Pozzolanic Properties Research Articles

Effect of carbonation technique on the performance properties of cRCP in composite cements

AbstractThe impact of carbonation technique on the performance properties of carbonated Recycled Concrete Paste (cRCP) in composite cements was investigated. The results show that despite differences in characteristics of carbonated material both techniques, wet and semi‐dry carbonation, lead to a carbonated material with valuable pozzolanic properties. The cement performance was further tested with different types of recycling material. Lab‐produced and industrially separated RCP were treated by means of enforced carbonation. All RCP materials were suitable for using concrete as a CO2 sink to sequester emissions from clinker production. The performance of the tested materials was similar regardless of the carbonation technique. Finally, it could be shown that industrial RCP material enables the production of ecofriendly composite cements for future applications.

Mechanical properties evolution of clays treated with rice husk ash subjected to freezing-thawing cycles

Rapidly growing urbanization and industrialization drive the continued development of soil stabilization and ground improvement techniques. Rice husk ash (RHA) is widely regarded as a highly promising construction material in civil engineering due to its excellent pozzolanic properties and has garnered significant attention from researchers. This paper presents an experimental study and a micro-mechanical discussion on the role of RHA in the mechanical improvement of soil. RHA was mixed with the native soil in varying proportions, ranging from 0% to 12%. Several laboratory tests were conducted, including standard proctor compaction tests, Atterberg limit tests, freeze-thaw tests, unconfined compression tests, X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM). The results indicated that the optimal moisture content (OMC) of the soil mixture increased while the maximum dry density (MDD) decreased with higher RHA dosage. The Atterberg limits of the soil mixture exhibited a positive correlation with the RHA content. A substantial enhancement in the soil's strength, stiffness, and ductility was observed upon the incorporation of RHA. It was noted that the strength loss of the untreated samples and those with 12% RHA was 34.91% and 12.89%, respectively, following 12 freeze-thaw cycles. Furthermore, XRD test results revealed that the treated specimen had an identical mineral composition to the control specimen, with no generation of hydration products. SEM analysis also highlighted that the filling effect of RHA significantly reduced pore content and pore connectivity within the soil, accompanied by a shift in the specimen's pores from mesopores to small and micropores. The excellent thermal insulation and heat retention properties of RHA, along with its pore-refining effect, make a positive contribution to enhancing the frost resistance of the specimens. These findings contribute to guiding the effective application of RHA in civil engineering, offering eco-friendly solutions for biomass waste management, and promoting the sustainable development of construction materials.

Effects of fineness and content of pozzolan on mechanical property, microstructure, and early-age chemical shrinkage of cement-based material

Natural pozzolan is a promising supplementary cementitious material for hydraulic concrete due to the pozzolanic effect, especially in the area where fly ash is scarce. In this paper, the physical properties of pozzolan were evaluated. The effects of pozzolan fineness and content on the microstructure, compressive strength, and early-age chemical shrinkage of pozzolan blended cement pastes were investigated. The results showed that the addition of pozzolan decreased the compressive strength of hardened cement pastes. The pozzolanic reactivity was closely related to the fineness of pozzolan, and higher pozzolan content led to lower strength. X-ray diffraction (XRD) and thermogravimetric (TG) analysis proved that Ca(OH)2 was consumed by reacting pozzolan, forming new calcium silicate hydrated (C-S-H). Besides, the addition of pozzolan caused the increase in porosity, which was reflected by the increase in macro-pores content. The chemical shrinkage of cement pastes was mainly determined by the hydration rate of cement, so the early-age chemical shrinkage was notably reduced after adding pozzolan due to its lower reactivity than cement clinker. In addition, finer pozzolan particles resulted in less macro-defects in the cement matrix, which enhanced the deformation resistance of hardened cement paste, and thus the chemical shrinkage was also decreased.

