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Mohammad Shekarchi - One of the best experts on this subject based on the ideXlab platform.
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in situ study of chloride ingress in concretes containing Natural Zeolite metakaolin and silica fume exposed to various exposure conditions in a harsh marine environment
Construction and Building Materials, 2013Co-Authors: Mahdi Valipour, Mohammad Shekarchi, Farhad Pargar, Sara Khani, Masoud MoradianAbstract:The Persian Gulf is well known as one of the most aggressive environments in the world because of its high relative humidity, temperature and concentration of chloride ions. Therefore, studying the deterioration processes, such as the chloride ion penetration process, that lead to severe reinforcement corrosion in aggressive environments is necessary. To improve the durability and serviceability of concrete structures in such environments, several investigations have been conducted that address the addition of silica fume and metakaolin, while less attention has been given to the newly introduced pozzolan called Natural Zeolite. In this paper, the performance of concretes containing Natural Zeolite, metakaolin and silica fume and that of concretes with different water-to-binder ratios under various exposure conditions in terms of chloride ion diffusivity were investigated. To achieve this objective, concrete specimens with water-to-binder ratios (w/b) of 0.35, 0.40, 0.45 and 0.50 were fabricated. In addition, to examine the performance of three different pozzolans, other specimens with constant water-to-binder ratios of 0.40 containing 10% Natural Zeolite, 5% metakaolin and 5% silica fume were prepared. All of the specimens were subjected to four exposure conditions (tidal, splash, atmosphere and soil). The results were obtained from a field exposure site and indicate that Natural Zeolite exhibits good performance in terms of improving the durability of concrete in harsh environments. In addition, it is concluded that splash zones affect concrete structures more harshly than tidal zones.
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mechanical and durability properties of self consolidating high performance concrete incorporating Natural Zeolite silica fume and fly ash
Construction and Building Materials, 2013Co-Authors: Fereshteh A Sabet, Nicolas Ali Libre, Mohammad ShekarchiAbstract:Abstract Mineral admixtures are widely used as cement replacement materials in both high performance concrete (HPC) and self consolidating concrete (SCC). While the effect of mineral admixtures on rheological properties of SCC and mechanical behavior of HPC has been investigated by many researchers, further research is needed to optimize the effective dosage of these admixtures in self consolidating high performance concrete (SCHPC). Moreover, the effects of some mineral admixtures such as Natural Zeolite on properties of SCHPC has not been well established yet. This paper discusses the effect of Natural Zeolite, silica fume and fly ash on the properties of fresh and hardened concrete. Slump flow, superplasticizer demand, compressive strength, electrical resistivity, water absorption and chloride permeability were measured for all mixes. The test results indicate that incorporation of mineral admixtures generally improve mechanical and durability characteristics of the mixes. However, silica fume is slightly more effective than Natural Zeolite or fly ash in improving durability properties of SCHPCs, while Natural Zeolite is much more cost effective.
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use of Natural Zeolite as a supplementary cementitious material
Cement & Concrete Composites, 2010Co-Authors: Babak Ahmadi, Mohammad ShekarchiAbstract:Natural Zeolite, a type of frame-structured hydrated aluminosilicate mineral, is used abundantly as a type of Natural pozzolanic material in some regions of the world. In this work, the effectiveness of a locally quarried Zeolite in enhancing mechanical and durability properties of concrete is evaluated and is also compared with other pozzolanic admixtures. The experimental tests included three parts: In the first part, the pozzolanic reactivity of Natural Zeolite and silica fume were examined by a thermogravimetric method. In this case, the results indicated that Natural Zeolite was not as reactive as silica fume but it showed a good pozzolanic reactivity. In the second part, Zeolite and silica fume were substituted for cement in different proportions in concrete mixtures, and several physical and durability tests of concrete were performed. These experimental tests included slump, compressive strength, water absorption, oxygen permeability, chloride diffusion, and electrical resistivity of concrete. Based on these results, the performance of concretes containing different contents of Zeolite improved and even were comparable to or better than that of concretes prepared with silica fume replacements in some cases. Finally, a comparative study on effect of Zeolite and fly ash on limiting ASR expansion of mortar was performed according to ASTM C 1260 and ASTM C 1567. Expansion tests on mortar prisms showed that Zeolite is as effective as fly ash to prevent deleterious expansion due to ASR.
