Use Of Industrial By-products Research Articles

Effect of Dry Mix Alkali Activated Slag Binder Composite Properties Cured in Ambient Condition

<p>A dry mix (solution-free) alkali-activated slag (a primary cementitious material) and/or fly ash based binder composition is developed that can be cast in-site and consequently cured at ambient temperature. Mortar specimens were cast by mixing slag and or fly ash, river sand, powder form alkaline activators (NaOH 14M, varying solids percentage of Na2SiO3) and water were thoroughly mixed in fabricated equipment. The dry density (28 days) of all specimens showed greater than 2200 kg/m3. The compressive strength (28 days) of all mixes was resulted in higher than 40 N/mm2. Among all the four mixes, a mix F103 with 90% slag, 10% fly ash, 30% Na2SiO3 and 14M NaOH at 3, 7 and 28 days curing showed overall higher compressive strength. It is due to fewer solids content of Na2SiO3. The experimental results indicated that solution free studied binder composite can be developed under ambient conditions eliminating other curing types without compromising in the strength. The studied sustainable mixes require only 12-15 percent water which is less compared to regular used mixes. Thus reduced water quantities can be achieved thereby protects the reduction in volume of water bodies, environment hazards, reduces CO2 emissions due to use of industrial by-products as main binders.</p>

Investigation on the sustainable use of different sizes of sawdust aggregates in eco-friendly foam concretes: Physico-mechanical, thermal insulation and durability characteristics

The extensive mining of natural resources, such as sand, for the construction industry, poses a hazard to the environment. To preserve the environment, the researcher must thus take into account the use of industrial byproducts rather than natural materials. The use of sawdust (SD) produced by the wood industry in foam concretes (FC) has been investigated in this study. This study examined the physical, mechanical, thermal, microstructural and durability characteristics of FC containing SD as a replacement of silica sand (SS) in the rates of 0, 25, 50 and 100 %. Two different SD sizes of 0–4 mm (SD4) and 0–1 mm (SD1) were used in the fabrication of FC mixtures. Protein-based foam agent was used to create FC mixtures. Fourteen mixtures with a 0.6 water/binder (w/b) ratio were produced at two different cement contents of 400 kg/m3 and 500 kg/m3. The fresh, mechanical, physical, and sorptivity characteristics of the FC mixtures were investigated in relation to the impacts of cement dosage, SD size, and SD replacement levels of SS. Durability of FC against high temperature, sulfate attack and freeze-thaw cycles was assessed. Costs and CO2 emissions from the blends were also assessed. The outcomes revealed that a 25 %SD1 integrated FC mixture with a cement content of 500 kg/m3 generated the highest 28-day compressive strength of 3.56 MPa with a 20 % strength loss as per the Ref.500 mixture. 17 % lower thermal conductivity was gained with the inclusion of 100 %SD4 as per the Ref.400 mixture. The mixture with 50 %SD4 and 400 kg/m3 cement dosage exhibited the best resistance to high temperature. The mixture with 25 %SD1 and 400 kg/m3 cement dosage showed the best frost resistance. SD incorporated mixtures showed better durability performance than the reference mixtures.

Assessment of flexural response of RC beams and unrestrained shrinkage of fiber-reinforced high-volume fly ash-based no-aggregate concrete and self-compacting concrete

