Potential Supplementary Cementitious Material Research Articles

The Optimum Percentage of Rice Husk Ash (RHA) as Partial Cement Replacement in Engineered Cementitious Composite (ECC)

Rice Husk Ash (RHA) is a potential supplementary cementitious material (SCM) in concrete production due to their capability of pozzolanic reaction. This research study on the fineness, workability and compressive strength of the RHA incorporated into Engineered Cementitious Composites (ECC) as a cement replacement alternative hence to determine the optimum percentage of RHA to be use in the ECC mix. The mix proportional of RHA-ECC was designed with RHA as the substitution of Portland cement at various percentages by volume, including 5%, 10%, 15% and 20% respectively. Physical characterization of RHA was determined by particle size distribution test. The workability of hand mixed mortar was determined by the flow table test. A total of 45 cubes of 50×50×50 mm was prepared and cured for 7, 14 and 28 days. These hardened mortars were test with the compressive strength test to study its mechanical property. Findings showed that the workability of RHA-ECC was decreased with increasing of the amount of RHA added. The compressive strength of RHA-ECC was best at 28 days with the 10% of replacement level compared to others. This study will provide both direction and knowledge on the application of RHA as a greener and sustainable cement replacement.

Transport properties of concrete containing lithium slag

Lithium Slag (LS), also known as Delithiated Beta Spodumene (DBS), is a by-product of lithium extraction from spodumene ore that contains active silicon dioxide and aluminium oxide making it a potential supplementary cementitious material (SCM) for concrete. This study investigated the transport properties of concrete at 28, 90, and 180 days by incorporating LS as an SCM with cement replacement levels of 20%, 40%, and 60%. The findings reveal that 20% to 40% LS enhanced compressive strength, and reduced permeable voids, water penetration, sorptivity, and porosity, leading to improved transport properties. As LS reacts slowly, 40% LS resulted in 18.34% higher compressive strength at 180 days compared to that of the control mix. Therefore, VPV, water penetration depth, and sorptivity co-efficient of concrete with 40% LS were found 15.96%, 24.79% and 38.46%, respectively, lower than the control mix. In addition, porosity analysis confirmed that with the increase of LS in concrete, porosity decreased over time. Moreover, SEM analysis demonstrated the development of CaCO3 crystals at 40% LS, further reducing porosity. However, beyond 60% cement replacement by LS, a decline in concrete properties was observed due to unreacted LS particles. Therefore, this research underscores the potential use of LS to enhance durability of concrete.

Effect of brick powders of various purities on hydration and compressive strength of Portland cement

AbstractThe availability of common supplementary cementitious materials (SCMs), as slags and fly ashes, is expected to reduce in the future. Among potential new SCMs, brick powders (BPs) have gained considerable attention. To study the effect of BPs as potential SCMs three BPs of different contamination were used for the experiments. The investigations included the R3 test as well as isothermal heat flow calorimetry and compressive strength measurements up to 91 days. In all tests, fly ash (FA) and limestone powder (LS) were used as a comparison. The reactivities determined in the R3 test could be explained by examining the chemical, mineralogical and physical properties of the BPs. Based on their reactivity in the R3 test, the BPs could be classified as pozzolanic, less reactive SCMs, with BPN showing the highest reactivity among the BPs. The results of the compressive strengths and the heat flow calorimetry confirm the reactivities determined in the R3 test. Based on the obtained results, BPN shows the highest potential for application as an SCM.

Influence of densified silica fume on engineering properties of concrete containing coal bottom ash aggregate.