Formulation of inexpensive and green reactive powder concrete by using milled-waste-glass and micro calcium-carbonate – A multi-criteria optimization approach

In view of its high strength and durability, reactive powder concrete (RPC) is a promising construction material. The replacement of cement and silica fume with sustainable alternatives to RPC may provide significant benefits, however, there are challenges to overcome. In this study, calcium carbonate and ground waste glass powder were introduced as mineral mixtures to develop an environmentally friendly and cost-effective RPC mixture. The best flowability, proper compressive strength, and reduced cement content were achieved using a multi-objective simultaneous optimization approach based on the Derringer & Suich methodology. As a result of the study, 603 kg/m3 of cement was determined as the most suitable dosage for RPC. Additionally, the optimized mix contained 368 kg/m3 of waste glass and 118 kg/m3 of calcium carbonate, which had a beneficial impact on both cost and environmental considerations. As a result of numerous experimental tests, including compressive strength, elasticity modulus, chloride ion penetration, and drying shrinkage, the developed RPC's properties were validated and were comparable to the control mixture while showing superior drying shrinkage behavior. A further benefit of adding these admixtures was the reduction of superplasticizer dosage. Despite the optimized RPC's lower mechanical and chloride ion penetration performance at early ages, the performance discrepancy diminished over time due to the pozzolanic properties of waste glass powder. A significant characteristic of the optimized RPC was its superior drying shrinkage behavior throughout the testing period resulting from its reduced water dosage. Ultimately, the study highlights the potential of the addition of calcium carbonate and waste glass powder to RPC for sustainable concrete production at a low cost.

Analysis of the Influence of PET and Glass Packaging Waste Materials on the Physical and Mechanical Properties of Cementitious Composites

The limited availability of natural resources, such as sand, and the need to reduce CO2 emissions, which are produced in large quantities in the production of binding materials, indicate the need to look for alternative raw materials used in construction materials. At the same time, there is a strong need to utilise waste packaging materials, the global production of which is constantly increasing. This work aims to investigate the possibility of using recycled polyethylene terephthalate (PET), utilised as a partial substitute for fine aggregate, and waste glass, implemented as powder, serving as a partial substitute for cement in the manufacturing of the cementitious composites. An experimental study was carried out to evaluate the physical and mechanical properties of the resultant cementitious composites. The incorporated PET aggregate comprised 0%, 5%, and 10% by volume of silica sand and 0%, 10%, and 20% glass powder by weight of cement. The addition of waste raw materials augmented the flow of fresh mortars, predominantly subsequent to the introduction of PET recyclate. The deployment of artificial aggregate in mortars induces a decrease in the volumetric density. Concurrently, the mechanical properties of mortars enriched with waste materials exhibited a reduction, in terms of both compressive and flexural strength, with the detriment escalating in conjunction with the content of waste raw materials. An analysis of statistical significance of effects, grounded in an analysis of variance, is delineated within this document, pinpointing the quantities of waste raw materials that can be assimilated in mortars without inducing a substantial deterioration of strength properties. Through studies on phase composition, it has been demonstrated that the utilised glass waste, possessing a grain size analogous to cement, exhibited poor pozzolanic properties. The test results indicate that it is possible to partially replace cement with glass powder, up to 10%, and fine aggregate with PET waste, up to 5%, without a significant reduction in the mechanical properties of the material.

Incorporation of Bottom Ash as Aggregates in High-Volume Fly Ash (HVFA) Concrete

Research has been conducted on the utilization of coal combustion residues, specifically fly ash and bottom ash, in order to produce concrete products that meet national standards. Fly ash is employed as a high-volume replacement for cement in what is known as high-volume fly ash (HVFA) concrete. On the other hand, bottom ash is used as both fine and coarse aggregates, serving as a substitute for sand in the concrete mixture. Various characterizations were performed, encompassing the examination of the constituent minerals, crystallinity levels of bottom ash, water absorption, porosity, abrasion resistance, compressive strength, and morphological properties of the concrete specimens. Both fly ash and bottom ash exhibit significant proportions of SiO2, Al2O3, Fe2O3, and CaO, which possess pozzolanic properties and contribute to the compressive strength of the concrete. Concrete samples were produced with varying amounts of bottom ash and other ingredients according to the mix design. The highest compressive strength achieved after 28 days of curing was 27.57 MPa (designated as code B5), accompanied by the lowest porosity of 6.25%. Specimens with code B5 also displayed the lowest abrasion rate of 0.02 mm/minute and water absorption of 1.1%. These results suggest that the formulated mixture has the potential for developing concrete products suitable for walls and paving, adhering to the requirements specified in standard SNI 03-0349-1989 and SNI 03-0691-1996.