The use of industrial byproducts as a substitute for cement in concrete production to improve its properties is becoming a widespread practice in producing sustainable concrete. Although research around the world emphasizes higher substitution levels of fly ash (FA) to accrue the benefits from the microstructure refinement, no attempt has been made to study the deflection behavior and drying shrinkage of concrete that is devoid of aggregates while supplementing 80% of cement with class F fly ash (F-FA). Two types of concrete are used to cast full-scale reinforced concrete (RC) beams of size 150×300×2200 mm. The first type is a novel no aggregate concrete (NAC) made up of 80% F-FA and 20% ordinary Portland cement (OPC). The second type is high-volume fly ash self-compacting concrete (HVFASCC), which has 60% F-FA as a cement supplement and is equivalent in compressive strength to NAC. The NAC is reinforced with polypropylene fibers (PF) in three varying volume fractions: 0.6%, 0.8%, and 1.0%. All the beams are tested under a simply supported four-point loading condition. The drying shrinkage strain and mass loss are measured for prisms of size 75×75×300 mm up to 220 days exposed at 20% relative humidity (RH) and 50 ºC temperature in a humidity oven for all the mixes. The mechanical properties are also assessed along with the water absorption (sorptivity). The results indicate that adding PF to the beams with NAC delays the formation of the first crack and improves the peak load, the ultimate load, and the ductility of the NAC beam. Additionally, the beams with PF exhibit lower mid-span deflection and ductile failure mode, improving the overall structural performance. Regarding drying shrinkage, the HVFASCC prisms record the lowest shrinkage strains of all mixes. Adding PF to NAC increases the initial and ultimate drying shrinkage strains. However, adding PF to NAC inhibits the rate of shrinkage strain over the test duration. This research enhances understanding of how PF affects no-aggregate concrete behavior, paving the way for more comprehensive construction materials.

Sustainable production of eco-friendly roofing tile using methyl ester residue as the alternative binder – A preliminary study

Making full use of industrial by-products is an effort to achieve ‘zero waste’ and promote greener development. Methyl ester residue (MER) is a waste commonly found in oleochemical manufacturers, such as palm oil mills. Contrary to conventional cement and clay, MER was employed as an alternative binder to fabricate a novel eco-friendly roofing tile, henceforth referred to as MER-RT. Parameters tested were transverse strength, water absorption, sulfate resistance, and fire resistance. During the optimization phase, a range of 6–11% of MER was mixed with a fixed composition of fly ash and fine sand, compacted and cured at 190° C for 12–48 hours. Considering the electrical energy consumption, the optimal curing duration chosen was 24 hours as this MER-RT achieved a dry transverse strength of 4112 N whereas curing for an additional 18 hours further contributed to only 16% strength gain. The optimal MER-RT was found to contain 10% MER as it showed the highest dry transverse strength (6410 N), the highest wet transverse strength (3681 N) and the lowest water absorption percentage (2.67%), meeting the American Society for Testing and Materials (ASTM) standards. Besides exhibiting minimal corrosion under the sodium sulfate test, the optimal MER-RT was non-flammable and did not undergo structural changes when exposed to fire. The study reveals the potential of both MER and fly ash as green binders and fillers for roof tiles, despite their origins as industrial waste.

Optimization of production variables for metakaolin and rice husk ash-based geopolymer cement

Geopolymer concrete has emerged as an eco-friendly alternative to conventional Portland cement-based concrete, boasting superior mechanical performance and a significantly reduced carbon footprint. This research delves into the effects of incorporating rice husk (RH) and metakaolin (MK) as supplementary materials in geopolymer concrete, with the goal of enhancing its properties and sustainability while making productive use of industrial by-products. The research commences with a comprehensive characterization of the raw materials, including rice husk ash (RHA) and metakaolin, via physical, chemical, and mineralogical analyses. Different combinations of RH and MK are then blended with an alkali activator solution to formulate geopolymer paste mixtures. The findings of this study reveal that the incorporation of RH and MK as partial substitutes for conventional materials in geopolymer concrete yields positive effects on its performance. The utilization of rice husk ash enhances workability and reduces the alkaline activation time of the geopolymer paste, leading to improved early-age strength development. This study demonstrates that the synergistic use of rice husk and metakaolin in geopolymer concrete promotes a more sustainable construction material with a diminished environmental impact. It offers valuable potential to guide engineers, researchers, and industry professionals in adopting sustainable and cost-effective strategies for enhancing the properties of geopolymer concrete, thus fostering its wider adoption in the construction sector.