Yuansong Wei - One of the best experts on this subject based on the ideXlab platform.
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impacts of zero valent iron Natural Zeolite and dnase on the fate of antibiotic resistance genes during thermophilic and mesophilic anaerobic digestion of swine manure
Bioresource Technology, 2018Co-Authors: Junya Zhang, Qianwen Sui, Hui Zhong, Xiaoshan Meng, Ziyue Wang, Yawei Wang, Yuansong WeiAbstract:This study investigated the fate of antibiotic resistance genes (ARGs) during mesophilic (mAD) and thermophilic digestion (tAD) of swine manure through zero valent iron (ZVI), Natural Zeolite and Dnase addition. Changes of microbial community, intI1, heavy metal resistance genes (MRGs) and virulence factors (VFs) were followed to clarify the influencing factors to ARGs reduction. Results showed that AD could realize ARGs reduction with tAD superior to mAD, and ZVI and Natural Zeolite could further enhance the reduction, especially for Natural Zeolite addition at mAD. The reduction efficiency of the relative abundance of ARGs was increased by 33.3% and 138.5% after ZVI and Natural Zeolite addition, respectively, but Dnase deteriorated ARGs reduction at mAD. Most of ARGs could be reduced effectively except sulII and tetM. Network analysis and partial redundancy analysis indicated that co-occurrence of MRGs followed by microbial community contributed the most to the variation of ARGs fate among treatments.
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impacts of addition of Natural Zeolite or a nitrification inhibitor on antibiotic resistance genes during sludge composting
Water Research, 2016Co-Authors: Junya Zhang, Qianwen Sui, Meixue Chen, Juan Tong, Chao Jiang, Yuxiu Zhang, Yuansong WeiAbstract:Composting is commonly used for the treatment and resource utilization of sewage sludge, and Natural Zeolite and nitrification inhibitors can be used for nitrogen conservation during sludge composting, while their impacts on ARGs control are still unclear. Therefore, three lab-scale composting reactors, A (the control), B (Natural Zeolite addition) and C (nitrification inhibitor addition of 3,4-dimethylpyrazole phosphate, DMPP), were established. The impacts of Natural Zeolite and DMPP on the levels of ARGs were investigated, as were the roles that heavy metals, mobile genetic elements (MGEs) and the bacterial community play in ARGs evolution. The results showed that total ARGs copies were enriched 2.04 and 1.95 times in reactors A and C, respectively, but were reduced by 1.5% in reactor B due to the reduction of conjugation and co-selection of heavy metals caused by Natural Zeolite. Although some ARGs (blaCTX-M, blaTEM, ermB, ereA and tetW) were reduced by 0.3-2 logs, others (ermF, sulI, sulII, tetG, tetX, mefA and aac(6')-Ib-cr) increased by 0.3-1.3 logs after sludge composting. Although the contributors for the ARGs profiles in different stages were quite different, the results of a partial redundancy analysis, Mantel test and Procrustes analysis showed that the bacterial community was the main contributor to the changes in ARGs compared to MGEs and heavy metals. Network analysis determined the potential host bacteria for various ARGs and further confirmed our results.