Characterization of net-zero pozzolanic potential of thermally-derived metakaolin samples for sustainable carbon neutrality construction

Metakaolin (MK) is one of the most sustainable cementitious construction materials, which is derived through a direct heating procedure known as calcination. Calcination process takes place substantially lower temperatures than that required for Portland cement, making it a more environmentally sustainable alternative to traditional cement. This procedure causes the removal of hydroxyl water from the naturally occurring kaolin clay (Al2Si2O5(OH)4 with MK (Al2O3·2SiO2) as its product. Kaolin naturally exists in large amount within 5°29′N–5°35′N and 7°21′E–7°3′E geographical coordinates surrounding Umuoke, Obowo, Nigeria. Alumina and silica are the predominant compounds in MK, which provide it with the pozzolanic ability, known as the 3-chemical pozzolanic potential (3CPP), with high potential as a cementitious material in concrete production and soil stabilization. Over the years, researchers have suggested the best temperature at which MK is derived to have the highest pozzolanic ability. Prominent among these temperature suggestions were 800 °C (3CPP of 94.45%) and 750 °C (3CPP of 94.76%) for 2 h and 5 h’ calcination periods, respectively. In this research paper, 11 different specimens of Kaolin clay obtained from Umuoke, Nigeria, were subjected to a calcination process at oven temperatures from 350 to 850 °C in an increment of 50 °C for 1 h each to derive 11 samples of MK. The MK samples and Kaolin were further subjected to X-ray fluorescence), scanning electron microscopy (SEM) and X-ray diffraction (XRD) Brunauer–Emmett–Teller (BET) tests to determine the microstructural behaviour and the pozzolanic properties via the 3CPP as to exploit the best MK with the highest cementing potential as a construction material. The results show that the MK heated at 550 °C and 800 °C produced the highest pozzolanic potentials of 96.26% and 96.28%, respectively. The enhancement in pozzolanic potential at optimum calcination temperature is attributed to an increase in the specific surface area upon calcination of kaolinite confirmed by BET results. The SEM and XRD results further supported the above result with the strengthened crystal structure of the MK at these preferred temperatures. Generally, 550 °C is more preferred due to the less heat energy needed for its formulation during 1 h of calcination, which outperforms the previous results, that suggested 750 °C and 800 °C in addition to longer hours of heat exposure.

High early pozzolanic reactivity of alumina-silica gel: A study of the hydration of composite cements with carbonated recycled concrete paste

Carbonated recycled concrete paste (cRCP) is a unique supplementary cementitious material with pozzolanic properties stemming from the alumina-silica gel. This study reveals that the high early strength of composite cements with cRCP is attributed to its rapid pozzolanic reactivity. 27Al and 29Si NMR investigations show that the alumina-silica gel is consumed after only 7 days of hydration. The rapid gel reaction results in the formation of a C-(A)-S-H phase with a low Ca/Si ratio. After 7 days, belite and remains of alite react further and increases the Ca/Si ratio of the C-(A)-S-H phase to a level typical for blended cements. As a result, a lower porosity forms already at early age, resulting in high strength. The reactivity of cRCP is influenced by its origin and carbonation conditions. Carbonation in sulfate-rich solutions enhances the gel surface area and accelerates the reaction. Slag remnants in cRCP react aiding to microstructure and strength development.

Experimental Study of Reinforced Concrete using red mud and Lime as Partial Replacement to Cement and Bamboo to Steel

Abstract: Red mud is an industrial waste material generated during production of alumina from bauxite by Bayer process Nowadays, the wastes are not having any industrial applications, so it can be innovatively using these wastes as a raw material in the civil engineering field. Availability of raw material required for manufacturing of cement and production of concrete are limited in nature. So as to overcome this problem it is very much essential to utilize the industrial waste materials and byproducts generated in manufacturing of cement and in concrete construction. Experiments Investigation have been conducted under laboratory condition to assess the strength characteristics of the aluminium red mud. The project work focuses on the suitability of red mud obtained for construction. 5 test groups were constituted with the replacement percentages 0%, 5%, 10%, 15%, 20% of red mud and 5% of hydrated lime with cement in each series. To achieve Pozzolanic property of red mud, hydrated lime was added. The job focuses on the practicality of red mud gotten for structure. 5 assessment groups were consisted of with the replacement percents 0%, 5%, 10%, 15%, 20% of red mud along with 5% of moisturized lime with concrete in each collection in M20 quality concrete. To acquire Pozzolanic house of red mud, moisturized lime was included. This paper points out another enticing direction for the proper usage of red mud.