Limestone and yellow gypsum can reduce cadmium accumulation in groundnut (Arachis hypogaea): A study from a three-decade old landfill site

Cadmium (Cd) toxicity has cropped up as an important menace in the soil-plant system. The use of industrial by-products to immobilise Cd in situ in polluted soils is an interesting remediation strategy. In the current investigation, two immobilizing amendments of Cd viz., Limestone (traditionally used) and Yellow gypsum (industrial by-product) have been used through a green-house pot culture experiment. Soil samples were collected from four locations based on four graded levels of DTPA extractable Cd as Site 1 (0.43 mg kg−1), Site 2 (0.92 mg kg−1), Site 3 (1.77 mg kg−1) and Site 4 (4.48 mg kg−1). The experiment was laid out in a thrice replicated Factorial Complete Randomized Design, with one factor as limestone (0, 250, 500 mg kg−1) and the other being yellow gypsum (0, 250, 500 mg kg−1) on the collected soils and groundnut was grown as a test crop. Results revealed that the DTPA-extractable Cd content in soil and Cd concentration in plants decreased significantly with the increasing doses of amendments irrespective of initial soil available Cd and types of amendment used. The effect of amendment was soil specific and in case of Site 1 (low initial Cd) the effect was more prominent. The reduction in DTPA-extractable Cd in combined application of limestone and yellow gypsum @500 mg kg−1 over the absolute control in soil under groundnut for the sites was by far the highest with the values of 83.72%, 77.17%, 48.59% and 40.63% respectively. With the combined application, Target Cancer Risk (TCR) of Cd was also reduced. Hence, combined application of limestone and yellow gypsum can be beneficial in the long run for mitigating Cd pollution.

Productive Management of Garbage: A Case of Rawalpindi Waste Management Company (RWMC)

This study quantifies the role and importance of Rawalpindi Waste Management Company, the whole processes that take place in it, and the policies on which they work. Urbanization has led to the increasing use of industrial by-products. Industries influence the environment in two folds one is creating waste during the manufacturing process and the second is products make more waste after they are used. Waste is managed by using (R-3) Reuse, Recycle, and Restore. Waste composition varied from time to time and region to region. RWMC’s target is Clean and Green Rawalpindi. Waste from Households, Hospitals, industries, and others is properly discarded by fulfilling the National Environmental Quality Standards. In this regard, the main concern is to focus on ‘’Sustainable Development’’ to secure our environment for the next generations.

Alkali activation of fly ash in self-consolidating concrete at low molar concentration

As a means of minimising the negative effects on the environment, the use of industrial byproducts in the building industry is becoming more popular. Recently, alkali activation of precursors has boomed in the market since activation of precursors improves mechanical properties and reduces the carbon footprint. However, one risk factor in alkali activation is molar concentration. This is because the increase in the molar concentration of sodium hydroxide/sodium silicate and the release of volatile substances from those acids is more harmful to the environment. Therefore, the present study investigates the activation of the precursor at low molar concentration, thereby equalising performance through the dosage of superplasticisers. In this regard, fly ash was activated at 5 M sodium hydroxide (NaOH) and replaced cement at varying percentages in the range of 0–30% by weight. The performance of self-consolidating concrete (SCC) was evaluated through fresh and hardened characteristics and microstructural analysis. The blended mixtures of SCC, activated fly ash (AFA) at 5 M sodium hydroxide, 0.89% of superplasticisers and 15% of replacement performed better than the control SCC. The outcome of the present study will provide a platform for activating a precursor at low molar concentration through the influence of superplasticisers.

Strategies to Assess the Impact of Sustainable Functional Food Ingredients on Gut Microbiota.

Nowadays, it is evident that food ingredients have different roles and distinct health benefits to the consumer. Over the past years, the interest in functional foods, especially those targeting gut health, has grown significantly. The use of industrial byproducts as a source of new functional and sustainable ingredients as a response to such demands has raised interest. However, the properties of these ingredients can be affected once incorporated into different food matrices. Therefore, when searching for the least costly and most suitable, beneficial, and sustainable formulations, it is necessary to understand how such ingredients perform when supplemented in different food matrices and how they impact the host's health. As proposed in this manuscript, the ingredients' properties can be first evaluated using in vitro gastrointestinal tract (GIT) simulation models prior to validation through human clinical trials. In vitro models are powerful tools that mimic the physicochemical and physiological conditions of the GIT, enabling prediction of the potentials of functional ingredients per se and when incorporated into a food matrix. Understanding how newly developed ingredients from undervalued agro-industrial sources behave as supplements supports the development of new and more sustainable functional foods while scientifically backing up health-benefits claims.