Coal bottom ash (CBA) is a significant waste produced by the coal manufacturing power plant, harming the environment. CBA has been used in many studies to replace sand in cementitious materials. However, few studies have investigated the use of CBA in concrete as a sand replacement with densified silica fume (DSF) as a cement replacement. DSF is a potential supplementary cementitious material (SCM) to combat the engineering properties of concrete that are typically decreased when CBA is used as a replacement for natural aggregate. Therefore, the present study aimed to evaluate the influence of DSF on the engineering properties of concrete containing different content of CBA as a partial replacement for natural sand. The mix design of the ordinary Portland cement (OPC) and binary blended concrete comprised 90% OPC and 10% DSF by total binder’s weight. The CBA as the fine aggregate replacement was used at 25%, 50%, 75%, and 100% by total aggregate volume. The mechanical, porosity, absorption performance of DSF and CBA (DSF+CBA) concrete containing CBA as partial aggregate replacement material were investigated. DSF+CBA with 50% CBA replacement showed improved mechanical strength performance than control by 15% at 28d and 5.6% at 56d of curing. However, the total porosity performance for DSF+CBA concrete decrease as CBA content increases. In conclusion, the DSF as SCM in binary blended concrete with CBA content up to 50% achieved a better performance in terms of mechanical properties even though the porosity was marginally increased.

A Study on Effect of Mustard Husk Ash on Properties of Porous Concrete

Abstract: Mustard Husk Ash (MHA), a by-product of the mustard oil extraction process, has gained attention as a potential supplementary cementitious material in the construction industry. The incorporation of MHA in porous concrete offers the dual benefits of waste management and sustainable construction practices. The environmental advantages of utilizing MHA, such as reducing landfill waste and conserving natural resources. The review paper synthesizes the findings from various research studies that have investigated the influence of RHA on the properties of porous concrete. The impact of different percentages of Rice Husk Ash (RHA) as a partial replacement for cement is analysed. The fresh and hardened properties of porous concrete, including workability, compressive strength, water absorption, and porosity, are examined in light of the incorporation of RHA. The review paper identifies key trends and observations from the existing literature. It discusses the influence of water content and size of coarse aggregates on the performance of RHA-based porous concrete. It also addresses the challenges and limitations associated with the use of RHA, such as its effect on the water demand and workability of concrete mixes. By synthesizing the collective findings, the review paper provides valuable insights into the effectiveness and feasibility of RHA as a sustainable alternative in porous concrete production. It identifies knowledge gaps and areas for further research, emphasizing the need for long-term durability studies and performance assessments on MHA based on porous concrete under different environmental conditions. In conclusion, this review paper contributes to the understanding of the effect of mustard husk ash on the properties of porous concrete. It underscores the potential of MHA as a viable option for enhancing the sustainability and performance of porous concrete. The comprehensive analysis serves as a valuable resource for researchers, engineers, and practitioners seeking to explore the application of MHA in porous concrete and promote environmentally friendly construction practices.

Testing the volcanic material burying Pompeii as pozzolanic component for compatible conservation mortars

The aim of this work is to evaluate the potential use of ashes and lapilli that buried Pompeii as pozzolanic material for the formulation of conservation mortars. XRD analyses proved that the mineralogical composition of these volcanic products is consistent with the original pozzolanic mortars preserved at the archaeological site. A first set of pozzolanic mortars were prepared by using silica sand as aggregate. After curing the lapilli-based mortars, the measured compressive and flexural strengths proved to be higher than those of the control samples made of commercial pozzolan. A second set of samples, prepared by replacing silica sand with similar size coarse ash and lapilli, proved that volcanic aggregates further enhanced the mechanical properties by the formation of interfacial transition zones. The result of this research demonstrates that the volcanic material burying the archaeological site of Pompeii could be used as raw material in the formulation of compatible conservation mortars. As volcanic pozzolan is increasingly investigated as potential Supplementary Cementitious Material (SCM) for the production of sustainable concretes, preliminary considerations about the impact of the present work to this field of research are also provided.