Optimization formulation of low carbon MSWIFA cement-based composites modified by nano SiO2

The cementitious technique shows great potential as a solidification/stabilization treatment in the disposal of municipal solid waste incineration fly ash (MSWIFA). The utilization of MSWIFA as a supplementary cementitious material (SCM) offers the potential to substitute cement, thereby mitigating greenhouse gas emissions associated with conventional cement production. However, the lower active silicon content in MSWIFA diminishes its pozzolanic properties as an SCM. This paper explores a green and efficient pre-treatment approach for raw MSWIFA, and the treated MSWIFA was utilized as a SCM. The nano SiO2-modified MSWIFA cement-based composite (NMCC) was prepared by incorporating silicon-rich nano SiO2 (NS) to enhance the properties of the cementitious composite containing MSWIFA. The effects of MSWIFA content, water-to-binder ratio, and NS content on the NMCC were investigated in regards to its mechanical properties (compressive and flexural strength), fresh properties (fluidity and dynamic yield stress), and greenhouse gas emission (embodied carbon). The proportion and performance of NMCC were optimized by orthogonal experimental design. Range and variance analysis were applied to obtain the optimal formulation of NMCC. The findings suggest that NS can serve as an additional source of silicon to insufficient strength of cement-MSWIFA composites, which is attributed to the inadequate presence of silicon elements in MSWIFA. The comprehensive index analysis identified the NMCC with 15 wt% MSWIFA, 0.45 water-to-binder ratio, and 1.0 wt% NS as the optimal proportion. The optimal NMCC reduces embodied carbon by 38.91 kg CO2e/m3 compared to the cement control group, and can be effectively utilized in low-carbon buildings and engineering applications.

Analysis of The Addition Polypropylene Fibre and 8670 Mn Viscocrete added Material on The Split Tensile Strength and Modulus of Elasticity of Concrete

This study used waste coconut fibre and HDPE plastic as partial aggregate replacement materials. Coconut fibre ash has pozzolanic properties, which contain high silicate elements. High-density polyethene (HDPE) plastic has more potent, complex, opaque material properties and is more resistant to high temperatures. Superplasticizer is an admixture added to concrete during mixing and during placing to improve its strength performance. This study aims to study the effect of adding HDPE plastic as a substitute for coarse aggregate, coconut fibre ash as a substitute for fine aggregate and Viscrocrete-8670 MN on absorption, concrete compressive strength and elastic modulus of concrete. With variations in the addition of BN HDPE plastic, 0.5%, 1%, and 1.5%, the coarse aggregate passed 3/8 filter retained by filter no 4, 3% coconut fibre ash for each variation of concrete and Viscrocrete-8670 MN by 0.8% by weight of cement. The maximum value for each concrete test is the absorption value of concrete (4.23% for regular concrete), compressive strength (32.49 MPa for 1.5% HDPE concrete), and the modulus of elasticity (3152 MPa for 1.5% HDPE concrete).

Utilization of Steel Slag Waste as Construction Materials of Rigid Pavements

Roads play an important role in realizing the development and distribution of development results in certain areas. Pavement performance shows a decreased durability over time-related to how long the pavement construction can carry out its functions without experiencing fatal damage. This study aims to identify the effect of using steel slag as a substitute for filler with steel slag content of 0%, 1%, 2%, and 3% on concrete compressive and flexural strength values. This study used an experimental method by conducting experiments for testing the compressive and flexural strength of concrete specimens. The results showed that the use of steel slag as a substitute for filler obtained the average compressive strength value of MPa, 21.87 MPa, 22.17 MPa, and 28.47 MPa in concrete aged 28 days with steel slag content of 0%, 1%, 2% and 3% 25.07 respectively. The average flexural strength of concrete aged 28 days with steel slag content of 0%, 1%, 2% and 3% were 3.84 MPa, 2.83 MPa, 3.41 MPa, and 4.09 MPa respectively. The composition of 3% steel slag was the optimal composition as a filler replacement material. The pozzolanic properties of steel slag could increase the durability and density of the concrete specimen, but it required a long curing time and the increase in the initial strength of concrete slows down.

