scholarly journals Physicomechanical and Antimicrobial Characteristics of Cement Composites with Selected Nano-Sized Oxides and Binary Oxide Systems

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 661
Author(s):  
Patryk Jędrzejczak ◽  
Łukasz Ławniczak ◽  
Agnieszka Ślosarczyk ◽  
Łukasz Klapiszewski

In recent years, increasing attention has been paid to the durability of building materials, including those based on cementitious binders. Important aspects of durability include the increase of the strength of the cement matrix and enhancement of material resistance to external factors. The use of nanoadditives may be a way to meet these expectations. In the present study, zinc, titanium and copper oxides, used in single and binary systems (to better the effect of their performance), were applied as additives in cement mortars. In the first part of this work, an extensive physicochemical analysis of oxides was carried out, and in the second, their application ranges in cement mortars were determined. The subsequent analyses were employed in determining the physicochemical properties of pristine oxides: Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray fluorescence (EDXRF), scanning electron microscopy (SEM), measurement of the particle size distribution, as well as zeta potential measurement depending on the pH values. Influence on selected physicomechanical parameters of the cement matrix and resistance to the action of selected Gram-positive and Gram-negative bacteria and fungi were also examined. Our work indicated that all nanoadditives worsened the mechanical parameters of mortars during the first 3 days of hardening, while after 28 days, an improvement was achieved for zinc and titanium(IV) oxides. Binary systems and copper(II) oxide deteriorated in strength parameters throughout the test period. In contrast, copper(II) oxide showed the best antibacterial activity among all the tested oxide systems. Based on the inhibitory effect of the studied compounds, the following order of microbial susceptibility to inhibition of growth on cement mortars was established (from the most susceptible, to the most resistant): E. coli < S. aureus < C. albicans < B. cereus = P. aeruginosa < P. putida.

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3756 ◽  
Author(s):  
Magdalena Janus ◽  
Szymon Mądraszewski ◽  
Kamila Zając ◽  
Ewelina Kusiak-Nejman ◽  
Antoni W. Morawski ◽  
...  

In this paper, studies of the mechanical properties and photocatalytic activity of new photoactive cement mortars are presented. The new building materials were obtained by the addition of 1, 3, and 5 wt % (based on the cement content) of nitrogen-modified titanium dioxide (TiO2/N) to the cement matrix. Photocatalytic active cement mortars were characterized by measuring the flexural and the compressive strength, the hydration heat, the zeta potential of the fresh state, and the initial and final setting time. Their photocatalytic activity was tested during NOx decomposition. The studies showed that TiO2/N gives the photoactivity of cement mortars during air purification with an additional positive effect on the mechanical properties of the hardened mortars. The addition of TiO2/N into the cement shortened the initial and final setting time, which was distinctly observed using 5 wt % of the photocatalyst in the cement matrix.


2020 ◽  
Vol 23 (2) ◽  
pp. 67-72
Author(s):  
Banjo Akinyemi ◽  
Temidayo E. Omoniyi ◽  
Olugbenga Elemile ◽  
Oluwafemi Arowofila

AbstractThe study considers the use of rice chaffs (husks) as an aggregate in a composite cement matrix system. Cement mortars were modified using styrene butadiene rubber polymer for strengthening. The goal is to develop a lightweight building material with good thermal insulation properties out of agricultural waste. The compressive strength, split tensile strength and flexural strength were experimentally evaluated. Further analyses of the samples were carried out by means of scanning electron microscope and energy dispersive spectroscopy. The key results obtained were presented and analysed with the performance of the proposed husk-crete building material showing adequate properties essential for a lightweight structural material with possible applications for non-structural purposes.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3079
Author(s):  
Beata Jaworska ◽  
Dominika Stańczak ◽  
Joanna Tarańska ◽  
Jerzy Jaworski

The generation of energy for the needs of the population is currently a problem. In consideration of that, the biomass combustion process has started to be implemented as a new source of energy. The dynamic increase in the use of biomass for energy generation also resulted in the formation of waste in the form of fly ash. This paper presents an efficient way to manage this troublesome material in the polymer–cement composites (PCC), which have investigated to a lesser extent. The research outlined in this article consists of the characterization of biomass fly ash (BFA) as well as PCC containing this waste. The characteristics of PCC with BFA after 3, 7, 14, and 28 days of curing were analyzed. Our main findings are that biomass fly ash is suitable as a mineral additive in polymer–cement composites. The most interesting result is that the addition of biomass fly ash did not affect the rheological properties of the polymer–cement mortars, but it especially influenced its compressive strength. Most importantly, our findings can help prevent this byproduct from being placed in landfills, prevent the mining of new raw materials, and promote the manufacture of durable building materials.


2021 ◽  
Vol 193 ◽  
pp. 110594
Author(s):  
Hanbo Chen ◽  
Peng Qin ◽  
Xing Yang ◽  
Amit Bhatnagar ◽  
Sabry M. Shaheen ◽  
...  