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influence of Natural Zeolite and nitrification inhibitor on organics degradation and nitrogen transformation during sludge composting
Environmental Science and Pollution Research, 2016Co-Authors: Junya Zhang, Qianwen Sui, Meixue Chen, Juan Tong, Yuansong WeiAbstract:Sludge composting is one of the most widely used treatments for sewage sludge resource utilization. Natural Zeolite and nitrification inhibitor (NI) are widely used during composting and land application for nitrogen conservation, respectively. Three composting reactors (A--the control, B--Natural Zeolite addition, and C--3,4-dimethylpyrazole phosphate (DMPP) addition) were established to investigate the influence of NI and Natural Zeolite addition on organics degradation and nitrogen transformation during sludge composting conducted at the lab scale. The results showed that, in comparison with the control, Natural Zeolite addition accelerated organics degradation and the maturity of sludge compost was higher, while the DMPP addition slowed down the degradation of organic matters. Meanwhile, the nitrogen transformation functional genes including those responses for nitrification (amoA and nxrA) and denitrification (narG, nirS, nirK, and nosZ) were quantified through quantitative PCR (qPCR) to investigate the effects of Natural Zeolites and DMPP addition on nitrogen transformation. Although no significant difference in the abundance of nitrogen transformation functional genes was observed between treatments, addition of both Natural Zeolite and DMPP increases the final total nitrogen content by 48.6% and 23.1%, respectively. The ability of Natural Zeolite for nitrogen conservation was due to the absorption of NH3 by compost, and nitrogen conservation by DMPP was achieved by the source reduction of denitrification. Besides, it was assumed that the addition of Natural Zeolite and DMPP may affect the activity of these genes instead of the abundance.
Junya Zhang - One of the best experts on this subject based on the ideXlab platform.
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impacts of zero valent iron Natural Zeolite and dnase on the fate of antibiotic resistance genes during thermophilic and mesophilic anaerobic digestion of swine manure
Bioresource Technology, 2018Co-Authors: Junya Zhang, Qianwen Sui, Hui Zhong, Xiaoshan Meng, Ziyue Wang, Yawei Wang, Yuansong WeiAbstract:This study investigated the fate of antibiotic resistance genes (ARGs) during mesophilic (mAD) and thermophilic digestion (tAD) of swine manure through zero valent iron (ZVI), Natural Zeolite and Dnase addition. Changes of microbial community, intI1, heavy metal resistance genes (MRGs) and virulence factors (VFs) were followed to clarify the influencing factors to ARGs reduction. Results showed that AD could realize ARGs reduction with tAD superior to mAD, and ZVI and Natural Zeolite could further enhance the reduction, especially for Natural Zeolite addition at mAD. The reduction efficiency of the relative abundance of ARGs was increased by 33.3% and 138.5% after ZVI and Natural Zeolite addition, respectively, but Dnase deteriorated ARGs reduction at mAD. Most of ARGs could be reduced effectively except sulII and tetM. Network analysis and partial redundancy analysis indicated that co-occurrence of MRGs followed by microbial community contributed the most to the variation of ARGs fate among treatments.
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impacts of addition of Natural Zeolite or a nitrification inhibitor on antibiotic resistance genes during sludge composting
Water Research, 2016Co-Authors: Junya Zhang, Qianwen Sui, Meixue Chen, Juan Tong, Chao Jiang, Yuxiu Zhang, Yuansong WeiAbstract:Composting is commonly used for the treatment and resource utilization of sewage sludge, and Natural Zeolite and nitrification inhibitors can be used for nitrogen conservation during sludge composting, while their impacts on ARGs control are still unclear. Therefore, three lab-scale composting reactors, A (the control), B (Natural Zeolite addition) and C (nitrification inhibitor addition of 3,4-dimethylpyrazole phosphate, DMPP), were established. The impacts of Natural Zeolite and DMPP on the levels of ARGs were investigated, as were the roles that heavy metals, mobile genetic elements (MGEs) and the bacterial community play in ARGs evolution. The results showed that total ARGs copies were enriched 2.04 and 1.95 times in reactors A and C, respectively, but were reduced by 1.5% in reactor B due to the reduction of conjugation and co-selection of heavy metals caused by Natural Zeolite. Although some ARGs (blaCTX-M, blaTEM, ermB, ereA and tetW) were reduced by 0.3-2 logs, others (ermF, sulI, sulII, tetG, tetX, mefA and aac(6')-Ib-cr) increased by 0.3-1.3 logs after sludge composting. Although the contributors for the ARGs profiles in different stages were quite different, the results of a partial redundancy analysis, Mantel test and Procrustes analysis showed that the bacterial community was the main contributor to the changes in ARGs compared to MGEs and heavy metals. Network analysis determined the potential host bacteria for various ARGs and further confirmed our results.
