Sugar cane bagasse ash (SCBA) is an abundant byproduct of the sugar and ethanol industry. SCBA is generally used as a fertilizer or is disposed of in landfills, which has led to intensified ...environmental concerns. In recent years, SCBA research has mainly been focused on utilization in construction materials due to the abundance and pozzolanic characteristics of SCBA. In this paper, a comprehensive review of the state-of-the-art morphology, physical properties, chemical composition, and mineralogical composition of SCBA is presented. Studies indicate that SCBA is a potentially promising construction material. The applications of SCBA as a pozzolanic material, a new source for preparing alkali-activated binders, aggregates, and fillers in construction materials, are summarized. The impacts of SCBA on fresh and hardened concrete properties are highlighted, including the physical properties, mechanical strength, microstructure, and durability. Key factors that govern pozzolanic activity are discussed in detail, including calcination and recalcination temperatures, and durations, fineness, loss on ignition (LOI), and crystal silicon dioxide. Finally, further research on the optimal and broad utilization of SCBA in construction materials is recommended.
•Calcination and milling pre-treatments on pozzolanic activity of zeolites was evaluated.•Compressive strengths and the reaction rate of the natural zeolite were evaluated.•Pozzolanic activity of ...natural zeolites increase for each pre-treatment.•Most effective individual pretreatment was grinding.•Pretreatments as a combination are the best option, but in a specific order.
In this research, the effects of calcination and conventional milling, individually and as a combination of pre-treatments, on the pozzolanic activity of natural zeolites were analyzed and evaluated. The characterization of the material was done by techniques such as fluorescence and X-ray diffraction, thermogravimetric analysis, particle sizes distribution, Brunauer-Emmett-Teller (BET) - specific surface area, and porosity. Calcination was performed at 300, 600, and 800 °C for 5 h. Conventional milling was carried out to raw zeolites and after calcination in a ceramic ball mill for 3 h. Pastes and mortars with replacement percentages of 30, 40, and 50% were prepared for evaluating the pozzolanic activity, compressive strengths, and the reaction rate of the natural zeolite type mordenite and heulandite-clinoptilolite present in the material. It was found that the pozzolanic activity of natural zeolites increases for each pre-treatment separately and together after 8 days of hydration. The most effective individual pretreatment was grinding, but pretreatments as a combination bring many benefits such as the higher increase in compressive strength and non-agglomeration of the material in the mill.
Sugarcane bagasse ash (SCBA) has been pitched as a feasible supplement that can ease the sustainability issues associated with cementitious materials. In this respect, SCBA has been well researched ...with over 100 journal publications. However, there is a scarcity of comprehensive reviews detailing the research developments so far. Therefore, this study is a holistic review with a large scope, content and coverage that emanated from a comprehensive dissection of the literature. The study systematically reviewed the SCBA's origin of pozzolanicity, processing approaches, sustainability potentials, and performance in cementitious materials. The performance entailed characterisation, pozzolanic activity, microstructure refinement, fresh and rheological properties, mechanical and durability properties. SCBA processing is key to its reactivity and performance; hence, recommendations were made on the best processing approach. Performance ranging from 80 to 160% of the control (without SCBA) exist in the literature. Such performance emanates from a conservative use of about 20–25% or further processing that yields optimum contents up to 50%. This study serves as an up-to-date appraisal of data and researches related to the use of SCBA in cementitious materials.
•Comprehensive review on SCBA use in cementitious materials.•Origins of SCBA pozzolanic activity.•Approaches and recommendation on improving SCBA pozzolanic reactivity.•Potentials of SCBA in improving sustainability of the cement industry.•Conservative 20–25% content of SCBA in cementitious materials with extensions up to 50%.
A large quantity of Rice husk ash (RHA) is disposed of as waste material and leads to severe pollution. The pozzolanic behaviour of RHA enables its application in the construction sector, which is an ...alternative solution to its disposal. This paper critically reviews the use of RHA in the cleaner production of construction products such as blended cement, alkali activated binder, and bricks. The use of RHA in other construction applications such as soil stabilisation and subgrade treatment are also reviewed. Moreover, scientific insights on the physical, chemical, and mineralogical properties of RHA, which plays an important role in the engineering properties of RHA blended construction products, are presented. On assessing the effect of RHA on different construction sectors, the addition of 10–20% of RHA is reported to enhance the short term and long term engineering properties of construction products. Hence, RHA is energy and cost-effective solution for the construction industry. In addition, based on the extensive review, the paper also provides pathways and recommendations for utilisation of RHA in the cleaner production of construction.
Display omitted
•Utilisation of rice husk ash in construction products is comprehensively reviewed .•Enhancement in properties of rice husk ash based construction products is presented.•A framework is given for the varied uses of rice husk ash in construction sector.•Directions for future research studies on the use of rice husk ash are recommended.
