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The transformation of byproducts and wastes generated by agro-food companies is of high importance since only a small portion of plant material is utilized directly for human consumption. Squash pumpkin is greatly used in Portugal and as by-products of its processing are generated tons of shell and seeds. In this study we aim to evaluate the potential of these wastes as sources of beneficial and bioactive compounds (antioxidants and antimicrobials), studying the effect of different extraction solvents and drying methods. The samples (fresh and cooked) were freeze-dried and oven-dried followed by extraction with different solvents that revealed the following decreasing order of efficiency: 70 % ethanol, 70 % methanol, 70 % acetone, ultra-pure water and 100 % dichloromethane. The oven-dried samples showed higher values of antioxidant activity and phenolic content, with exception of the values of phenolics for the seeds material. The shell samples presented higher values (1.47 - 70.96 % inhibition) of antioxidant activity and total phenolic content (2.00 - 10.69 mg GAE/g DW). A positive correlation was found between these two parameters on the shell samples, however the squash seeds revealed a negative correlation between the phenolic content and the antioxidant activity. The results show that these industrial agro-food residues are potentially good sources of bioactive compounds with health benefits. [ABSTRACT FROM AUTHOR]

Increased care about the environment is currently evidenced by governmental, industrial, and consumer concern for ozone depletion, solid and liquid waste disposal, and pollutants. This concern has led to an increase in marketing of the “environmentally friendly” aspects of products. In the past, fly ash was generally released into the atmosphere, but pollution control equipment mandated in recent decades now requires that it is captured prior to release. In order to upgrade expansive soils as construction materials, fly ash, which is a waste material, has been selected and successfully used for stabilizing expansive clays in the Thrace region. The strength characteristics of the stabilized soils were measured. Depending upon the soil type, the effective fly ash content for improving the engineering properties of the soil varied between 8% and 12%. Using fly ash in roadwork projects will help the environment reducing the deposited amounts. [ABSTRACT FROM AUTHOR]

Purpose: Using reactive industrial by-products (IBPs) to reduce phosphorus (P) losses associated with diffuse water pollution is a potentially cost-effective mitigation strategy. However, IBPs must be screened to assess their effectiveness and optimum application rates. This requires accurate estimates of parameters such as the maximum P sorption capacity. Traditionally, these parameters have been derived from the Langmuir model applied to data from batch sorption experiments following a 24-h equilibration period. In this paper, we examined (i) how equilibration time can influence estimates of the maximum P sorption capacity for IBPs and (ii) the relative P sorption characteristics of a range of IBPs available in the UK. Materials and methods: Four IBPs containing different reactive components including ochre, aluminium (Al)-based water treatment residual (WTR), iron (Fe)-based WTR and Fe-lime (CaO)-based WTR were selected for this study. The maximum P sorption capacities of these IBPs were determined using a linearized Langmuir model applied to batch sorption data collected at different equilibration times of 24 h, 5 days and 10 days. Results and discussion: The maximum P sorption capacity of ochre, Al-based WTR, Fe-based WTR and Fe-CaO-based WTR estimated from the linearized Langmuir model following a 24-h equilibration period was 10.1, 13.7, 2.4 and 9.3 mg P g, respectively. However, extending the equilibration time from 24 h to 5 days increased the estimated maximum P sorption capacity for these IBPs by factors of 2.2, 2.1, 6.8 and 2.3, respectively. No significant increase was found in estimates of the maximum P sorption capacity when further extending the equilibration time to 10 days. Conclusions: A minimum equilibration period of 5 days is recommended to avoid underestimating the maximum P sorption capacity of the IBPs examined in this paper. Each of the IBPs we evaluated was able to sorb P from solution, although with variable capacity (maximum sorption capacity after 5 days of equilibration ranged from 16.3-28.5 mg P g). These findings emphasise the importance of accurate quantification of the P sorption capacity of IBPs before application. [ABSTRACT FROM AUTHOR]