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influence of Natural Zeolite and nitrification inhibitor on organics degradation and nitrogen transformation during sludge composting
Environmental Science and Pollution Research, 2016Co-Authors: Junya Zhang, Qianwen Sui, Meixue Chen, Juan Tong, Yuansong WeiAbstract:Sludge composting is one of the most widely used treatments for sewage sludge resource utilization. Natural Zeolite and nitrification inhibitor (NI) are widely used during composting and land application for nitrogen conservation, respectively. Three composting reactors (A--the control, B--Natural Zeolite addition, and C--3,4-dimethylpyrazole phosphate (DMPP) addition) were established to investigate the influence of NI and Natural Zeolite addition on organics degradation and nitrogen transformation during sludge composting conducted at the lab scale. The results showed that, in comparison with the control, Natural Zeolite addition accelerated organics degradation and the maturity of sludge compost was higher, while the DMPP addition slowed down the degradation of organic matters. Meanwhile, the nitrogen transformation functional genes including those responses for nitrification (amoA and nxrA) and denitrification (narG, nirS, nirK, and nosZ) were quantified through quantitative PCR (qPCR) to investigate the effects of Natural Zeolites and DMPP addition on nitrogen transformation. Although no significant difference in the abundance of nitrogen transformation functional genes was observed between treatments, addition of both Natural Zeolite and DMPP increases the final total nitrogen content by 48.6% and 23.1%, respectively. The ability of Natural Zeolite for nitrogen conservation was due to the absorption of NH3 by compost, and nitrogen conservation by DMPP was achieved by the source reduction of denitrification. Besides, it was assumed that the addition of Natural Zeolite and DMPP may affect the activity of these genes instead of the abundance.
Qianwen Sui - One of the best experts on this subject based on the ideXlab platform.
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impacts of zero valent iron Natural Zeolite and dnase on the fate of antibiotic resistance genes during thermophilic and mesophilic anaerobic digestion of swine manure
Bioresource Technology, 2018Co-Authors: Junya Zhang, Qianwen Sui, Hui Zhong, Xiaoshan Meng, Ziyue Wang, Yawei Wang, Yuansong WeiAbstract:This study investigated the fate of antibiotic resistance genes (ARGs) during mesophilic (mAD) and thermophilic digestion (tAD) of swine manure through zero valent iron (ZVI), Natural Zeolite and Dnase addition. Changes of microbial community, intI1, heavy metal resistance genes (MRGs) and virulence factors (VFs) were followed to clarify the influencing factors to ARGs reduction. Results showed that AD could realize ARGs reduction with tAD superior to mAD, and ZVI and Natural Zeolite could further enhance the reduction, especially for Natural Zeolite addition at mAD. The reduction efficiency of the relative abundance of ARGs was increased by 33.3% and 138.5% after ZVI and Natural Zeolite addition, respectively, but Dnase deteriorated ARGs reduction at mAD. Most of ARGs could be reduced effectively except sulII and tetM. Network analysis and partial redundancy analysis indicated that co-occurrence of MRGs followed by microbial community contributed the most to the variation of ARGs fate among treatments.
