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To solve the problem of low cementitious activity of steel slag (SS), N, N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid sodium salt (BES-Na) and triethanolamine (TEA) were used in this study to improve the hydration activity of SS. However, there are no comparative studies on the effects of BES-Na and TEA on the hydration of SS-Portland cement (PC) systems. This study compared the hydration process and strength development of SS-PC systems in the presence of BES-Na and TEA, as well as the complexing ability of BES-Na and TEA. The results showed that both BES-Na and TEA improved the early compressive strength of SS-PC mortar, but TEA did not contribute to the late compressive strength, while BES-Na still improved the late compressive strength. At the same dosage, TEA accelerated aluminates hydration more than BES-Na and retarded/inhibited silicates hydration more than BES-Na. This difference in effect on hydration can be attributed to the difference in their complexing ability. TEA has a stronger complexing ability with metal ions than BES-Na, which is beneficial for accelerating aluminates hydration, but this not only prolonged the hydration induction period but also inhibited silicates hydration. BES-Na has a weaker complexing ability relative to TEA. Although BES-Na has a weaker accelerating effect on aluminates hydration, it has a lesser effect on silicates hydration and even accelerates silicates hydration at low dosage. This study also showed that BES-Na is an alternative additive to TEA, which could help expand the application of BES-Na in cementitious materials.

This study proposes an effective machine learning-based prediction method to satisfy the urgent requirement to anticipate the mechanical properties of 3D-printed concrete. The goal is to support the accurate use of 3D printing technology in the building sector. We have successfully created machine learning models that can predict compressive strength and flexural strength by combining experimental data from a variety of 3D printed concrete samples and carefully preparing the data. Our study explores the fundamentals and practicality of several models, such as artificial neural networks, decision trees, random forests, support vector regression, and linear regression. We have made sure that our prediction findings are reliable and scientifically sound by implementing stringent model training and validation procedures. With a correlation coefficient between 0.96 and 0.98 with real values, experimental results demonstrate the random forest model's remarkable predicted accuracy, greatly beyond that of conventional prediction techniques. The practical use of 3D printed concrete in engineering projects is strengthened by this work, which also opens up new avenues for investigation and highlights the enormous potential of machine learning to improve the prediction of mechanical properties of building materials.

This study aims to achieve further progress in application performance of polymers in cement-based materials. The objective is to establish the research direction of superplasticizers with ordered micro-sequence via the innovation of synthesis technology and to clarify the correlation between the specific motifs in the microstructures of superplasticizers and the properties of cement pastes. In this study, a novel comb-like polycarboxylate superplasticizer (PCE) was synthesized using isobutenyl polyethylene glycol (IPEG) and hydroxyethyl acrylate (HEA) by atom transfer radical polymerization (ATRP) (defined as A-CPCE). Comb-like PCE with the same molecular weight as A-CPCE was also produced via conventional free radical polymerization (defined as CPCE). The molecular properties of both polymers and the structural motifs of monomers therein were characterized via size exclusion chromatography (SEC), 1H nuclear magnetic resonance (1H NMR), 13C nuclear magnetic resonance (13C NMR) and MATLAB, and furthermore the adsorption behavior of PCE polymers on cement particles was analyzed. Together with the rheological and mechanical properties of cement-based materials, the relationship between micro-sequence distribution and macro-performance of PCEs was investigated. The results showed that the monomer sequence distribution in A-CPCE was AAE and AAA, and the probability of the acid-ether ratio of 4:1 was 16.54%, meaning that relatively uniform polymer species were obtained. The A-CPCE molecules exhibited the smaller hydrodynamic radius (Rh=11.7 nm) and stronger adsorption capacity (maximum was 2.3618 mg·g−1) in cement pastes, which was in good accordance with Langmuir isotherm model and pseudo-second order kinetic model. The dispersing power of PCEs correlated with the specific motifs in the microstructures, thus indicating that A-CPCE enhanced the rheological performances of cement paste and concrete. In addition, the compressive strengths of concrete containing A-CPCE after 3 d, 7 d and 28 d were 16.00 MPa, 28.30 MPa and 52.9 MPa, respectively, which were significantly higher than those of concrete with CPCE.