The HYDRATION RATE OF PALM OIL FUEL ASH MODIFIED CEMENT PASTE AT DIFFERENT CURING TEMPERATURES

As concrete production around the world continuously increases, the high levels of carbon dioxide emissions from cement manufacture have resulted in the growing interest in the field of supplementary cementitious materials (SCM). Palm oil fuel ash (POFA) has been proven to be a potential SCM. This study presents the partial replacement of cement with POFA in four different samples (0%, 5%, 10%, and 15%). It is aimed at investigating the influence of POFA on the physical properties and the hydration rate of cement paste at different temperature conditions (15° C, 28° C and 40° C). The hydration rate of the POFA-modified samples was determined by measuring the amount of hydration water consumed under the different curing conditions. Physical properties investigated included apparent density, specific density, fineness, soundness, consistency, and setting time tests. The results for physical properties showed that fineness varied from 0.5% for the control sample through 1.01% for the 5% POFA modified sample to 1.20% for the 15% POFA modified sample. For soundness, 10% and 15% POFA-modified samples are 50% sounder than both the 5% POFA-modified sample and the 0% sample. Meanwhile, both consistency and setting time were proven to be proportional to the increase in the POFA content of the sample. As for the rate of hydration, globally, the consumption of hydration water was proportional to curing temperature. However, at 15oC curing temperature, results varied perplexedly: dropping from 0% to 5% before increasing at 10%, and then dropping from 10% to 15%. At room temperature, a gradual continuous raise was recorded and a drop was witnessed only for the 15% sample. At 40° C curing temperature, it was instead a continuous drop of the hydration rate.

Predicting Surface Resistivity on Concretes Containing Potential Supplementary Cementitious Materials Cured at Nonelevated and Elevated Temperatures

Abstract Time-series surface resistivity (SR) measurements with up to 56 days of hydration on concretes containing potential supplementary cementitious materials (SCMs) cured at an ambient temperature of 23°C and an elevated temperature of 38°C have the potential to indirectly determine the reactivity of many of these SCMs more accurately than conventional indirect testing metrics, such as the strength activity index in ASTM C618, Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete. SR time-series measurements can distinguish between microstructural densification caused by inert materials and densification caused by pozzolanic materials. However, it may be possible to assess pozzolanicity earlier in the test series, particularly when additional physical and chemical data regarding the material are known. The aim of this paper is to develop predictive models using machine learning on a broad range of both ASTM C618 conforming and nonconforming materials’ time-series SR curves based on the materials’ physical and chemical characteristics and early SR measurement data. Gaussian process regression models were used to predict the SR values of concretes cured at two different temperatures. These models can rapidly screen materials based solely on their chemical and physical characteristics to predict SR curves, which can then be used to determine a material’s suitability for beneficial use in concrete. Models using early age SR measurements were produced to predict the 56-day SR value for concretes cured at both elevated and nonelevated temperatures. This data-driven approach allows for the design of novel reactive materials, the inclusion of existing reactive materials in construction, and a reduction in testing durations.

Investigation of different paper mill ashes as potential supplementary cementitious materials

Integrating supplementary cementitious materials (SCMs) in cement-based construction materials is a key strategy for reducing environmental burdens and the greenhouse gas emissions related to cement production. Supplies of commonly applied SCMs such as fly ash and blast furnace slag are becoming limited, and therefore the search for alternative SCMs is of high significance. The present research investigates the viability of four paper mill ashes collected at different stages from the same incineration process as SCMs at different cement substitution rates (5–30 wt%). The ashes were first classified depending on their mineralogical and chemical composition, and their contribution to strength development of the prepared mortars is examined. Furthermore, the effects of the ashes on the hydration kinetics and the fresh and hardened properties of the prepared mortars were studied. The obtained results showed that a high level of SCM replacement accelerates the early hydration reactions and decreases the setting time. In addition, the incorporation of paper mill ashes increased the bound water depending on the ash type and resulted in strength development of the mortars at low replacement percentages (5–10 wt%). This study shows that the ashes belonging to type C medium acid based on bio ash classification could be incorporated as SCMs at a maximum level of 10 wt%, while those corresponding to type C low acid could be used up to 20–30 wt%. • Four paper mill ashes were characterized and classified based on the chemical and mineralogical composition then used as SCM. • Paper mill ashes corresponding to type C low acid based on bioash classification could be used as SCMs up to 20–30 wt%. • The addition rate of paper mill ashes controls the fresh properties and strength development of the mortars.

