ECM reached a maximum of 21.356 MPa with the addition of 4 wt% nano magnesium hydroxide, representing a 20.2% increase compared to the control group. This suggests that adding 4 wt% nano magnesium hydroxide to expired cement is a preferable option.

Mechanical Properties and Durability of Composite Cement Pastes Containing Phase-Change Materials and Nanosilica.

Escalating global surface temperatures are highlighting the urgent need for energy-saving solutions. Phase-change materials (PCMs) have emerged as a promising avenue for enhancing thermal comfort in the construction sector. This study assessed the impact of incorporating PCMs ranging from 1% to 10% by mass into composite Portland cement partially replaced by fly ash (FA) and nanosilica particles (NS). Mechanical and electrochemical techniques were utilized to evaluate composite cements. The results indicate that the presence of PCMs delayed cement hydration, acting as a filler without chemically interacting within the composite. The combination of FA and PCMs reduced compressive strength at early ages, while thermal conductivity decreased after 90 days due to the melting point and the latent heat of PCMs. Samples with FA and NS showed a significant reduction in the CO2 penetration, attributed to their pozzolanic and microfiller effects, as well as reduced water absorption due to the non-absorptive nature of PCMs. Nitrogen physisorption confirmed structural changes in the cement matrix. Additionally, electrical resistivity and thermal behavior assessments revealed that PCM-containing samples could reduce temperatures by an average of 4 °C. This suggested that PCMs could be a viable alternative for materials with thermal insulation capacity, thereby contributing to energy efficiency in the construction sector.

Strength, Microstructure, and Life Cycle Assessment of Silicomanganese Fume, Silica Fume, and Portland Cement Composites Designed Using Taguchi Method

Strength, Microstructure, and Life Cycle Assessment of Silicomanganese Fume, Silica Fume, and Portland Cement Composites Designed Using Taguchi Method

APPLICABILITY OF BITUMINOUS-BASED INHIBITOR AS CORROSION PREVENTION METHOD IN REINFORCED CONCRETE

Corrosion is the most common cause of structural and material degradation in reinforced concrete (RC) constructions. A well-constructed structure protects the embedded steel bar from chloride ions both physically and chemically, which is particularly important for constructions exposed to seawater. Given the significant economic losses caused by corrosion, suitable measures to reduce corrosion in concrete are required. In this study, three-layer of bituminous-based inhibitor was applied to the surface of two steel bars embedded (steel coating) in mortar cement with 3 cm and 5 cm of concrete cover. Portland composite cement (PCC) and Portland pozzolan cement (PPC) was used as a binder material of mortar cement. The cubical mortar cement specimens were fabricated, and exposed to three conditions (e.g., wet condition, dry condition, and dry-wet cycle) until 60 days after 28 days of immersed water curing. The results demonstrated that corrosion prevention employing steel coating techniques by using bituminous-based inhibitor gives superior protection as seen by a higher positive corrosion potential value when compared to non-coating specimens, implying that the coating method may be used to prevent corrosion. This is because the coating process by using bituminous-based inhibitor may prevent ions from entering the reinforcing steel. In all exposure circumstances and with all preventive procedures, a concrete cover with a thickness of 5 cm has a lower corrosion risk, as shown by a higher corrosion potential value, than a concrete cover with a thickness of 3 cm. The larger the thickness of the concrete cover, the more the surrounding ecosystem is protected. The utilization of PPC as binder in concrete maintained the stable corrosion potential value when the coating method applied.

Environmental and technical assessment on the application of slate waste in Portland-composite cement CEM II

Large volumes of waste are generated from the manufacture of slabs, roofing, and tiles using slate stone. The use of waste in the construction industry is prevalent due to the environmental advantages associated with the implementation of circular economy standards. This paper examines the production of Portland cement CEM II using heat-treated slate waste. The fineness index results were 10.95 % for the 75-μm sieve and 23.53 % for the 45-μm sieve. Assessment of reactivity using mechanical methods showed that mortars produced with 20 % slate waste (SW) achieved a strength of 42.35 MPa and a mechanical index of 84.93 %. Direct measurement (FTIR), along with chemical methods (Frattini Test and Saturated lime test), confirm the pozzolanic activity of the slate waste. The environmental impact assessment demonstrated a reduction in the carbon dioxide emission rate by 21.49 % (6.54E+02 kgCO2-eq/t) with the use of Portland cement CEM II/CSW. The valorization of slate waste can contribute to the availability of an alternative source of raw material and the reduction of natural resource consumption. However, further studies on mechanical performance and durability are necessary for this waste to be applied in structural cementitious matrices.

Sensing mechanisms of nanomodified Portland cement composites

Mortar sensors were fabricated as beams incorporating different amounts of carbon nanofibers (CNFs) synthesized in-situ on cement particles. Changes in electrical resistivity were measured and compared to recorded changes in compressive stress, temperature, and humidity. Sensing mechanisms and corresponding models were developed. The findings of the study indicate that the piezoresistive effect is influenced by the critical concentration of CNFs inside the composite matrix and the tunneling effect. In addition, water absorption and desorption, as well as the amount of chemically bound water played an important role in humidity sensing. Thermal fluctuation-induced tunneling conduction was dominant for the temperature sensitivity.