The Influence of Pulverized Fuel Ash (PFA) on the Thermal and Transport Properties of Foamed Concrete

The incorporation of materials derived from industrial waste presents a viable avenue for mitigating the exorbitant production expenses associated with building materials, while concurrently ameliorating the deleterious ecological ramifications of said waste. The utilization of pulverized fuel ash (PFA), an industrial residue resulting from the combustion of powdered coal in an electricity-generating facility, as a substitute for cement in the composition of concrete, is a viable option owing to its inherent pozzolanic properties. The present study endeavours to investigate the potential of Partially-Fumed Ash (PFA) as a viable substitute for cement in the production of foamed concrete (FC). The thermal and transport properties were meticulously assessed, with a particular focus on thermal conductivity, thermal diffusivity, specific heat capacity, water absorption, and porosity. A series of experiments have been undertaken wherein varying proportions of Portland Pozzolan Cement have been substituted for PFA, specifically at levels of 10%, 20%, 30%, 40%, and 50% by weight. The findings suggest a prospective application of PFA in the manufacturing of FC. The utilization of PFA (Pulverised Fuel Ash) assumes a pivotal role in enhancing the thermal conductivity, thermal diffusivity, specific heat capacity, water absorption, and porosity of FC. Therefore, it can be inferred that the utilization of PFA holds promising potential in the production of cost-effective, lightweight construction materials, while simultaneously mitigating the adverse environmental consequences.

Optimising concrete containing palm oil clinker and palm oil fuel ash using response surface method

Cement production led to the consumption of high energy and generated harmful gases, such as CO2. Therefore, the use of alternative materials becomes necessary. The research attempts to use palm oil clinker (POC) and ultrafine palm oil fuel ash (UPOFA) as a full replacement of coarse aggregate and partial cement replacement, respectively. This study aims to use the response surface method (RSM) to optimise the properties of concrete, namely, density and water absorption. The study investigated the density and water absorption of concrete using RSM. Results showed that the density reduced sharply owing to the full replacement coarse aggregate by POC aggregate. Meanwhile, water absorption increased significantly due to the rise in the POC aggregate replacement. However, water absorption decreased because of the use of UPOFA as cement replacement. The study recommended the use of more UPOFA as cement replacement because of its high pozzolanic property.

Employing spatial, hybrid and amplitude roughness parameters for unveiling the surface roughness features of mineral and organic admixtures

Scanning electron microscopy (SEM) permits to evaluate the surface morphology and surface roughness of pozzolans and admixtures. The field of mineral and organic admixtures has considerable interest in using SEM. However, several challenges are encountered which hamper the precision of quantitative roughness evaluation of mineral and organic admixtures using SEM and these challenges are usually bypassed in literature. In this research, surface roughness properties of pozzolans and admixtures were analysed from six perspectives: spatial parameters, hybrid parameters, amplitude parameters, surface roughness profiles, bearing ratio curves (BRCs) and amplitude density functions (ADFs). The generated roughness characteristics provided detailed information of roughness properties of the pozzolans and admixtures in a time efficient and cost effective way, which is usually very hard to achieve using experimental works. The comparisons of the obtained roughness data for the specimens showed considerable agreement with the roughness profiles and verified the interpretation of the established roughness profiles. Using the ADFs and BRCs for evaluating heights of the roughness profiles provided significant data encapsulated in the shapes of ADFs and BRCs. Moreover, the interpretation of the transformed logarithmic profiles seemed to have nearly retained similar meanings with the conventional profiles, although their scrutiny was observed to be complex. With brand new discussions on spatial, hybrid and amplitude parameters of mineral and organic admixtures, this research is a step forward in characterisation of roughness parameters of mineral and organic admixtures. This study expands the characterisation of pozzolans and admixtures, highlighting significant parameters to be considered in the application of mineral and organic admixtures.

The Impact of Milled Wood Waste Bottom Ash (WWBA) on the Properties of Conventional Concrete and Cement Hydration.