Author(s):  
PAULA ALEJANDRA GIRALDO VILLAMIL ◽  
ANDRÉS CAMILO ANDRADE BURBANO ◽  
LUIS POMBO OSPINA ◽  
JANETH ARIAS PALACIOS ◽  
ÓSCAR EDUARDO RODRÍGUEZ AGUIRRE

Objective: The objective of the study was to determine the antimicrobial activity of leaf and flower extract in Chromolaena scabra (L. f.) R.M. King and H. Rob., against selected strains of bacteria and fungi. Methods: The agar diffusion method with plate perforation was developed; the microorganisms used were strains of Staphylococcus aureus and Escherichia coli, Aspergillus niger, and Penicillium digitatum. Rifampicin was used as a positive control. The evaluation was performed by measuring the diameter of the growth inhibition zones around the holes. The inhibitory effect of the plant extracts was obtained by its efficiency compared to the positive control. A comparison with fluconazole and ketoconazole was performed to determine how much of the extract is required to cause inhibition of fungal growth from the standard. Results: IC50 was determined by relating the ln of mass evaluated with respect to the square of the inhibition halo; ethanolic extracts of leaves and flowers of petroleum ether with IC50 values of 85.8 mg/ml and 50.3 mg/ml showed the highest inhibitory effect against S. aureus; the extract of petroleum ether and ethanol from leaves with IC50 of 64 mg/ml and 60 mg/ml, respectively. They were effective with A. niger. Leaf petroleum ether extract showed the best relative antifungal activity against A. niger with respect to fluconazole equivalent to 459.51 when fluconazole is 1.0. Conclusion: The extracts with high potential to inhibit the growth of microorganisms were determined to be ether flowers of petroleum and ethanol leaf extracts.


2019 ◽  
Vol 296 ◽  
pp. 3-8
Author(s):  
David Bujdoš ◽  
Lucia Bulíková

Nowadays, the colouring is used in wide range of architectural concrete. Therefore, determination efficiency of pigments in case of particular combination of input materials is necessary. The research deals with influence of concentration of liquid inorganic pigments on the resulting colour of cement mortars. Two liquid pigments (yellow, red) were used for measurement purposes to verify their optimal ratio to achieve the best colouring of cement specimens. Pigments were mixed in the mortars of two types of cements used for architectural and decorative design. The colour change was determined using Konica Minolta spectrophotometer in colour space CIE Lab (1976). General definition of deviation in the colour space ΔELab was applied for calculating of colour deviation. From the results of the laboratory tests is obvious that significant change of the colour of cement specimens do not show between the concentration of 6% and 9% of the pigment per cement weight yet. Consequently, using of high ratio of pigment than 9% is not profitable neither for purchaser, nor builder. Future research will focus on trials with a more elaborate share of pigment and it will have importance for price optimization in the construction industry.


2018 ◽  
Vol 34 (4) ◽  
pp. 2043-2050 ◽  
Author(s):  
Buhani Buhani ◽  
Megafhit Puspitarini ◽  
Rahmawaty Rahmawaty ◽  
Suharso Suharso ◽  
Mita Rilyanti ◽  
...  

In this research, it has been performed carbon activation of oil palm shells (CAC) prepared by chemical treatment as adsorbents of phenol and methylene blue (MB) in solution either in the form of single or in pair solution. The activation of carbon from the oil palm shells was done physically at a temperature of 700°C for 1 hour continued with chemical activation using 10% H3PO4 for 24 hours. Identification of functional groups on the carbon from oil palm shell before and after chemically activated was performed using infrared spectrophotometer (IR) and analysis of its surface morphology was carried out using scanning electron microscope (SEM). The phenol and MB adsorption process was performed in single and binary systems using the batch method. The adsorption of phenol on CAC is optimum at pH 8 while MB at pH 11 with optimum contact time of 90 min for phenol and 120 min for MB respectively. The phenol and MB adsorption data on the CAC in the single system follow the pseudo-second-order kinetics model with the adsorption rate constant of 0.399 and 0.769 g mmol-1 min-1 respectively. The adsorption isotherms of phenol and MB in CAC tend to follow Freundlich adsorption isotherm pattern with the adsorption intensity factor (n) for phenol, MB, phenol/MB, and MB/phenol: 1.739, 1.341, 1.334, and 1.293 respectively. The adsorbent of CAC is effective to remove phenol and MB in solution, either in single or paired condition.


2020 ◽  
pp. 114586
Author(s):  
Lorena Delgadillo-Velasco ◽  
Virginia Hernández-Montoya ◽  
Luis A. Ramírez-Montoya ◽  
Miguel A. Montes-Morán ◽  
Ma. del Rosario Moreno-Virgen ◽  
...  

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