Using industrial by-products (IBPs) in conjunction with buffer strips provides a potentially new strategy for enhancing soluble phosphorus (P) removal from agricultural runoff. Here, we investigate the feasibility of this approach by assessing the P sorption properties of IBPs at different solution-IBPs contact time (1-120 min) and solution pH (3, 5.5, 7.5), as well as possible adverse environmental effects including P desorption or heavy metal mobilisation from IBPs. Batch experiments were carried out on two widely available IBPs in the UK that demonstrated high P sorption capacity but different physicochemical characteristics, specifically ochre and Aluminium (Al) based water treatment residuals (Al-WTR). A series of kinetic sorption-desorption experiments alongside kinetic modelling were used to understand the rate and the mechanisms of P removal across a range of reaction times. The results of the kinetic experiments indicated that P was initially sorbed rapidly to both ochre and Al-WTR, followed by a second phase characterised by a slower sorption rate. The excellent fits of kinetic sorption data to a pseudo-second order model for both materials suggested surface chemisorption as the rate-controlling mechanism. Neither ochre nor Al-WTR released substantial quantities of either P or heavy metals into solution, suggesting that they could be applied to buffer strip soils at recommended rates (≤30 g kg soil) without adverse environmental impact. Although the rate of P sorption by freshly-generated Al-WTR applied to buffer strips reduced following air-drying, this would not limit its practical application to buffer strips in the field if adequate contact time with runoff was provided. [ABSTRACT FROM AUTHOR]

In situ metal stabilisation by amendments has been demonstrated as an appealing low-cost remediation strategy for contaminated soil. This study investigated the short-term leaching behaviour and long-term stability of As and Cu in soil amended with coal fly ash and/or green waste compost. Locally abundant inorganic (limestone and bentonite) and carbonaceous (lignite) resources were also studied for comparison. Column leaching experiments revealed that coal fly ash outperformed limestone and bentonite amendments for As stabilisation. It also maintained the As stability under continuous leaching of acidic solution, which was potentially attributed to high-affinity adsorption, co-precipitation, and pozzolanic reaction of coal fly ash. However, Cu leaching in the column experiments could not be mitigated by any of these inorganic amendments, suggesting the need for co-addition of carbonaceous materials that provides strong chelation with oxygen-containing functional groups for Cu stabilisation. Green waste compost suppressed the Cu leaching more effectively than lignite due to the difference in chemical composition and dissolved organic matter. After 9-month soil incubation, coal fly ash was able to minimise the concentrations of As and Cu in the soil solution without the addition of carbonaceous materials. Nevertheless, leachability tests suggested that the provision of green waste compost and lignite augmented the simultaneous reduction of As and Cu leachability in a fairly aggressive leaching environment. These results highlight the importance of assessing stability and remobilisation of sequestered metals under varying environmental conditions for ensuring a plausible and enduring soil stabilisation. [ABSTRACT FROM AUTHOR]

This work outlines an integrated methodology for converting metallurgical by-products into high added value products, through an essentially zero-waste process. Thermodynamic modelling and conceptual design for processing bauxite residues (red mud) from the primary aluminium industry and ferro-nickel production slags are presented as examples. Furthermore, results of semi-industrial scale experiments for processing bauxite residues are illustrated, along with a preliminary financial analysis and an exergy flowsheet of the new conceptual alumina refinery, all confirming the financial viability as well as the resource-efficient utilization of the proposed technology. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to compare the effectiveness of chemical-enhanced soil washing (with chelating agents, humic substances and inorganic acids) and soil stabilisation by inorganic industrial by-products (coal fly ash, acid mine drainage sludge and zero-valent iron) and organic resource (lignite) for timber treatment site remediation. Materials and methods: Both remediation options were assessed in terms of extraction/leaching kinetics and residual leachability (toxicity characteristic leaching procedure, TCLP) of the major risk drivers, i.e. Cu and As. Results and discussion: In chemical-enhanced soil washing, chelating agents only minimised the Cu leachability. Humic substances were ineffective while inorganic acids reduced the As leachability to the detriment of the soil quality. For the waste-stabilised soil, the short-term leaching potential (72 h) and long-term TCLP leachability (9 months) revealed that Fe-/Al-/Ca-rich AMD sludge and coal fly ash sequestered As through adsorption and (co-)precipitation, while carbonaceous lignite stabilised Cu with oxygen-containing functional groups. The short-term and long-term leaching of Cu and As into the soil solution was negligible in the presence of the waste materials. However, the waste-stabilised soil did not maintain sufficient Cu stability in the TCLP tests, in which acetate buffer induced significant mineral dissolution of the waste materials. Conclusions: These results suggest that chelant-enhanced washing (significant reduction of Cu leachability) may be augmented with subsequent stabilisation with inorganic waste materials (effective control of As leachability), thus minimising the environmental risks of both Cu (heavy metal) and As (metalloid) while preserving the reuse value of the soil. Additional tests under field-relevant conditions are required to provide a holistic performance evaluation. [ABSTRACT FROM AUTHOR]