Wood waste bottom ash (WWBA) is a waste generated in power plants during the burning of forest residues to produce energy and heat. In 2019, approximately 19,800 tons of WWBA was generated only in Lithuania. WWBA is rarely recycled or reused and is mostly landfilled, which is both costly for the industry and unsustainable. This study presents a sustainable solution to replace a part of cement with WWBA at 3%, 6%, 9%, and 12% by weight. Problems are also associated with the use of this material, as WWBA could have a relatively large surface area and a high water demand. For the evaluation of the possibilities of WWBA use for cementitious materials, the calorimetry test for the cement paste as well as X-ray diffraction (XRD), thermography (TG, DTG), and porosity (MIP) for hardened cement paste with the results of physical and mechanical properties, and the freeze-thaw resistance of the concrete was measured and compared. It was found that WWBA with a large quantity of CO2 could be used as a microfiller with weak pozzolanic properties in the manufacture of cementitious materials. As a result, concrete containing 6% WWBA used to substitute cement has higher density, compressive strength at 28 days, and ultrasonic pulse velocity values. In terms of durability, it was verified that concrete modified with 3%, 6%, 9%, and 12% WWBA had a freeze-thaw resistance level of F150. The results show that the use of WWBA to replace cement is a valuable sustainable option for the production of conventional concrete and has a positive effect on durability.

Analysis of the properties of recycled aggregates concrete with lime and metakaolin

In recent years, the use of alternative materials in cementitious systems has attracted considerable interest due to their potential for augmenting the durability and performance of concrete. This research is investigating the use of three such materials as partial cement replacements in concrete: Recycled Concrete Aggregate (RCA), Limestone, and Metakaolin. RCA is a byproduct of the demolition of concrete structures that can be recycled as aggregate. Incorporating RCA into concrete reduces the environmental impact of waste disposal and reduces the carbon burden. Due to its pozzolanic properties, limestone, a sedimentary rock composed primarily of calcium carbonate, can be used as a substitute for cement. By substituting a portion of cement with limestone, the cement manufacturing process can substantially reduce carbon dioxide emissions. Metakaolin, a thermally treated form of kaolin clay, is yet another alternative material with pozzolanic properties. When used as a partial cement replacement, metakaolin increases the concrete’s strength, durability, and chemical resistance. It also contributes to lowering hydration heat and mitigating alkali-silica reactions, thereby enhancing the durability of concrete structures. In this investigation, cement is replaced by limestone powder which is varied from 0% to 50% and the addition of metakaolin of 20% in every mix design. RCA is also incorporated in the mix design as a replacement for coarse aggregate by 20%. In the experimental investigation, various tests were conducted on each mix slump test, density, compressive strength, sulphate attack, mass loss, x-ray diffraction (XRD), and scanning electron microscope (SEM). After the investigation, the compressive strength improved by 15.07%, when metakaolin was added, and when LS was used to replace 10% of the cement, the compressive strength increased by 13.49%. The features of the combinations were negatively impacted when more cement was substituted. Following an investigation of hydration products, filler and dilution effects were found, both of which have the potential to be connected to improved mix quality. A mix that contains 20% metakaolin and 10% limestone powder may be considered the ideal mix owing to its superior strength and sulphate resistance when compared to normal concrete. It consists of less effect on slump value and density, the compressive strength was increased, and minimum mass loss after the sulphate attack. M3 mix best performer among all mix designs. It shows that the mix design with 20% metakaolin and 10% limestone powder is best-suitable for future recommendations.

Utilizing halloysite nanotube to enhance the properties of cement mortar subjected to freeze-thaw cycles

This study investigates the impact of the long-term pozzolanic properties of halloysite nanotube (HNT) on the physical and mechanical properties, permeability, durability, and microstructural characteristics of cement mortar subjected to repeated freeze-thaw cycles. For this purpose, the two-year cured samples were exposed to 300 freeze-thaw cycles. Deterioration of the cement mortar surface was visually assessed and regularly quantified by mass loss and length change. Furthermore, helium porosity, electrical resistivity, and ultrasonic pulse velocity (UPV) were performed on cement mortar mixtures to elucidate the effect of repeated freeze-thaw cycles on permeability. In terms of mechanical properties, compressive and flexural strength tests were conducted; static elastic modulus and flexural toughness were also calculated. The frost durability of samples was analyzed using the relative dynamic modulus of elasticity and durability factor as the indexes to assess mortar's freeze-thaw resistance. Moreover, the microstructures of specimens before and after 300 freeze-thaw cycles were analyzed by scanning electron microscopy. Visual comparisons and experimental results demonstrated that the HNT introduction in cement mortars markedly enhances the frost resistance of plain mortar. It leads to the refinement of the cement paste pore structure and a reduction in its porosity due to the nucleating, filling, and long-term pozzolanic effects of HNT. It was found that the contribution of HNT's pozzolanic activity is the most important of these mechanisms. Therefore, less water penetration into the hardened cement composites occurs, which results in higher frost durability. The samples containing 2 wt.% HNT (by weight of cement) exhibited the lowest mass loss, expansion, porosity, and UPV loss due to repeated freeze-thaw cycles. The highest electrical resistivity and residual mechanical strengths also pertained to samples with 2 wt.% HNT. Hence, the HNT replacement dosage of 2 wt.% can be regarded as an optimal content for the cement mortars studied in this work. Finally, the two-way ANOVA revealed that HNT percentage is the factor with the greatest impact on mass loss, electrical resistivity, and compressive strength. In terms of length change, porosity, and flexural strength, the freeze-thaw cycle was the most statistically important factor.