Hydraulic lime has been successfully applied to repair masonry/geotechnical ancient architecture. However, chemical pollutants caused by modern industrial development have enriched the building base for a long time, and the mechanism by which corrosive media destroy the hydraulic lime repair material is unclear. In this study, the properties and structural failure of natural hydraulic lime (NHL) and metakaolin-air lime (MK-AL) due to NaOH, NaCl and Na2SO4 erosion were studied in terms of macroscopic variation, mechanical property deterioration and internal three-dimensional (3D) structure evolution. The results obtained by XRD, TG-DTA and MIP tests show that the hardening products and pore structure composition of NHL and MK20AL pastes were significantly different, which led to different erosion resistances. Based on the apparent morphology and X-CT test, no cracks were formed in the macroscopic structure of NHL and MK20AL mortar by NaOH and NaCl erosion after different periods. The mechanical strength of NHL mortar showed little change after erosion by the above two media. For the MK20AL mortar, the compressive strength increased by NaOH erosion and the flexural strength decreased significantly by NaCl erosion. No clear expansion cracks formed in the surface and internal structure of NHL mortar by Na2SO4 erosion, and the compressive strength increased by ∼20%. Gypsum erosion and secondary erosion (gypsum and C-A-H reaction to generate ettringite) formed in MK20AL mortar by a Na2SO4 medium. Additionally, volume expansion of solid phase (corrosion product) caused crack to form in the internal mortar structure, the cracks gradually became wider, and a crack network formed with the extension of erosion; thus, the internal structure and mechanical properties were seriously damaged. Overall, compared to the MK20AL mortar, the NHL mortar shows better resistance to erosion by environmental media, and NHL is the better choice for restoring ancient buildings and plastering mortar projects. The resistance of MK20AL to erosion by mortar environmental media needs to be optimized and modified.

In order to explore the antioxidant effect of the British red kidney bean antioxidant peptide components, ultrafiltration and dextran gel G-15 chromatography technology were used to classify the antioxidant products prepared by alkaline protease enzymatic hydrolysis of the British red kidney bean antioxidant protein, and the effect of components with higher antioxidant activity on PC12 cells damaged by H2O2 was studied. The results showed that the antioxidant peptide component BRKBAPC-2 could alleviate the cell growth inhibitory effect of H2O2 on PC12. With the increasing of peptide concentration, the level of intracellular reactive oxygen species (ROS) levels, malondialdehyde (MDA) content and lactate dehydrogenase (LDH) extracellular activity were all reduced, the activity of superoxide dismutase (SOD), catalase (CAT) and the content of reduced glutathione (GSH) were all increased, especially when the concentration of BRKBAPC-2 was 200 μg/mL, ROS level was 32.53%, MDA content was 0.96 nmol/μg prot, LDH extracellular activity was 202.12 U/L, compared with the model group, they were significantly reduced (P

In order to explore the antioxidant effects of the British red kidney bean protein antioxidant peptide components and their effects on soybean oil thermal stability, the antioxidant peptides components of different molecular weights were added to the soybean oil and oxidized by Schaal oven method at 63 ℃ for 15 day. The effects of antioxidant peptides on the peroxide value, acid value, p-anisylamine, carbonyl value indexes of soybean oil were studied, and the oxidation stability of soybean oil was evaluated. The results showed that, from 0 to 15 day, the peroxide values of SO (peptide-free oil), SO-h1 (oil containing peptide less than 1000 Da) and SO-h2 (oil containing 1000~3000 Da peptide) increased from 0.50 to 2.91, 1.48 and 1.57 mmol/kg, respectively, the acid value increased from 0.19 to 0.41, 0.37 and 0.38 mg/kg, the p-anisidine value increased from 2.34 to 9.96, 8.06 and 9.75 mg/kg, and the carbonyl value increased from 5.59 to 14.53, 11.87 and 11.92 meq/kg, respectively. The increasing range of SO was the largest, and the increasing range of SO-h1 was the smallest, and the above results were significantly different (P