Commercial and recycled carbon-based fillers and fibers for self-sensing cement-based composites: Comparison of mechanical strength, durability, and piezoresistive behavior

The possible use of industrial by-products as carbon-based fillers and/or fibers to produce Multifunctional Cement-based Composites (MCC) with piezoresistive behavior for Structural Health Monitoring (SHM) was investigated. As fillers, Used Foundry Sand (UFS) and Gasification Char (GCH) were compared with commercial Graphene Nanoplatelets (GNP). As fibers, 6 mm-long recycled carbon fibers (RCF) were compared with virgin ones. Mortars were tested in terms of mechanical strength, water absorption, microstructure, and piezoresistive behavior. UFS and GCH are more effective than GNP in decreasing the mortar electrical resistivity (−30%), total porosity (−11%), water absorption (−27%) and in increasing the compressive strength (+10%). The combination of UFS with RCF in mortars provides the best results in terms of fluidity, strength, water absorption, and piezoresistive parameters. Generally, a lower mortar resistivity, even if with lower piezoresistivity properties, allows the use of cheaper instrumentation for SHM, thanks to the lower full scale and the better correlation strength between the change in resistivity with strain.

Microbial‑induced carbonate precipitation (MICP) technology: a review on the fundamentals and engineering applications.

The microbial‑induced carbonate precipitation (MICP), as an emerging biomineralization technology mediated by specific bacteria, has been a popular research focus for scientists and engineers through the previous two decades as an interdisciplinary approach. It provides cutting-edge solutions for various engineering problems emerging in the context of frequent and intense human activities. This paper is aimed at reviewing the fundaments and engineering applications of the MICP technology through existing studies, covering realistic need in geotechnical engineering, construction materials, hydraulic engineering, geological engineering, and environmental engineering. It adds a new perspective on the feasibility and difficulty for field practice. Analysis and discussion within different parts are generally carried out based on specific considerations in each field. MICP may bring comprehensive improvement of static and dynamic characteristics of geomaterials, thus enhancing their bearing capacity and resisting liquefication. It helps produce eco-friendly and durable building materials. MICP is a promising and cost-efficient technology in preserving water resources and subsurface fluid leakage. Piping, internal erosion and surface erosion could also be addressed by this technology. MICP has been proved suitable for stabilizing soils and shows promise in dealing with problematic soils like bentonite and expansive soils. It is also envisaged that this technology may be used to mitigate against impacts of geological hazards such as liquefaction associated with earthquakes. Moreover, global environment issues including fugitive dust, contaminated soil and climate change problems are assumed to be palliated or even removed via the positive effects of this technology. Bioaugmentation, biostimulation, and enzymatic approach are three feasible paths for MICP. Decision makers should choose a compatible, efficient and economical way among them and develop an on-site solution based on engineering conditions. To further decrease the cost and energy consumption of the MICP technology, it is reasonable to make full use of industrial by-products or wastes and non-sterilized media. The prospective direction of this technology is to make construction more intelligent without human intervention, such as autogenous healing. To reach this destination, MICP could be coupled with other techniques like encapsulation and ductile fibers. MICP is undoubtfully a mainstream engineering technology for the future, while ecological balance, environmental impact and industrial applicability should still be cautiously treated in its real practice.