Evaluation of Solidified Wastewater Treatment Sludge as a Potential SCM in Pervious Concrete Pavements.

Waste and recycled materials have recently been used in the construction industry to comply with the principles of circular economy and sustainable development. The aim of this paper is to examine the potentials of solidified wastewater treatment sludge (SWWTS) as a supplementary cementitious material (SCM) in the production of lightweight pervious concrete pavers (LWPCP) suitable for pedestrian trails and rooftops (green) that comply with EU standards. Detailed characterization of SWWTS was performed, in order to understand its properties related to application as SCM, which led to the conclusion that it may be applied only as a filler, having 89.5% of Ca(OH)2. After thorough characterization, LWPCP samples were prepared and testing of physical and mechanical properties was conducted. The research showed that partial replacement of cement with SWWTS led to the decrease of all mechanical properties, ranging between 3.91 and 5.81 MPa for compressive strength and 0.97 to 1.23 MPa for flexural strength. However, all of the investigated mixtures showed a value higher than 3.5 MPa, which was defined as the lowest compressive strength in the range of pervious concrete properties. The addition of SWWTS led to a slight decrease in bulk density of the mixtures and an increase in water absorption. This could be explained by the reduction in hydration products that would fill in the micropores of the matrix, since SWWTS showed no pozzolanic reactivity. Pore sizes that prevail in the tested binder matrices are in accordance with the results measured on ordinary pervious concrete (the largest fraction of pores had a diameter between 0.02 and 0.2 μm). Low thermal conductivity nominates produced pavers as potential rooftop elements.

Assessment for utilization of tobacco stem ash as a potential supplementary cementitious material in cement-based composites

Present study investigates the effectiveness of utilizing tobacco stem ash (TSA) as the partial replacement of Portland cement (PC) on the properties of cement pastes and mortars. Cement pastes and mortars were fabricated by replacing cement with TSA at four replacement levels i.e., 3.75, 7.5, 11.25, and 15 wt% relative to cement. Setting time, consistency, and hydration activity tests were performed on TSA-based cement pastes. Moreover, water absorption, porosity, compressive strength, ultrasonic pulse velocity (UPV), and electrical resistivity (ER) testing were performed on TSA-based mortars. The pozzolanic behavior of TSA was assessed via Frattini test and strength activity index. Analytical characterizations such as x-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), thermogravimetric (TG), scanning electron microscopy (SEM), and energy-dispersive x-ray (EDX) analyses were also performed. The results indicate lower water absorption and apparent porosity, leading to enhanced compressive strength, UPV, and ER values for TSA-based mortars. The analytical characterizations show that TSA promotes the hydration reaction and formation of a greater amount of cement hydrates. The strength activity index and Frattini test results showed that TSA possesses moderate pozzolanic activity at a higher replacement level. While, for low replacement levels of TSA in cement composites, the hydration reaction is governed by rapid precipitation of portlandite due to higher hydration activity.

Upcycling of waste hydrated cement paste containing high-volume supplementary cementitious materials via CO2 pre-treatment

For past decades, supplementary cementitious materials (SCMs) have been widely used in the production of concrete for the purpose of reducing cement carbon footprint as well as enhancing the durability of concrete structures. Hence, most of the discarded concrete could contain a certain amount of SCM such as fly ash (FA) and ground granulated blast furnace slag (GGBS). This paper aims to improve the quality of waste hydrated cement paste powders containing 50% FA (FACP) and 50% GGBS (BSCP) with the aid of CO2 pre-treatment and study its feasible use as new potential SCM. The results show that carbonation changes the silicate network from Q2 units to Q3 units, and especially more obvious for the BSCP compared to FACP. The carbonation products of carbonated FACP are mainly calcite, whereas both calcite/aragonite co-existed in carbonated BSCP. Hence, the inclusion of 10%–15% of carbonated FACP and 10%–20% of carbonated BSCP in new cement paste can induce the formation of calcium aluminate mono-carbonate and improve the compressive strength. The 29Si NMR results also found that carbonated BSCP had a higher reactivity. Overall, both carbonated waste powders can be used as a new SCM up to 30% in the cement paste without compromising the 28-day strength.