Display omitted
•The study is a review of recent progress in Rice husk ash (RHA) retaining geopolymer.•RHA is a biogenic Si source for synthesizing low-cost activators in geopolymers.•The inclusion ...of RHA ∼15 wt% ascribes the positive effects on the geopolymer.•RHA added filling effects, and strong Si-O-Si bonds aid in enhancing strength.•RHA has high potential as an alternate of the natural resources for geopolymer.
The paddy farming countries generate enormous amounts of by-products, i.e., Rice husk (RH), through the milling process. It is typically utilized in the boiler as a fuel that produces a solid waste, i.e., Rice husk ash (RHA). It retains a high amount of biogenic silica and has shown good pozzolanic reactivity that can be used as a sustainable construction material. Consequently, over the last decade, a large number of investigations have been performed to utilize RHA for the production of cementitious materials, e.g., geopolymer. The geopolymer technology offers numerous advantages Over ordinary portland cement (OPC), such as reducing CO2 emission, excellent physico-mechanical properties, and feasibility to utilize waste ingredients. The present study reviews the utilization of waste RHA about the cleaner production of geopolymer. The effects of RHA inclusion on key properties like workability, setting time, compressive strength, and durability are intensely discussed in this study. On evaluating the effect of RHA on geopolymer, the incorporation of 10–20 wt% RHA is ascribed to improve the short and long-term properties of geopolymer. Thus, the use of RHA is a sustainable and environment-friendly pathway for the construction industry. Furthermore, based on the present review, the article also provides future research directions for developing more sustainability and recommends utilizing the RHA for cleaner production of geopolymer.
To better facilitate the resource utilization of secondary aluminum ash and reduce the consumption of Portland cement, this study investigates the pozzolanic activity grinding fine powder of ...secondary aluminum ash sintered and ground fine powder (MP) in a Portland cement matrix with different fineness and content. The mechanism of volcanic ash activity was explored using microscopic testing techniques such as XRD, FTIR, TG, SEM, and MIP. The outcomes revealed that as the MP content increased, the fluidity of the cement-based matrix exhibited a declining trend. The addition of MP has a diluting effect on Portland cement, resulting in a decreasing trend of strength activity index with the increase of MP content. Furthermore, under identical content conditions, much finer MP showed a reduction in its pozzolanic activity within the Portland cement-based matrix. Hydration processes and microscopic tests indicated that the addition of the coarser MP particle resulted in higher pozzolanic activity, which is attributed to the faster hydration rate, lower porosity, and higher microstructural compactness. Simultaneously, with an increase in MP content, the porosity and detrimental pore content of the cement-based matrix notably increased, and the content of hydration products reduced.
Display omitted
•The pozzolanic activity of MP in Portland cement matrix was characterized.•The influence of MP on the hydration kinetics of Portland cement was studied.•The pozzolanic activity mechanism of MP in Portland cement matrix was analyzed.
Natural resources, along with critical raw materials, are increasingly considered a focus for technological applications. Widely available and inexpensive natural resources, such as zeolite-rich ...geomaterials, possess minero-chemical characteristics that make them very useful in various technological applications, representing a strategic choice with a strong green connotation. In this research, the possibility of recycling waste powders from quarrying operations of zeolite-rich tuffs in technological applications for the construction sector and drug delivery was investigated.
Waste powders collected from quarries operating on the Sorano Formation (Tuscany - Italy), were used for a preliminary characterization, performed to evaluate zeolite content and potential pollution deriving from industrial processing.
Thereafter, the specific technological characterization was carried out to define the waste attitude to represent a promising candidate raw material for Lightweight Expanded Aggregates (LEA) production, partial substitution component with pozzolanic activity in cement formulations, carrier for active pharmaceutical molecules.
Experimental results, obtained following European normative, proved that was possible to produce waste-based LEA with comparable features with those reported for currently marketed products, that waste powders exhibited pozzolanic activity evidencing the possible use as addition for blended cements and, finally, the use of a cationic surfactant determined a surface-modification of natural zeolites (contained in waste samples) which encouraged for an early loading trial of active pharmaceutical molecules.
This research can be safely extended to other quarry waste, with similar mineralogical and chemical composition, leading to a strong contribution in the waste management of this sector.
•The Sorano Formation is quarried and processed with a huge production of waste mainly composed of zeolites.•Zeolite-rich waste is suitable for production of lightweight aggregates meeting technical requirements for building sector.•Zeolite-rich waste can be considered as a partial substitutefor cement additions due to the pozzolanic activity index.•Functionalisation of the zeolites from the Sorano formation waste enables the loading of pharmaceutically active molecules.