Highlights: [•] Use of industrial by-products i.e. bottom ash and waste foundry sand in concrete. [•] Microstructure analysis of concrete using XRD and SEM. [•] Mechanical and durability properties of concrete using industrial by-products. [Copyright &y& Elsevier]

Metallurgical iron sludge (MIS) is an industrial by-product that needs high value-added utilization without harmless to the environment. Here, α-Fe 2 O 3 nanoparticles were successfully prepared from MIS via a novel solvent-free method (SN-α-Fe 2 O 3) and applied to Cr(VI) ions removal. Compared to conventional methods using pure reagents, the as-prepared SN-α-Fe 2 O 3 aggregated into uniform cake-like mesoporous structures with a higher specific surface area (115.03 m2/g) and smaller crystal size (32.87 nm), thus providing a large number of active adsorption sites. Therefore, SN-α-Fe 2 O 3 exhibited superior Cr(VI) removal performance (removal efficiency 98.21%) in Cr(VI)-contaminated wastewater compared to previous studies. Furthermore, Cr(VI)-saturated SN-α-Fe 2 O 3 exhibited great stability under acidic conditions and maintained excellent adsorption performance after five cycles. The proposed SN-α-Fe 2 O 3 preparation process forwent the use of water solvent or organic solvents, thus improving reactor efficiency and avoiding wastewater generation. Particularly, the growth mechanism of SN-α-Fe 2 O 3 crystal followed the solid-phase transition mechanism, whereby small amounts of crystal water contained in pretreated MIS was sufficient for SN-α-Fe 2 O 3 crystallization. Furthermore, SN-α-Fe 2 O 3 -mediated Cr(VI) adsorption was attributed to the electrostatic interaction and reduction of hydroxyl group on the surface of SN-α-Fe 2 O 3. This study thus provides a win-win strategy for the conversion of industrial by-products into valuable nanoparticles for the cost-efficient treatment of heavy metal-polluted wastewater. [Display omitted] • Low-cost MIS was sustainably converted into high value-added α-Fe 2 O 3 nanoparticles. • The SN-α-Fe 2 O 3 preparation method improved efficiency without wastewater generation. • SN-α-Fe 2 O 3 provided many active adsorption sites due to its structural properties. • SN-α-Fe 2 O 3 exhibited great Cr(VI) removal efficiency (98.21%) at optimal pH (2.00). • SN-α-Fe 2 O 3 removed Cr(VI) via electrostatic interaction and OH group reduction. [ABSTRACT FROM AUTHOR]

Highlights: [•] AMD sludge effectively sequesters As and Cu in soil solution. [•] Advantage of co-addition of compost and lignite is manifested in TCLP tests. [•] Metal interactions with inorganic and carbonaceous materials are highlighted. [•] Continuous acid leaching leads to organic matter and mineral dissolution. [•] Engineering implications and recommendations are elaborated for field deployment. [Copyright &y& Elsevier]

Highlights: [•] An activated carbon is synthesized starting from coal tar pitch and furfural. [•] Physical and chemical properties of the solid are suitable for CO2 adsorption. [•] The effects of temperature, concentration and flow rate on CO2 adsorption are analyzed. [•] The activated carbon can be used within 15 consecutive adsorption–desorption cycles. [•] The optimal operating conditions for CO2 recovery by desorption are defined. [Copyright &y& Elsevier]

Abstract: Biodiesel production from high acidity industrial by-products was studied using heterogeneous acid catalysts. These by-products contain 26–39% of free fatty acids, 45–66% of fatty acids methyl esters and 0.6–1.1% of water and are consequently inadequate for direct basic catalyzed transesterification. Macroporous vanadyl phosphate catalysts with V/P=1 (atomic ratio) prepared via sol–gel like technique was used as catalyst and it was possible to produce in one reaction batch a biodiesel contain 87% and 94% of FAME, depending on the by-product used as raw material. The initial FAME content in the by-products had a beneficial effect on the reactions because they act as a co-solvent, thus improving the miscibility of the reaction mixture components. The water formed during esterification process seems to hinder the esters formation, possibly due to competitive adsorption with methanol and to the promotion of the FAME hydrolysis reaction.The observed catalyst deactivation seems to be related to the reduction of vanadium species. However, spent catalysts can be regenerated, even partially, by reoxidation of the reduced vanadium species with air. [Copyright &y& Elsevier]