Experimental Analysis on Partial Replacement of Cement by Glass Powder and Using of Steel Fiber

Abstract: Concrete consists of fine aggregate, coarse aggregate, water, and optional admixtures, such as Portland cement or another hydraulic cement. Because of its massive resource consumption, the concrete industry poses a serious danger to the sector's long-term viability. The concrete industry is struggling in part because of concerns about the environment and the economy. Many studies are currently being conducted on the utilisation of waste materials like Pulverised Fly Ash (PFA) and Ground Granulated Blast Furnace Slag (GGBS) as supplemental cementitious materials. Similar to PFA and GGBS, waste glass powder can be used to partially substitute cement during the hydration reaction. To some extent, waste glass can substitute cement in concrete and contribute to strength development if it is ground to a very fine powder and demonstrates pozzolanic properties due to its high SiO2 content. This research examined the Compressive, Tensile, and Flexural strengths of concrete that had been aged for up to 60 days with concrete that had been partially replaced with Glass Powder at percentages ranging from 0% to 40%. The aggregate test findings suggest that Waste Glass Powder could be used as a suitable cement replacement in construction projects. Fibre reinforced concrete (FRC) is a composite building material made from small, discontinuous fibres that are randomly distributed throughout the concrete part. Steel, glass, and polymer fibres, as well as fibres originating from natural sources, are the most common types of fibre used in cement-based composites. The tendency of fibres to be more closely spaced than traditional reinforcing steel bars makes them more effective at preventing cracking. It's important to note that fibre is not a suitable replacement for steel bars when reinforcing concrete.

Effect of processed sugarcane bagasse ash on compressive strength of blended mortar and assessments using statistical modelling

There is much agriculture and non-agricultural waste that contains pozzolanic material, which can be recommended to use as a partial replacement for Ordinary Portland Cement (OPC). One of the waste products from sugar industries, which possess pozzolanic properties, is Sugar Cane Bagasse Ash (SCBA). Because of the negative impact associated with cement production, OPC is being replaced by several supplementary cementitious materials / pozzolanic materials. In the current study, an effort has been made to use the SCBA by partially replacing the OPC for mortar studies. SCBA has been processed to enhance the chemical and physical properties. OPC is partially replaced by Processed Sugar Cane Bagasse Ash (PSCBA) up to 30% by a 5% increment. PSCBA blended cement mortar contains different proportions of PSCBA blended cement: river sand as 1:3, 1:4, and 1:5 with different water-to-binder (W/B) ratios based on the flow studies. Experimental research was done to determine the effects of the W/B ratio, river sand, and PSCBA on the formation of the cube compressive strength of PSCBA blended cement mortar for curing times of 7, 14, 28, 56, and 112 days. An increase in compressive strength about 6.4%, 9.3%, and 8.2% for 1:3, 1:4 and 1:5 with different W/B ratios for 28 days is reported. Based on the investigational results, the coefficients of strength for various relationships proposed by different researchers have been calculated for the binder: sand ratio as 1:3 and 28 days curing period. Various relationships, including Abraham, Feret, Singh, and Bolomey law are used to validate the mixes of the PSCBA blended cement for different water-to-binder ratios and different curing periods. A novel relation has been developed through the extension of studies to forecast the compressive strength of PSCBA blended mortar mixes with various W/B ratios for various curing times.