The manufacture of cement is considered as a high energy consumption and environmental pollution process, and it is necessary to figure out a way to reduce the consumption of cement in construction ...industry. The waste clay brick is a kind of construction waste with pozzolanic activity, which could be used to prepare blended cement after grinding. However, the particle size of clay brick powder (CBP) will influence its pozzolanic activity and properties of blended cement, which needs to be clarified. Therefore, in this study, the pozzolanic activity of CBP and properties of blended cement containing CBP were investigated. The results show that with the increase of grinding time, the CBP particles tend to be refined and spherical, which will increase the specific surface area and pozzolanic activity of CBP. The decrease of CBP particle size in blended cement paste can accelerate the early-age hydration and decrease the setting time since the ultrafine CBP could become the crystallization nucleus. The compressive strength of mortars with 30% CBP is 10%–35% lower than that without CBP, and the smaller the CBP particle size, the faster the compressive strength grows. Moreover, the hydration products and pore structure results also prove that the CBP with smaller particle size will consume more calcium hydroxide to react, which could make the microstructure denser and obtain stronger compressive strength growth at later ages. Meanwhile, the environmental impact and cost calculations indicate that the energy intensity and CO2 emissions of blended cement are obviously lower than Portland cement. It could be concluded that the pozzolanic activity of CBP will be enhanced with the decrease of particle size, and this research provided the reference for application of waste clay brick to produce green construction materials.
•Pozzolanic activity of waste clay brick was enhanced by mechanical grinding.•CBP with smaller particle size could accelerate the early-age hydration.•Paste containing CBP with smaller size showed better performance at later ages.•Environmental impact and cost of CBP manufacture were quantitatively calculated.
•The mortar strength can be improved by replacing 10% cement with the recycled powder.•The energy consumption of grinding ACB into finer powder is higher than SCB powder.•The ACB powder particles ...contain 2–3 μm pores.
This paper intends to study the recycled powder generated from aerated concrete blocks and sintered clay bricks. The powder was divided into different groups according to particle sizes with ranges of 0–0.045 mm, 0.045–0.075 mm and 0.075–0.15 mm. First, the energy consumption to prepare the powder with different particle sizes was calculated according to the grinding time. Various groups of powder were used to cast mortar samples with cement replacements of 10%, 20% and 30%. The slump and slump loss of the fresh mortar and the mechanical properties of the hardened mortar after 28 days of curing were investigated, as well as the shrinkage within 60 days. The results show that aerated concrete blocks are easier to crush than sintered clay bricks, but the energy consumption of grinding aerated concrete blocks into powder finer than 0.30 mm is higher than that of grinding sintered clay brick powder, which is verified by the energy consumption analysis. The mortar strength can be improved by replacing 10% cement with the recycled powder. The activities of three kinds of powder, from fine to coarse, obtained from aerated concrete blocks are 98.4%, 83.6% and 74.6%. For sintered clay brick powder, the activities are 73.7%, 87.9% and 85.8%. The aerated concrete block powder particles contain 2–3 μm pores, which is the reason that it severely reduces the fluidity of the mortar, leading to considerably more shrinkage.
Phosphorous slag (PS), is currently utilized in concrete industries with a low cement replacement rate of 20–30%, due to its low pozzolanic activity. This study was thus performed to enhance the ...pozzolanic activity of PS by chemical modification with MgO additions of 0 %, 5 %, and 10 %. The addition of MgO facilitates the conversion of structural units from Q4 to Q3 and Q2, favoring the depolymerization of silicate glass. Composite cements were prepared by replacing 40 wt% of Portland Cement (PC) with modified PS (MPS). Significant retardations in setting time were observed for the S-CMPS mortars, due mainly to the low early reactivity and presences of phosphate and fluoride, which can be mitigated by increasing the MgO content in MPS. The MPS richer in MgO released more active Si and Al to take part in pozzolanic reaction, contributing to intensified CH consumptions and C-S-H and C-A-H formations. The paste of S-CMPS10, acquired higher compressive strengths than those for S-PC and other S-CMPS pastes at both 28 and 90 days of curing, with SEM images showing a compact microstructure of more gel phases and less pores. These results indicate that the modification with MgO addition is an effective way to enhance the pozzolanic activity of PS, which can be potentially utilized as an economic and environmental cementitious material. However, there are also some limits in this study, for instance, effects of temperature and leaching behavior on the mechanical properties of S-CMPS pastes, which are planned in the future research to enhance the sustainable utilization of PS.
Display omitted
•An effective strategy to enhance the pozzolanic activity of granulated phosphorous slag (PS) by the addition of MgO to facilitate network depolymerization of PS glass.•A quantitative investigation on the relationship between pozzolanic activity and SiO4 structural properties of the modified PS (MPS).•A possibility for mitigation of the setting time retardations by increasing MgO contents in MPS to achieve a higher cement replacement rate of 40 wt%.•A comparative analysis of compressive strengths for the S-PC and S-CMPS pastes at different curing ages, explained by the results of hydration product and microstructure.
PDF