Agricultural drainage ditches provide a direct pathway for high nutrient loads such as phosphorus (P) from fields to surface waters. Most practices designed to reduce P loading from fields focus on overland flow and sediment-bound P; however, P transport in these landscapes can be dominated by subsurface transport of dissolved P. Filters have been designed and are currently being field-tested that utilize P sorbing materials to remove P directly from flow in ditches. Models have been developed to predict P removal and the time of filter effectiveness. While filter performance along with model development and validation is examined in separate papers, there is a need to translate these models into usable tools for watershed managers who have to decide on filter design. This study provides examples of how these models can be used to design P-removal structures containing electric arc furnace slag (EAFS) or flue gas desulphurization gypsum (FGDG). Through the use of realistic parameters for retention time, inflow P concentration and material characteristics, the presented examples demonstrate that EAFS would outperform FGDG across a range of inflow P concentrations (0.5-10 mg/L) and removing 28-65% more P. With an average inflow P concentration of 1.62 mg/L (typical for ditches on the Delmarva Peninsula, United States), a 20-Mg EAFS filter would remove 42% more P than a 31-Mg FGDG filter. In addition, the EAFS filter would have a flow rate 10 times that of the FGDG filter. The predictive equations discussed in this paper can be used to determine the cost per unit of P removed of filters containing different materials. [ABSTRACT FROM AUTHOR]

Abstract: Wheat germ and corn bran are by-products derived from the bread baking industry. This study aims to development of efficient and low cost processing methods to transform these residues in added value co-products. The basic chemical composition analyses revealed high values of dry matter (87.5–89.8g/100g FW), significant amounts of total ash (13.3–18.0g/100g FW) content and low fat contents (2.2–9.8g/100g FW). The starch values found in the original samples were much lower than after the sequential defatting method revealing a content of starch 3.39, 3.44 and 3.27-fold higher for the samples of wheat germ, maize flour of zootechnical grade and fine, respectively. The performed stabilization studies revealed significant increases up to week 3 in the total phenolics content of the wheat germ and maize cell wall samples. Within the low molecular weight phenolics, quercetin was the major compound (47.3mg/100g FW), in the cell wall of wheat germ samples. The antioxidant activity showed significant differences between liquid and solid fractions, with the highest values (0.38μmol/L Trolox Eq. FW) in the wheat germ liquid fraction. The results show that these by-products can be used as a source of bioactive compounds beneficial for health, while the method used for starch “enrichment” may potentially transform the fine maize flour into an added value co-product. [Copyright &y& Elsevier]

Abstract: A series of incubation and leaching experiments were performed to assess the feasibility of three industrial by-products (red gypsum (RG), sugar foam (SF) and ashes from the combustion of biomass (ACB)) to reduce the leachability of Cu, Pb, Zn and As in a sediment of São Domingos mine (Portugal). The changes in the element solid phase speciation were also evaluated by applying a sequential extraction procedure. All amendments significantly reduced the leachability of Zn and Cu, whereas the treatment with RG+SF+ACB also decreased the mobility of As. The reduction in Cu leachability was especially remarkable. This could be due to the great affinity of carbonates (included in SF and SF+ACB amendments) to precipitate with Cu, and maghemite and rutile (RG amendment) for acting as relevant sorbents for Cu. Pb was the least mobile element in the sediment and none of the treatments reduced its mobility. The sequential extraction reveals that the amendments induced a significant decrease in the concentration of elements associated with the residual fraction. Cu, Pb and As are redistributed from the residual fraction to the Al, Fe, and Mn hydr(oxides) fraction and Zn from the residual fraction to the water/acid soluble, exchangeable and bound to carbonates pool. [Copyright &y& Elsevier]

A field experiment evaluated the effects of surface applications of two industrial by-products (sugar foam and phosphogypsum) to an acidic Ultisol of the temperate zone in Spain to ameliorate topsoil and subsurface acidity and potential aluminium (Al) toxicity. The by-products were applied in single and combined amendments and at two different rates. Two years after their application, it was determined that applications at a low rate of sugar foam and sugar foam + phosphogypsum increased the pH and the exchangeable calcium (Ca) and reduced the exchangeable Al in the surface horizon of the soil while only a significant reduction of exchangeable Al was obtained in the subsurface horizon. Long-term amelioration of acidity and potential Al toxicity were only achieved upon the addition of these treatments at high rate. The addition of sugar foam at a high rate provides an effective practice for long-term acidity amelioration from the surface downward. [ABSTRACT FROM PUBLISHER]