Utilization of ceramic powder, calcined shale and sintered mullite as partial replacements of calcium aluminate cement

Supplementary cementitious materials (SCMs) are widely used with Portland cement. Similar approach was applied for calcium aluminium cement in this paper. Potential SCMs were ceramic powder, calcined shale and sintered mullite. Cement pastes with 5% or 15% of SCM were prepared and their phase compositions and basic physical and mechanical properties were studied. The analysed blended cements showed an advantageous performance not only at the ambient temperature, but also after high-temperature exposure up to 1400 °C. Ceramic powder had the most significant impact on the hydration process. Calcined shale caused a higher hydration degree, sintered mullite primarily affected the formed C-A-S-H phases.

Production of Environmentally Friendly Concrete Incorporating Bauxite Residue and Silica Fume

Toward a sustainable approach, concrete consumption is confronted with new challenges to developing and implementing cleaner technology. Concrete production is associated with excessive use of natural resources along with environmental pollution, which can be partially addressed through cement replacement with industrial waste. Red mud (RM), a toxic by-product of alumina refineries, is a potential supplementary cementitious material that has attracted researchers’ attention in the last years. In this study, 10 mixes were prepared and tested to investigate the simultaneous application of RM (10%, 15%, and 20%) and silica fume (SF) (5% and 7.5%) as cement replacement on concrete properties. The properties of fresh and hardened concrete and its durability were investigated. Overall, the mechanical performance of mixes decreased by increasing RM incorporation, whereas the simultaneous application of 20% RM and 5% SF as cement replacement yielded the same compressive strength as the reference. Furthermore, an evaluation of global warming potential and used water as environmental impacts in addition to a simplified cost analysis was performed on all mixes. Overall, the mix made with 10% RM and 7.5% SF achieved the highest consolidated performance score.

Characterization of harvest residues ashes and ceramic waste powders originating from Vojvodina as potential supplementary cementitious materials

Traditionally, residential buildings in Vojvodina have masonry walls. Various types of mortar of mineral origin are most often used for joining masonry elements and finishing. The total amount of mortar for the construction of one building is not negligible. The estimated annual consumption of mortar in Vojvodina is about 198 thousand tons i.e. 27 thousand tons of cement and about 31.5 thousand tons of hydrated lime. It can easily be seen conventional mortars based on cement and lime are unacceptable in the light of environmental protection and sustainable development in the contemporary construction industry. Therefore, there is a need for research and development of new, alternative types of binders, based on locally available renewable and/or waste materials. The ceramic masonry elements and tiles industry generates ceramic waste during the production process. This waste, in powder form, could potentially be used as supplementary cementitious material (SCM). Biomass ash, generated by the combustion of harvest residues, as a renewable energy source, is another alternative to cement in modern building composites. This paper emphasizes the physical, chemical, and pozzolanic characteristics of the available agro-waste ashes and ceramic waste powder, originating from Vojvodina. The results indicate relatively high pozzolanicity of all tested ceramic powders and biomass ash based on cob corn, owing to their high fineness and reactive silica content. Furthermore, a catalogue of collected waste materials, illustrating basic data on the raw materials, processing method, landfilling, available quantities, and their tested properties is given.