Flame retardant modification of leaf fibers was carried out to solve the technical problem of poor fire resistance of plant fibers and improve the utilization rate of urban fallen leaves in building materials. The modification scheme adopts three flame retardants, i.e., ammonium polyphosphate (APP), magnesium hydroxide (MH), and aluminum hydroxide (ATH), and two covering layers, i.e., pure acrylic polymer lotion and water glass (Na2O · nSiO2) solution. The modified leaf fiber's combustion behavior and pyrolysis properties were tested and analyzed. The physical and mechanical characteristics, as well as the thermal insulation qualities, of leaf fiber cement-based composites (LFCC) were studied at high temperatures. The findings revealed that the three flame retardants had an effect on the chemical structure of leaf fibers. In comparison to leaf fibers without flame-retardant modification, flame-retardant-modified leaf fibers have a much greater thermal stability. and its LOI is greater than 27.0%, which is a fire-retardant material. Except for the sample with water glass as the modified cover layer, at high temperatures, the composite flame-retardant fiber LFCC's mass-loss rate is lower compared with fibers without flame-retardant modification or fibers modified with only one kind of flame-retardant. In the composite flame-retardant modified fiber LFCC, the samples with better strength at high temperature are those with ATH replacing 30% and 50% MH. The thermal conductivity of LFCC is negatively correlated with the range of temperature change.

To solve the poor fireproof performance of plant fibers, one of the technical difficulties, and use more straw fibers as construction materials, wheat straw fibers (WSFs) have been subject to flame-retardant modification. Then, tests and analysis over the modified WSFs per the burning behavior and pyrolysis performance have been made. The physical and mechanical, and thermal insulation properties of wheat straw fiber cement-based composites (WSFCC) at high temperatures were characterized. The results are as follows: Ammonium polyphosphate (APP), magnesium hydroxide (MH), and aluminum hydroxide (ATH), three fire retardants, all affect the chemical structure of WSFs. P, Mg, and Al elements of the three retardants are successfully adsorbed onto the fibers' surface subject to modification. Flame-retardant WSFs significantly outperforms the non-flame-retardant ones per thermostability and flame retardancy. The heat release rate (HRR), total heat release (THR), effective heat of combustion (EHC), and mass loss rate (MLR) of most flame-retardant WSFs are obviously lower than those of non-flame-retardant ones. The APP-modified WSFs demonstrate higher total smoke production (TSP), while WSFs modified with composite flame retardants perform better in flame retardancy and smoke suppression. The MLR of WSFCC at high-temperature increases as the temperature goes higher. The compressive and flexural strengths of WSFCC decrease with the increase of temperature and the decrease mitigates after 350 °C. In terms of thermal conductivity, composite-flame-retardant fiber WSFCC are much higher than non-flame-retardant fiber and APP-modified fiber WSFCC. As the temperature rises, the thermal conductivity of composite-flame-retardant fiber WSFCC tends to decrease.

To improve the resource level of agricultural and forestry waste straws and fallen leaves, straw and fallen leaves fibres were used as organic thermal insulation components (TICs). Vitrified beads and closed-pore expanded perlite were used as inorganic TICs to prepare plant fibre cement-based composite thermal insulation mortar (TIM). The effects of TICs on physical and mechanical properties of TIM were studied by altering the types and contents of TICs. The results show that the fluidity of the TIM decreases with the incorporation of plant fibres in the vitrified bead + expanded perlite TIM. With the addition of wheat straw fibre and straw fibre, the homogeneity of TIM mixture is improved. Plant fibres have the characteristics of lightweight, porosity, water absorption and heat preservation, which increases water absorption and heat retention and a decrease in strength of the TIM. With the incorporation of three plant fibres of leaves, wheat straw and straw, the water absorption of TIM increased by 15.84, 5.47, and 4.54% respectively. At the same time, thermal conductivity decreased by 0.17, 0.19, and 0.20 W/(m.K), respectively, flexural strength decreased by 3.99, 2.63, and 2.44 MPa, and compressive strength decreased by 20.91, 17.13, and 19.25 MPa, respectively. After the expanded perlite and vitrified microbeads are modified with pure acrylic emulsion, the polymer film retains more pores inside the fibres, enhances the interface bonding with the cement-based material, which is helpful to improve the thermal insulation properties and strength of the TIM.