Abstract: Norwegian industrial tailings and by-products, as well as naturally occurring minerals and ores have been surveyed with the purpose of identifying candidate oxygen carrier materials for use in a chemical looping combustion process. Nine materials, based on manganese and/or iron oxide, were selected for an initial screening test; six were deemed promising and were hence investigated further. Thermogravimetric experiments were performed to investigate the oxygen capacity, the reaction kinetics and reversibility of the oxygen absorption reaction. A manganese ore with a reversible capacity of 4.9wt% oxygen at 1000°C was selected as the most promising for chemical looping combustion applications. This material was modified by addition of calcia to explore the possibility of enhancing the kinetic, catalytic and mechanical properties. The addition of excess calcium relative to manganese resulted in formation of calcium manganite and related phases. The oxygen capacity of the modified material was 4.5wt% at 1000°C, but it has potential advantages in terms of kinetics and chemical and mechanical stability relative to the pure ore. [Copyright &y& Elsevier]

The potential of six industrial by-products for use as phosphorus-sorbing materials (PSMs) in solutions was evaluated. These included two different acid mine drainage treatment residuals (AMDR1 and AMDR2), water treatment residual (WTR), fly ash, bauxite mining residual, and flue gas desulfurization product (FGD). Characterization of the by-products and their mechanisms for sorption and retention of inorganic phosphorus (P) from solution identified those PSMs that sorbed primarily by an iron and aluminum (Fe/Al) mechanism, those that sorbed primarily by a calcium and magnesium (Ca/Mg) mechanism, and those that sorbed by both mechanisms. Degree of P sorption and associated mechanisms were strongly influenced by the pH, buffer capacity, ionic strength, and common ion effects. [ABSTRACT FROM AUTHOR]

Abstract: An experimental investigation was conducted to study the effect of using copper slag as a fine aggregate on the properties of cement mortars and concrete. Various mortar and concrete mixtures were prepared with different proportions of copper slag ranging from 0% (for the control mixture) to 100% as fine aggregates replacement. Cement mortar mixtures were evaluated for compressive strength, whereas concrete mixtures were evaluated for workability, density, compressive strength, tensile strength, flexural strength and durability. The results obtained for cement mortars revealed that all mixtures with different copper slag proportions yielded comparable or higher compressive strength than that of the control mixture. Also, there was more than 70% improvement in the compressive strength of mortars with 50% copper slag substitution in comparison with the control mixture. The results obtained for concrete indicated that there is a slight increase in density of nearly 5% as copper slag content increases, whereas the workability increased significantly as copper slag percentage increased compared with the control mixture. A substitution of up to 40–50% copper slag as a sand replacement yielded comparable strength to that of the control mixture. However, addition of more copper slag resulted in strength reduction due to the increase in the free water content in the mix. Also, the results demonstrated that surface water absorption decreased as copper slag content increases up to 50% replacement. Beyond that, the absorption rate increased rapidly and the percentage volume of the permeable voids was comparable to the control mixture. Therefore, it is recommended that up to 40–50% (by weight of sand) of copper slag can be used as a replacement for fine aggregates in order to obtain a concrete with good strength and durability requirements. [ABSTRACT FROM AUTHOR]

Abstract: The production of a high-strength, high performance concrete using high volumes of industrial by-products is tested in laboratory mixtures. The by-products used are high-calcium fly ash and ladle furnace slag as binders and electric arc furnace slag as aggregates. Fly ash is used as 50% by mass of the total binder and ladle furnace slag as 30% by mass of the total binder. Slag aggregates are used in replacement of coarse aggregate or in replacement of both fine and coarse aggregates. In the mixtures containing both supplementary cementitious materials and slag aggregates the produced concrete shows high-strength (>70MPa), good abrasion resistance and fracture toughness. [Copyright &y& Elsevier]

Abstract: This study evaluates the potential use of four industrial by-products (phosphogypsum (PG), red gypsum (RG), sugar foam (SF), and ashes from biomass combustion (ACB)), applied at two rates in single and combined amendments to reduce the mobility and availability of Pb, Zn and Ni in a metal-spiked acid soil. Leaching experiments were done to estimate leachability indexes and assess their effectiveness. Most of the treatments significantly reduced the metal leachability although only a few were effective for all metals. Based on principal component and cluster analysis, sugar foam (SF) and a mixture of RG and ACB (RG+ACB), both applied at high rate, were selected as first choices to reduce mobility and availability of the three metals. Metal sorption mechanisms involved in the reduction of their leachability were identified using scanning electron microscopy. In the SF-treated samples, the metals were found associated to amorphous Al-hydroxy polymers deposited on phyllosilicates and organic matter particles. In the (RG+ACB)-treated samples, Pb, Zn, and traces of Ni were found associated to Fe/Ti oxide phases with a significant concentration of S, suggesting the formation of metal-sulfate ternary complexes. [Copyright &y& Elsevier]