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impacts of addition of Natural Zeolite or a nitrification inhibitor on antibiotic resistance genes during sludge composting
Water Research, 2016Co-Authors: Junya Zhang, Qianwen Sui, Meixue Chen, Juan Tong, Chao Jiang, Yuxiu Zhang, Yuansong WeiAbstract:Composting is commonly used for the treatment and resource utilization of sewage sludge, and Natural Zeolite and nitrification inhibitors can be used for nitrogen conservation during sludge composting, while their impacts on ARGs control are still unclear. Therefore, three lab-scale composting reactors, A (the control), B (Natural Zeolite addition) and C (nitrification inhibitor addition of 3,4-dimethylpyrazole phosphate, DMPP), were established. The impacts of Natural Zeolite and DMPP on the levels of ARGs were investigated, as were the roles that heavy metals, mobile genetic elements (MGEs) and the bacterial community play in ARGs evolution. The results showed that total ARGs copies were enriched 2.04 and 1.95 times in reactors A and C, respectively, but were reduced by 1.5% in reactor B due to the reduction of conjugation and co-selection of heavy metals caused by Natural Zeolite. Although some ARGs (blaCTX-M, blaTEM, ermB, ereA and tetW) were reduced by 0.3-2 logs, others (ermF, sulI, sulII, tetG, tetX, mefA and aac(6')-Ib-cr) increased by 0.3-1.3 logs after sludge composting. Although the contributors for the ARGs profiles in different stages were quite different, the results of a partial redundancy analysis, Mantel test and Procrustes analysis showed that the bacterial community was the main contributor to the changes in ARGs compared to MGEs and heavy metals. Network analysis determined the potential host bacteria for various ARGs and further confirmed our results.
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influence of Natural Zeolite and nitrification inhibitor on organics degradation and nitrogen transformation during sludge composting
Environmental Science and Pollution Research, 2016Co-Authors: Junya Zhang, Qianwen Sui, Meixue Chen, Juan Tong, Yuansong WeiAbstract:Sludge composting is one of the most widely used treatments for sewage sludge resource utilization. Natural Zeolite and nitrification inhibitor (NI) are widely used during composting and land application for nitrogen conservation, respectively. Three composting reactors (A--the control, B--Natural Zeolite addition, and C--3,4-dimethylpyrazole phosphate (DMPP) addition) were established to investigate the influence of NI and Natural Zeolite addition on organics degradation and nitrogen transformation during sludge composting conducted at the lab scale. The results showed that, in comparison with the control, Natural Zeolite addition accelerated organics degradation and the maturity of sludge compost was higher, while the DMPP addition slowed down the degradation of organic matters. Meanwhile, the nitrogen transformation functional genes including those responses for nitrification (amoA and nxrA) and denitrification (narG, nirS, nirK, and nosZ) were quantified through quantitative PCR (qPCR) to investigate the effects of Natural Zeolites and DMPP addition on nitrogen transformation. Although no significant difference in the abundance of nitrogen transformation functional genes was observed between treatments, addition of both Natural Zeolite and DMPP increases the final total nitrogen content by 48.6% and 23.1%, respectively. The ability of Natural Zeolite for nitrogen conservation was due to the absorption of NH3 by compost, and nitrogen conservation by DMPP was achieved by the source reduction of denitrification. Besides, it was assumed that the addition of Natural Zeolite and DMPP may affect the activity of these genes instead of the abundance.
Robert Cerný - One of the best experts on this subject based on the ideXlab platform.
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engineering properties of concrete containing Natural Zeolite as supplementary cementitious material strength toughness durability and hygrothermal performance
Cement & Concrete Composites, 2015Co-Authors: Eva Vejmelkova, Tereza Kulovaná, Martin Keppert, Dana Koňakova, Jaromir žumar, Pavla Rovnanikova, Zbyněk Kersner, Martin Sedlmajer, Robert CernýAbstract:Abstract A complex analysis of engineering properties of concrete containing Natural Zeolite as supplementary cementitious material in the blended Portland-cement based binder in an amount of up to 60% by mass is presented. The studied parameters include basic physical characteristics, mechanical and fracture–mechanics properties, durability characteristics, and hygric and thermal properties. Experimental results show that 20% Zeolite content in the blended binder is the most suitable option. For this cement replacement level the compressive strength, bending strength, effective fracture toughness, effective toughness, and specific fracture energy are only slightly worse than for the reference Portland-cement concrete. The frost resistance, de-icing salt resistance, and chemical resistance to MgCl2, NH4Cl, Na2SO4, and HCl are improved. The hygrothermal performance of hardened mixes containing 20% Natural Zeolite, as assessed using the measured values of water absorption coefficient, water vapor diffusion coefficient, water vapor sorption isotherms, thermal conductivity, and specific heat capacity, is satisfactory.