In order to understand the mechanisms of arsenic (As) accumulation and detoxification in aquatic plants exposed to different As species, a hydroponic experiment was conducted and the three aquatic plants (Hydrilla verticillata, Pistia stratiotes and Eichhornia crassipes) were exposed to different concentrations of As(III), As(V) and dimethylarsinate (DMA) for 10 days. The biomass, the surface As adsorption and total As adsorption of three plants were determined. Furthermore, As speciation in the culture solution and plant body, as well as the arsenate reductase (AR) activities of roots and shoots, were also analyzed. The results showed that the surface As adsorption of plants was far less than total As absorption. Compared to As(V), the plants showed a lower DMA accumulation. P. stratiotes showed the highest accumulation of inorganic arsenic but E. crassipes showed the lowest at the same As treatment. E. crassipes showed a strong ability to accumulate DMA. Results from As speciation analysis in culture solution showed that As(III) was transformed to As(V) in all As(III) treatments, and the oxidation rates followed as the sequence of H. verticillata>P. stratiotes>E. crassipes>no plant. As(III) was the predominant species in both roots (39.4–88.3%) and shoots (39–86%) of As(III)-exposed plants. As(V) and As(III) were the predominant species in roots (37–94%) and shoots (31.1–85.6%) in As(V)-exposed plants, respectively. DMA was the predominant species in both roots (23.46–100%) and shoots (72.6–100%) in DMA-exposed plants. The As(III) contents and AR activities in the roots of P. stratiotes and in the shoots of H. verticillata were significantly increased when exposed to 1 mg·L-1 or 3 mg·L-1 As(V). Therefore, As accumulation mainly occurred via biological uptake rather than physicochemical adsorption, and AR played an important role in As detoxification in aquatic plants. In the case of As(V)-exposed plants, their As tolerance was attributed to the increase of AR activities.

As a kind of volatile organic compound (VOC), methyl tert-butyl ether (MTBE) is hazardous to human health and destructive to the environment if not handled properly. MTBE should be removed before the release of wastewater. The present work supported the methyl-modified silica layer (MSL) on porous α-Al2O3 ceramic membranes with methyltrimethoxysilane (MTMS) as a precursor and pre-synthesized mesoporous silica microspheres as dopants by the sol-gel reaction and dip-coating method. MTMS is an environmentally friendly agent compared to fluorinated alkylsilane. The MSL-supported Al2O3 ceramic membranes were used for MTBE/water separation by pervaporation. The NMR spectra revealed that MTMS evolves gradually from an oligomer to a highly cross-linked methyl-modified silica species. Methyl-modified silica species and pre-synthesized mesoporous silica microspheres combine into hydrophobic mesoporous MSL. MSL makes the α-Al2O3 ceramic membranes transfer from amphiphilic to hydrophobic and oleophilic. The MSL-supported α-Al2O3 ceramic membranes (MSL-10) exhibit an MTBE/water separation factor of 27.1 and a total flux of 0.448 kg m−2 h−1, which are considerably higher than those of previously reported membranes that are modified by other alkylsilanes via the post-grafting method. The mesopores within the MSL provide a pathway for the transport of MTBE molecules across the membranes. The presence of methyl groups on the external and inner surface is responsible for the favorable separation performance and the outstanding long-term stability of the MSL-supported porous α-Al2O3 ceramic membranes.

To improve the utilization of crop straws as a resource and the compatibility between straw fibers and cement-based materials, the hydration of modified straw fiber cement-based composite (SFCC) was studied. The structural characteristic of SFCC was investigated by FTIR, SEM, and XRD. The results show that the setting time of several modified straw fiber SFCC pastes was shorter than that of the unmodified straw fiber SFCC paste, and the best method of fiber modification to improve the setting time of the SFCC paste is Na2O·nSiO2 treatment. The recommended fiber modification method for improving the compatibility between straw fibers and cement-based materials is alkali modification, followed by pure acrylic emulsion modification and Na2O·nSiO2 modification. To improve the strength of SFCC, the straw fiber should be modified by alkali, followed by pure acrylic emulsion and Na2O·nSiO2 modification and the method of water modification is also recommended. The phase types and relative contents of crystalline hydration products mixed with the modified straw fiber SFCC are significantly higher than those of the unmodified fiber SFCC. The fiber treatment method that was most helpful to increase the structural density of hydrates of SFCC was alkali treatment and pure acrylic emulsion treatment, followed by Na2O·nSiO2 treatment.