Abstract: Four industrial by-products (phosphogypsum, PG; red gypsum, RG; sugar foam, SF and ashes from the combustion of biomass, ACB) were evaluated as possible amendments for reducing the leachability and bioavailability of As and Se in a metalloid-spiked acidic soil. The treatments were applied as single, double and triple amendments and at two different rates. The effectiveness of the treatments was evaluated after a series of leaching experiments using a chelating agent (DTPA solution) or a weak acidification (acetic acid at pH 4.93). The most effective treatments (ACB and RG, both applied at high rate) were identified by means of Cluster Analysis using the leachability indexes. Different sorption mechanisms involved in the overall reduction of metalloid leachability were identified using scanning electron microscopy (SEM-BSE and SEM-EDS). In the ACB-treated samples, Se was found associated to organic matter aggregates and to Fe compounds. In the RG-treated samples, EDS analyses showed that As and Se were associated to Fe/Ti (hydr)oxides phases which are present not only in the by-product as maghemite and rutile, but also in the soil as hematite and goethite. In addition, the application of RG induced the formation of non-crystalline Al-hydroxy polymers with As and Se in their composition. [Copyright &y& Elsevier]

Abstract: This paper reports on an experimental program to investigate the effect of using copper slag as a replacement of sand on the properties of high performance concrete (HPC). Eight concrete mixtures were prepared with different proportions of copper slag ranging from 0% (for the control mix) to 100%. Concrete mixes were evaluated for workability, density, compressive strength, tensile strength, flexural strength and durability. The results indicate that there is a slight increase in the HPC density of nearly 5% with the increase of copper slag content, whereas the workability increased rapidly with increases in copper slag percentage. Addition of up to 50% of copper slag as sand replacement yielded comparable strength with that of the control mix. However, further additions of copper slag caused reduction in the strength due to an increase of the free water content in the mix. Mixes with 80% and 100% copper slag replacement gave the lowest compressive strength value of approximately 80MPa, which is almost 16% lower than the strength of the control mix. The results also demonstrated that the surface water absorption decreased as copper slag quantity increases up to 40% replacement; beyond that level of replacement, the absorption rate increases rapidly. Therefore, it is recommended that 40wt% of copper slag can used as replacement of sand in order to obtain HPC with good strength and durability properties. [Copyright &y& Elsevier]

Abstract: This research study was conducted to investigate the performance of high strength concrete (HSC) made with copper slag as a fine aggregate at constant workability and to study the effect of superplasticizer addition on the properties of HSC made with copper slag. Two series of concrete mixtures were prepared with different proportions of copper slag. The first series consisted of six concrete mixtures prepared with different proportions of copper slag at constant workability. The water content was adjusted in each mixture in order to achieve the same workability as that for the control mixture. Twelve concrete mixtures were prepared in the second series. Only the first mixture was prepared using superplasticizer whereas the other eleven mixtures were prepared without using superplasticizer and with different proportions of copper slag used as sand replacement. The results indicated that the water demand reduced by almost 22% at 100% copper slag replacement compared to the control mixture. The strength and durability of HSC were generally improved with the increase of copper slag content in the concrete mixture. However, the strength and durability characteristics of HSC were adversely affected by the absence of the superplasticizer from the concrete paste despite the improvement in the concrete strength with the increase of copper content. All concrete mixtures did not meet the strength and durability design requirements due to the segregation and dryness of the concrete paste. Therefore it can be concluded that the use of copper slag as sand substitution improves HSC strength and durability characteristics at same workability while superplasticizer is very important ingredient in HSC made with copper slag in order to provide good workability and better consistency for the concrete matrix. [Copyright &y& Elsevier]