Valorization of kaolin mining waste from the Amazon region (Brazil) for the low-carbon cement production

The Amazon rainforest has 90% of Brazil's total kaolin reserves, and its mining is of great economic interest. However, the intense kaolin activity produces large quantities of deposited waste in tailing dams, generating a tremendous environmental and local economic liability. Such wastes have no economic value, but their high kaolinite composition can be interesting for the cement industry. Thus, this study aimed to valorize such material as a potential Supplementary Cementitious Material (SCM) in low-carbon cements. The calcined kaolin waste (KAW) was used with limestone and gypsum as clinker substitutes. Its performance was compared with calcined pure kaolin (KA) and an inert material (quartz powder, QP). The cements were evaluated regarding their setting times, water demand, rheological behavior, hydration and compressive strength at different ages. The most important results of the KAW are related to its better rheological behavior compared to KA and closer to QP when used in cement formulations. The kaolinite clay content played a significant role in the fresh properties assessed as well. The microstructural and mechanical performance of KAW cement is similar to KA, which highlights comparable reactivity. This study brings a new insight into the potential use of kaolinite-rich waste from the mining sector as SCM to be used in the local infrastructure of the Amazon region.

Development of a Commercial Screed Mortar with Low OPC Content by Incorporation of Biomass Fly Ash

Substitute Ordinary Portland Cement (OPC) by biomass fly ash (BFA) reduce the environmental impact produced by cement-based materials, and at the same time, decreased the economic and environmental burden associated with the landfilling of this waste. This study aims to evaluate the recycling of BFA as supplementary cementitious materials (SCMs) in a commercial screed mortar formulation. Two BFA varieties, both resulting from fluidized bed combustion of forest residues, were used to replace 17, 50, and 67 wt.% of OPC. The influence of simple pre-treatment processes of the BFA, such as sieving and grinding, in the fresh and hardened state properties of the mortars, was evaluated. The BFAs were characterized in terms of chemical (XRF) and mineralogical (XRD) composition, particle size distribution (laser diffraction-COULTER) and morphology (SEM). The prepared formulations were characterized in terms of workability, mass loss upon curing, bulk density, sorptivity (by immersion and capillary), flexural and compressive strength and durability to 25 freeze–thaw cycles. Both of the BFAs are potential SCMs. Substitution of 17 wt.% OPC with BFA complied with the product technical requirements for compressive and flexural strength (10 and 3 MPa, respectively), with the ground and sieved and just sieved BFAs perform slightly better than the as-received BFA.

Rice husk ash as a potential supplementary cementitious material in concrete solution towards sustainable construction

Rice husk ash as a potential supplementary cementitious material in concrete solution towards sustainable construction

Static Hardness Testing of Cement Mortars Containing Different Types of Recycled Construction Waste Powders

The present paper deals with the hardness of cement mortars prepared with recycled materials that are potential supplementary cementitious materials (SCM). Two potential SCMs (aerated concrete powder (ACP) and concrete powder) were investigated and compared with a reference (neat cement) sample and a sample containing metakaolin (MK). The long-term performance of the mortars was studied up to the age of one year. Based on the compressive strength tests at different ages, neither concrete powder nor ACP significantly decreases the compressive strength at a 10% substitution ratio. The samples were studied with two types of static hardness tests: the Brinell hardness test and the depth sensing indentation test at two different load levels. The hardness test results indicated that the standard deviation of the results is lower at a higher load level. In the case of metakaolin and concrete powder, the change in the compressive strength was observable in the hardness test results. However, in case of the ACP, the compressive strength decreased, while the hardness increased, which can be traced back to the filler effect of aerated concrete powder. Finally, using the DSI test, the hardness results were analyzed on an energy basis. The analysis highlighted that the change in the hardness is connected to the elastic indentation energy, while it is independent from the dissipated (plastic) indentation energy.

Rice-Straw Ash as a Potential Supplementary Cementitious Material: Influence of Thermochemical Conversion on Its Properties

AbstractAgro-waste ashes can be used as supplementary cementitious materials in concrete. Although many studies have been reported on the use of rice husk ash as a pozzolan, only limited studies ar...