Fly ash, GGBS, and silica fume based geopolymer concrete with recycled aggregates: Properties and environmental impacts

Recycled coarse aggregates (RA) are sustainable alternatives to natural aggregate (NA) in concrete; however, their mechanical performance has not been competent to the later. The partial replacement of Ordinary Portland Cement (OPC) with the use of industrial by-products for preparation of geopolymer concrete (GPC) has also harnessed great research interest. The objective of the current study is to investigate the technoenvironmental feasibility of using fly ash (FA), ground granulated blast furnace slag (GGBS), and silica fume (SF) in GPC to support the use of 100 % RAs in concrete. This study aims to optimize the proportion of GGBS, FA, and SF in the design mix for the best mechanical performance and eco-efficiency of GPC concrete as compared to conventional OPC concrete. Results indicated positive synergistic effect between FA, GGBS, and SF causing improved mechanical, and microstructural performance of RA based GPCs as compared to OPC concrete with RA. The highest compressive (52.15 MPa), flexural (5.81 MPa), and split tensile strength (5.23 MPa) were exhibited by GPC-MG15 with a cement substitution ratio of FA: GGBS: SF – 35:50:15 which were 18–34 % and 7–10 % higher than that of OPC concrete with NA and RA, compensating the effects of RA addition. The microstructural, and mineralogical properties analysed through SEM and XRD results depicted the densification of the matrix and formation of C-S-H, C-A-S-H, and N-A-S-H gels which could be the possible reasons for the improved performance of GPCs. The environmental performance of optimized GPCs analysed through Life cycle assessment (LCA) reported a 50–60 % reduction in the environmental impacts as compared to OPC concrete with NA. Although GPC-FG50 (GGBS: FA – 50:50) was also environmentally competent, GPC-MG15 was the most sustainable concrete mix which was environmentally superior while not compromising on the functional properties.

Influence of industrial by-product sulfur powder on properties of cement-based composites for sustainable infrastructures

The use of industrial by-products has attracted much attention globally in recent years because of the improved durability and sustainability of cement-based composites. To promote the application of sulfur powder (SP) in cement-based composites, a new hydrophilic modified sulfur powder (MSP) was prepared in this paper. The effects of unmodified sulfur powder (NSP) and MSP on workability, strength, permeability, dry shrinkage, and frost resistance of cement-based composites were thoroughly studied. Based on microstructural evolution, hydration heat, hydration product composition, and pore structure, the modification mechanism of NSP and MSP on cement-based composites were investigated. The results show that adding NSP improves the fluidity of cement-based composites while adding MSP has the opposite effect. An appropriate amount of MSP and NSP improves the durability of cement-based composites. However, both NSP and MSP reduce the 28d strength of cement-based composites. Compared with NSP, the incorporation of MSP reduces the hydration release rate, refines the pore structure, and improves the interface bond with the cement matrix. This study deepens our understanding of the influence of SP on the fundamental properties of cement-based composites, which also provides new perspectives on creating a sustainable built environment.

Mechanical and microstructural properties of lightweight CaO-activated fly ash composites in the presence of magnesium nitrate

The use of industrial by-products is required to replace cement to reduce carbon emission, and it is necessary to secure the strength of cementless binder to satisfy the required mechanical performance. The purpose of this study is to develop a new binder system composed of activated fly ash (FA) with CaO by adding magnesium nitrate ((Mg(NO3)2) as a new additive. To reveal the mechanism of strength enhancement, the influence of the dosage of Mg(NO3)2 on compressive strength, reaction products, and pore characteristics was observed. In addition, expanded perlite (EP) and expanded vermiculite (EV) were mixed in selected samples to develop a lightweight cementless composite. The results showed that adding Mg(NO3)2 significantly increased strength of CaO-activated FA system. In the reaction process, Mg(NO3)2 promoted the solubility of quicklime (CaO) to form more C-(A)-S-H and Ca–Mg–Al-(OH)-NO3-AFm phase and increased the initial concentration of silicon (Si) and aluminum (Al) from FA. The dense C-(A)-S-H formation enhanced mechanical strength by reducing porosity in binder matrix. When EP and EV were mixed in the selected binder, even if the strength decreased as the amount of EP and EV increased, the requirements for the strength and specific gravity of commercial autoclave aerated concrete (AAC) were satisfied.