• This review article discusses utilization of various industrial by-products in developing CLSM. • Various industrial by-products that can be potentially used have been identified. • Parameters influencing the fresh and hardened properties of CLSM have been presented. • Suitable mix proportion for a particular industrial waste is possible to produce sustainable CLSM. • Several other waste materials that can be potentially useful are being identified. Disposal of industrial by-products and waste materials in the landfills is posing environmental pollution apart from incurring huge economical cost. Some of these materials could be effectively used in developing structural and non-structural cementitious materials. There are several non-structural applications of concrete, such as filling construction cavities and blinding concrete under the structural members, which requires low to very low strength concrete known as controlled low strength material (CLSM). In a move towards reducing greenhouse gasses generated by the production of cement and effectively using industrial by-products, several natural and waste materials are being utilized in the production of CLSM as a partial replacement of cement and aggregate. These include fly ash, natural pozzolan, silica fume, ground granulated blast furnace slag (GGBFS) and a host of other industrial wastes. In the recent past, the use of CLSM as a cost effective, as well as labor and timesaving alternative for compacted earth backfill has grown substantially. This article presents a review on the utilization of various industrial by-products for the development of CLSM and their influence on the fresh and hardened properties. Although several industrial by products have been used in the production of CLSM, fly ash has been extensively utilized for this purpose with great success due to its favorable morphology that is beneficial in obtaining feasible fresh and hardened properties. The results of various studies demonstrate that the type of industrial waste in the development of CLSM as both partial replacement of cement or aggregate and mix proportion greatly influences the fresh and hardened characteristics of CLSM. A suitable mix proportion for a particular industrial waste is possible to produce sustainable CLSM with desired properties. The review also identifies several other industrial waste materials that can incorporated for developing sustainable CLSM such as construction and demolition waste. Further, a comprehensive analysis of influence of various parameters on the properties of CLSM in this review possibly will form a basis for future research in this area for sustainable development in the prevailing environmental crises. [ABSTRACT FROM AUTHOR]

Abstract: The advantages of utilization of coal fly ash, phosphogypsum and some other industrial by-products in construction are discussed, as well as the technological and environmental problems caused by an elevated content of chemical/radioactive contaminants. Radiological aspects and legislation issues are analyzed. The tendency to develop stricter environmental norms observed in the last years in both national and international scale is noted. The reasons and possible methods of solving the difficulties with the application of legislation rules and radiation controls in construction industry are discussed. As an example, an experience with the new Israeli Standard 5098 regulating radioactivity in building products is reported. The principles of this standard are analyzed and compared to the Radiological Protection Principles Concerning the Natural Radioactivity of Building Materials Principles of Radiation (Radiological Protection Principles Concerning the Natural Radioactivity of Building Materials, Radiation Protection Report RP-112, EC, European Commission, Luxembourg, 1999) and other existing national standards and guidelines in the field. [Copyright &y& Elsevier]

Abstract: A novel MgO-type expansive agent in a designed formula has been prepared with industrial by-products—magnesite, serpentine and dolomite calcined at 1150°C for 1h. The compositions of expansive agent were studied by X-ray diffractometry (XRD), DSC and scanning electron microscopy (SEM), and the results showed that the main phases were MgO, CaO and C2S. The hydration of CaO to Ca(OH)2 is quick and can be completed in 3 days in water at 20°C, and MgO to Mg(OH)2 is slow and about 57% MgO hydrates into Mg(OH)2 in 180 days under the same condition, which is quicker than in water. The hydrations of CaO and MgO generate expansions in early and later age, respectively. The shrinkage of roller compacted concrete will be compensated by adding the expansive agent. The utilization of these industrial by-products in the construction of hydraulic dams not only compensates the shrinkage of dam, but also reduces the environmental pollution. [Copyright &y& Elsevier]

In this study, physicomechanical characterization is evaluated using ultrasonic pulse–echo measurements through high-volume fly ash (HVFA) cement paste. The composites were tested at different water-content levels to infer their influence on the pulse–echo measurements. To achieve different water content levels, samples were dried in an oven between 60 and 105°C at 6-, 12-, and 24-h intervals. Physical (dry unit weight, apparent specific gravity, porosity at 7 and 28 days) and mechanical (unconfined compression test at 7 and 28 days) measures were performed.The research indicates that the degree of saturation significantly affects the ultrasonic pulse–echo of HVFA cement paste. The empirical relations of the physical and mechanical properties with ultrasonic pulse velocity are highly correlated. [ABSTRACT FROM AUTHOR]

Abstract: A large number of substrates potential for removal of phosphorus (P) in wastewater has been reviewed. The substrates consist of natural materials, industrial by-products and man-made products. Most substrates have been investigated in batch and column studies in the laboratory; others have also been tested in field trials. The results from these investigations vary, but a few substrates, e.g. wollastonite, slag material and, to some extent, light weight aggregate products, have demonstrated promising properties with regard to P-sorption capacity and hydraulics. The problems of normalisation of data are discussed, as well as the substrates potential benefits for on-site wastewater treatment. [Copyright &y& Elsevier]