Microstructural Assessment of Pozzolanic Activity of Ilmenite Mud Waste Compared to Fly Ash in Cement Composites.

This paper presents the influence of adding rinsed ilmenite mud waste (R-MUD) on the microstructure of Portland cement composites, compared to similar composites containing fly ash (FA). The aim of the study is the assessment of the pozzolanic activity of ilmenite mud waste by its impact on the microstructure of the cement matrix in comparison to the undoubted pozzolanic activity of fly ash. The presented test results include pore size distribution, phase composition, pozzolanic activity using thermal analysis, R3 bound water test, and microstructural analysis using scanning electron microscopy (SEM). Tests were performed on mortars cured for up to 360 days. The results presented in this paper have shown that R-MUD has a pozzolanic activity level similar to FA or better, which influences pore size distribution in the composite and its microstructure. During the curing process, the microstructure of composites containing R-MUD became more compact and sealed than those with FA, which might also increase their durability. The results of the R3 tests have proven the pozzolanic activity of R-MUD but its level was lower than FA. R-MUD might be a useful substitute for fly ash, especially given the lack of good-quality fly ash on the market.

INVESTIGATION OF STEEL ANGLE AND PLATE CONFINEMENT ON CONCRETE UNDER AXIAL LOAD USING DIFFERENT AGGREGATE

Steel and concrete are frequently used to construct composite structures, making steel-concrete composites the most common choice. This research aims to compare the confinement effects observed in stone aggregate, brick aggregate, and recycled brick concrete. This analysis evaluates the impact of various thicknesses of steel angles (3mm and 4mm) and steel plates (3mm and 4mm) on the confinement effect. Each aggregate is studied using 18 cube specimens: six with 3mm steel angle confinement, six with 4mm steel angle confinement, and six without steel angle and plate confinement. This study employed Portland Composite Cement and coarse sand at 1:2:4 and 0.45 water-cement ratios. The concrete is carefully built to meet specifications and retain the slump value. Compressive strength testing is conducted on the concrete specimens at the 28-day and 60-day intervals. Simultaneously, the composite cubes are assessed for their suitability for confinement and vertical displacement. The findings reveal that stone aggregate with steel plate confinement demonstrates the highest compressive strength. Specifically, the compressive strength in stone aggregate with steel plate confinement is 3.04 and 3.52 times greater after 28 days and 60 days, respectively, compared to specimens without confinement.

INVESTIGATION OF STEEL ANGLE AND PLATE CONFINEMENT ON CONCRETE UNDER AXIAL LOAD USING DIFFERENT AGGREGATE

Steel and concrete are frequently used to construct composite structures, making steel-concrete composites the most common choice. This research aims to compare the confinement effects observed in stone aggregate, brick aggregate, and recycled brick concrete. This analysis evaluates the impact of various thicknesses of steel angles (3mm and 4mm) and steel plates (3mm and 4mm) on the confinement effect. Each aggregate is studied using 18 cube specimens: six with 3mm steel angle confinement, six with 4mm steel angle confinement, and six without steel angle and plate confinement. This study employed Portland Composite Cement and coarse sand at 1:2:4 and 0.45 water-cement ratios. The concrete is carefully built to meet specifications and retain the slump value. Compressive strength testing is conducted on the concrete specimens at the 28-day and 60-day intervals. Simultaneously, the composite cubes are assessed for their suitability for confinement and vertical displacement. The findings reveal that stone aggregate with steel plate confinement demonstrates the highest compressive strength. Specifically, the compressive strength in stone aggregate with steel plate confinement is 3.04 and 3.52 times greater after 28 days and 60 days, respectively, compared to specimens without confinement.

Effect of the Portland Composite Cement Addition on the Marshall Characteristics of the Cold Paving Hot Mix Asbuton

Effect of the Portland Composite Cement Addition on the Marshall Characteristics of the Cold Paving Hot Mix Asbuton

Abrams’ Law Formulation for Blended Cement Paste Incorporated with Ground Ferronickel Slag

Ground ferronickel slag (GFS) is a form of an industrial waste by-product generated during the smelting process of nickel ore that has been crushed and ground into fine powder. GFS is a pozzolanic substance that may be employed as an environmentally beneficial binding agent when blended with Portland cement. This research aims to apply the Abrams Law formulation to blended cement combined with GFS. GFS was utilized as a Portland cement composite (PCC) replacement at varying percentages of 0, 10, 20, 30, 40, and 50 wt.%. The blended cement paste incorporated with GFS was tested at three water to cementitious material ratio (w/cm) levels of 0.4, 0.5, and 0.6. After samples have been made, a compressive strength test is carried out. The research results showed that at 28 days, the optimum amount of GFS was found in the percentage of 20 wt.% induced the compressive strength by 40.41 MPa with a w/cm of 0.4. The equations based on Abrams’ Law have been proposed for estimating the correlation of 28-day compressive strength with w/cm in the range from 0.4 to 0.6. In addition, the hardened densities of binary blended cement paste were investigated. It was found that the density decreased with an increase of w/cm. The proposed equations provide the beneficial interpretation for estimating the compressive strength of blended cement paste based on the w/cm..