Effect of Ordinary Portland Cement on Mechanical Properties and Microstructures of Metakaolin-Based Geopolymers.

Geopolymers have been considered a sustainable alternative to ordinary Portland cement (CEM I) for its lower embodied carbon and ability to make use of industrial by-products. Additionally, its excellent engineering properties of high strength, low permeability, good chemical resistance, and excellent fire resistance also strike a chord in the minds of researchers. The goal of this study is to clarify the effect of calcium sources on the mechanical properties and microstructures of the geopolymers. CEM I was chosen as the sole calcium source, while metakaolin was used as the source material. Five distinct geopolymers were prepared, having various ratio of CEM I: 0%, 5%, 10%, 20%, and 30%. The alkali-activator was a mixture of 12 M sodium hydroxide (NaOH) and sodium silicate (Na2SiO3), utilizing compressive strength and flexural strength to evaluate the changes of the geopolymers' mechanical properties. SEM, XRD, and FTIR were used to examine microscopic features, evaluate internal morphology, and analyze changes in components of the geopolymers containing different amounts of CEM I. The experimental results indicated that the optimal incorporation of CEM I was 5%. Under this dosage, the compressive strength and flexural strength of the geopolymers can reach 71.1 MPa and 6.75 MPa, respectively. With the incorporation of CEM I, the heat released by cement hydration can accelerate the geopolymerization reaction between silica-alumina materials and alkaline solutions. Additionally, the coexistence of N-A-S-H gel from components of an aluminosilicate mix and C-S-H gel from the CEM I promoted a more densified microstructure of the geopolymers and improved the geopolymer's strength. However, as the amount of CEM I in the mixture increased, the geopolymer matrix was unable to provide enough water for the CEM I to hydrate, which prevented excessive CEM I from forming hydration products, weakening the workability of the matrix and eventually hindering the development of geopolymer strength.

Self-Compacting Cementitious Composites with Heavy Fuel Fly Ash Replacement

Sustainability in construction is related to the use of industrial by-products, such as fly ash (FA). FA varies in chemical/mineralogical composition, depending on the raw materials burnt during its production. While FA produced from coal-fired power stations is extensively used in cementitious composites, heavy oil FA produced from the firing of heavy fuels (e.g., mazut or diesel) remains largely unused. This paper focuses on the novel use of heavy fuel fly ash (HFFA), as a replacement of Class F FA, in high-volume fly ash self-compacting composites. Two different grain size distributions of HFFA were used in quantities 5–15% w/w of cement and Class F FA for the production of the composites. The assessment of the physico-mechanical properties and microstructure of the end-products at different curing ages suggests that HFFA may be used at quantities ≤10% w/w, without any negative effects. In fact, depending on the quantity and grain size distribution of the HFFA, this may even improve some of the properties of the end-products in the long term, provided that a careful mix design is adopted. The findings show the potential of sustainable reuse of HFFA and are beneficial for its incorporation into design codes.

3D-Printable Materials Made with Industrial By-Products: Formulation, Fresh and Hardened Properties

Growing in the field of construction, 3D printing allows to build non-standard shapes and to optimise the use of resources. The development of printable materials requires good control of the fresh state of the material—between mixing and printing, a printable material has to evolve from fluid matter to be pumpable (extrudability) up to a matter supporting its own weight and those of superior layers (buildability). Our researches are focused on printable materials used in large printers, i.e., printers able to build structural pieces for buildings. As many pumps and printers can be used to achieve a wide range of parts, this paper presents a simple method to provide valuable guidance to users when a decision needs to be made about printable materials. In this context, our researches both try to maximise the use of industrial by-products to reduce the environmental cost of printed material and to propose tests easy to carry out in the field. Consequently, on the one hand, some printable materials that mainly include quarry washing fines have been developed and, on the other hand, Fall cone and Vicat tests have been used to determine the printability limit. By not focusing on a single formula, the novelty of this paper is to present to readers some parametric models, i.e., a methodology that can be used according to their own devices and applications. Based on a design of experiments, 20 formulas have been tested. Parameters that influence the quality of printing are highlighted. Mechanical tests results at hardened state and shrinkage measurements are also shown to demonstrate the ability of some formulas to be structural materials: compressive strengths at 28 days between 7.50 MPa and 18.40 MPa.