Abstract: The present work studies the use of clays like high reactivity metakaolin, as pozzolans for concrete. This study adopted two clay types: kaolinite and kaolin by-products from the paper industry. In this second clay, besides the possible technical advantages, the ecological benefit of the use of a by-product must be considered. Initially, the chemical and mineralogical characteristics of the clays were determined. After this, calcination and milling was carried out aiming at obtaining materials with pozzolanic activity. After milling took place in the clays kaolinite and in the by-products, with the best physical characteristics, lab tests were carried out to verify the pozzolanic activity of these materials with Portland cement and with lime. The results show a low performance of the kaolinite and a high performance of the by-products industrial. The low performance of the kaolinite was credited to the lack of homogeneity of the calcination, as the material was obtained after the calcination, and the low efficiency of its milling process. [Copyright &y& Elsevier]

• Extreme vertices design is adopted to represent the experimental space. • The suitability of composites is investigated based on UCS and W/D durability tests. • The effect of each mixture component and their interactions are established. • Fly ash acts on UCS as a filler in the short term and as a reactant in the long term. • A negative impact of excess lime on strength and durability is highlighted. This paper investigates the valorization of phosphogypsum and fly ash by-products as a road construction material through lime stabilization. To this end, an extreme vertices design was adopted to model the compaction characteristics, mechanical performance at different curing periods and durability upon wetting/drying (W/D) cycles of the mixture. Statistical analysis of the obtained regression models showed that the measured responses decrease with phosphogypsum addition while fly ash and lime cause them to increase. The increasing effect of fly ash addition was especially noticeable on compressive strengths at early ages (7–28 days), whereas at longer curing periods (90–360 days), these were mainly governed by its interaction with lime following the activation of the pozzolanic reaction where phosphogypsum acted as a catalyst to improve fly ash reactivity. However, a negative impact of excess lime beyond a threshold has been noted. The compressive strength at 28 days combined with weight loss upon W/D cycles were used as optimization responses to detect regions of interest, within the design space, where requirements are met for a subbase utilization. [ABSTRACT FROM AUTHOR]

This work investigated the effects of feeding ensiled bergamot pulp to pigs on meat and salami quality. Eighteen pigs were assigned to two experimental treatments and fed a cereal-based concentrate diet (control) or the same diet in which ensiled bergamot pulp replaced 15% dry matter of the diet fed (BP). The BP treatment increased α-linolenic acid (+250%; P < 0.05), docosapentaenoic acid (+62%; P < 0.05), docosahexaenoic acid (+43%; P < 0.05) and consequently n-3 PUFA (+15%; P < 0.01) in meat. In salami, the content of α-linolenic acid, total PUFA and n-3 PUFA increased (+320%, +25% and + 258%, respectively) by feeding the BP diet (P < 0.001). The inclusion of bergamot pulp in the diet did not alter the oxidative stability in raw and cooked meat and colour descriptors. In salami, TBARS values were lower after 5 days of storage (P < 0.001) in BP group (1.54 vs 2.96). Finally, dietary supplementation with ensiled bergamot pulp to pigs improved the nutritional value of meat and meat products. • Bergamot pulp in pigs diet increases the contents of α-linolenic acid in meat. • Bergamot pulp positively affected meat and salami fatty acid composition. • Inclusion of 15% of bergamot pulp does not compromise animal performances. • The integration of bergamot pulp reduced lipid oxidation in salami. [ABSTRACT FROM AUTHOR]

[Display omitted] • Area of bloating clays by Riley and Wilson is used to assess the bloatablity of CDW to make LWA. • Brick and fly ash in Vietnam is suitable for producing LWAs, GBFS is not. • SiC is suitable as a blowing agent to produce LWAs from CDW and fly ash. • Optimum sintering temperature to make LWA from CDW is 1220–1250 °C. • Necessary residence time for burning is 6–9 min. The amount of construction and demolition waste and industrial by-products are increasingly high in Vietnam recently. The recycling of these wastes as new construction materials is an effective solution for sustainable development. This paper presents a method for the recycling of construction and demolition waste and other industrial by-products, such as fly ash and slag in Vietnam to produce lightweight aggregate. Experimental results show that masonry wastes including brick and mortar as well as fly ash are suitable materials for producing lightweight aggregates with a granule density of less than 1000 kg/m3 with the optimum sintering temperatures and the residence time in the range from 1220 °C to 1250 °C and, 6 to 9 min, respectively. These recycled lightweight aggregates can be used as valuable substitutes for natural aggregates to make lightweight concrete for new structures and therefore contribute to the construction industry's sustainability. [ABSTRACT FROM AUTHOR]