This study aims to analyze the effect of high-altitude environment on drivers’ mental workload (MW), situation awareness (SA), and driving behaviour (DB), and to explore the relationship among those driving performances. Based on a survey, the data of 356 lowlanders engaging in driving activities at Tibetan Plateau (high-altitude group) and 341 lowlanders engaging in driving activities at low altitudes (low-altitude group) were compared and analyzed. The results suggest that the differences between the two groups are noteworthy. Mental workload of high-altitude group is significantly higher than that of low-altitude group, and their situation awareness is lower significantly. The possibility of risky driving behaviours for high-altitude group, especially aggressive violations, is higher. For the high-altitude group, the increase of mental workload can lead to an increase on aggressive violations, and the situation understanding plays a full mediating effect between mental workload and aggressive violations. Measures aiming at the improvement of situation awareness and the reduction of mental workload can effectively reduce the driving risk from high-altitude environment for lowlanders.

Biomass char is accepted as an environmentally friendly energy resource, and is promising for NO removal in industrial furnaces. NO reduction with biomass char (rice husk) was investigated in a fixed-bed quartz reactor. The influence of CO concentration, reaction temperature, initial NO concentration, and char loading on the NO reduction were evaluated. The results showed that the overall NO reduction reaction was dominated by the direct reaction of NO with char without CO. Increasing CO concentration resulted in an enhanced catalytic reaction between NO and CO over the char surface and a decreased carbon consumption of char. With decreasing temperature, the influence of CO concentration on NO reduction was strengthened. Over the test temperature range, char provided a surface to catalyze the NO–CO reaction at excess CO/NO ratio. Increasing the initial NO concentration led to an increasingly significant influence on NO reduction with the enhanced CO/NO ratio. With increased char loading, the enhancement of NO reduction became unobservable for excess CO/NO ratio. Reaction orders of NO and activation energy for NO reduction by char were 0.71 and 60.21 kJ·mol−1, respectively, against 0.82 and 34.60 kJ·mol−1, respectively, for NO reduction by CO, catalyzed by char.

Biochar materials are good reducers of nitrogen oxides. The composition and structure of biochar affect significantly its ability to reduce C−NO. In order to study the denitration of flue gases by biochar at high temperature, three kinds of biochar (bamboo charcoal (BC), rice husk ash (RHA), and straw charcoal (SC)) were mixed with cement raw meal in a fixed-bed quartz reactor at the temperature of 800−900 °C and O2 concentration of 0.5%−2%. The results showed that the initial denitration rate of BC was higher than that of RHA, and that of SC was the lowest. RHA had the largest specific surface area, and BC the smallest. The elements C, N, and O and the functional groups of the three types of biochar had a greater influence on the denitration rate than their structures. The denitration rate decreased faster as the O/C ratio increased, and the increase in the relative content of the N element induced the formation of nitrogen-containing functional groups catalyzing C−NO reduction. The content of the C−C bond affected directly the rate of denitration, and both (NCO)x and C−O bonds had a positive effect on the reduction capability of biochar. It can be concluded that the composition of biochar has an important effect on the reduction of C−NO.

The silica aerogels were prepared via a sol-gel technique and ambient pressure drying by using industrial solid wastes, dislodged sludges, as raw materials. A strategy was put forward to reduce the corrosion of equipment during the drying procedure. The pore structure, hydrophobicity, and thermal insulation property of the obtained samples were investigated in detail. The results show that the corrosion can be effectively avoided by using an equimolar mixture of trimethylchlorosilane (TMCS) and hexamethyldisilazane (HMDS) as silylation agents. At a Si:TMCS:HMDS molar ratio of 1:0.375:0.375, the silica aerogels possess a desirable pore structure with a pore volume of 3.3 ± 0.1 cm3/g and a most probable pore size of 18.5 nm, a high hydrophobicity with a water contact angle of 144.2 ± 1.1°, and a low thermal conductivity of 0.031 ± 0.001 W/(m∙K).