The Effect of Sodium and Magnesium Sulfate on Physico-Mechanical and Microstructural Properties of Kaolin and Ceramic Powder-Based Geopolymer Mortar

Recent trends in reducing the ecological footprint of the construction industry have increased the attention surrounding the use of alternative binding systems. Among the most promising are geopolymer binders, which were found to have the capability to substantially reduce the environmental impact of Portland cement use. However, even the use of this alternative binding system is known to be heavily dependent on the use of industrial byproducts, such as precursors and an alkaline source, produced through an energy intensive process. To address this and provide a greener route for this binding system, this study adopts the use of natural kaolin and raw ceramic powder as the main precursors. The activation process is performed by using solid potassium hydroxide in conjunction with sodium and magnesium sulfate, which are naturally available, to produce geopolymers. To assess the resulting geopolymer samples, 28 mixes are produced and a series of physico-mechanical and microstructural analyses is conducted. The results show that the use of ceramic powder can improve the physico-mechanical properties by reducing porosity. This, however, requires a relatively higher alkalinity for activation and strength development. These findings are further confirmed with the XRD and FTIR results. Nonetheless, the use of ceramic powder with sodium and magnesium sulfate is found to result in a more coherent and homogenous microstructure, compared to the geopolymers produced with potassium hydroxide and kaolin. The findings of this study point to the suitability of using sodium and magnesium sulfate for the cleaner production of kaolin and ceramic powder-based geopolymers.

Incorporation of Sugarcane Bagasse Ash to investigate the mechanical behavior of Stone Mastic Asphalt

Stone Mastic Asphalt (SMA) is one kind of new generation gap graded hot mix asphalt with higher content of asphalt with coarse aggregate proportions. The stone-on-stone interlock in SMA makes it superior rut resistant mix and favorable in adverse conditions. The usage of conventional fillers in SMA will lead to the creation of many environmental nuisances and entail additional cost during the production. The use of industrial by-products in the place of the conventional filler can be proven favorable to overcome enhanced production cost of SMA. In the present research work, one such largely produced industrial waste called, Sugarcane Bagasse Ash (SBA) is used as a filler in SMA by replacing conventional Ordinary Portland Cement (OPC) filler, and the engineering performances and cost effectiveness is examined. The SMA mixes were cast with 6.25% optimum binder content are varied with SBA of 2.5% (ACS1), 5.0% (ACS2), 7.5% (ACS3) and 10% (ACS4) by weight of the mix as filler and the results were compared with conventional SMA mix (ACS0). The results showed that, the inclusion of SBA demonstrated superior performances indicating the enhanced stiffness of mix (in terms of Marshall and flow characteristics). Moisture resistance of the SMA mix was improved up to 7.5% SBA replacement. Further, the drain-down test results revealed that, SBA can be effectively used as stabilizing agent. The mix ACS 1 and ACS2 shown a minimum rut depth in reference with ACS0. The mix with 5% SBA resists more number of repetitive loads than all the mix tested.

Evaluation of the use of blast furnace slag as an additive in mortars

Clinker is the raw material used in the manufacture of cement. However, this material is very harmful to the environment, since it is estimated that for every ton of clinker produced, about 1.0 ton of CO2 is released into the atmosphere. For this reason, alternatives were sought for the use of other materials that are less harmful to the environment. This has led to the use of industrial by-products with the aim of increasing their use and thus reducing the amount of carbon released into the atmosphere. Blast furnace slag is a by-product used in the manufacture of some cementitious products. The aim of this research is to conduct a study on the use of slag as an additive for cement or concrete. The mortar samples were tested according to Brazilian, American and European technical standards. Physical, chemical and compressive strength tests were carried out which confirmed the possibility of using the slag without chemical or thermal activation.