scholarly journals Preparation and characterization of masonry units, lightweight concrete based and agro-industrial wastes: a review

2013 ◽  
Vol 466 ◽  
pp. 012037
Author(s):  
C X Díaz-Fuentes
Cerâmica ◽  
2017 ◽  
Vol 63 (368) ◽  
pp. 530-535
Author(s):  
Z. L. M. Sampaio ◽  
A. E. Martinelli ◽  
T. S. Gomes

Abstract The recent increase in the construction industry has transformed concrete into an ideal choice to recycle a number of residues formerly discarded into the environment. Among various products, porcelain tile polishing, limestone and tire rubber residues are potential candidates to replace the fine aggregate of conventional mixtures. The aim of this study was to investigate the effect of the addition of varying contents of these residues in lightweight concrete where expanded clay replaced gravel. To that end, slump, compressive strength, density, void ratio, porosity and absorption tests were carried out. The densities of all concrete formulations studied were 10% lower to that of lightweight concrete (<1.850 kg/m³). Nevertheless, mixes containing 10 to 15% of combined residues reduced absorption, void ratio and porosity, at least 17% lower compared to conventional concrete. The strength of such formulations reached 27 MPa at 28 days with consistency of 9 to 12 cm, indicating adequate consistency and increased strength. In addition, the combination of low porosity, absorption and voids suggested improved durability.


2015 ◽  
Vol 69 (8) ◽  
Author(s):  
Alesandra Oriente ◽  
Robson Tramontina ◽  
Diandra de Andrades ◽  
Caroline Henn ◽  
Jose L. C. Silva ◽  
...  

AbstractProperties of beta-glucosidase produced by Aspergillus niger URM 6642 recently isolated from the Atlantic rainforest biome and its potential tolerance to saccharification of lignocellulosic biomass products and fermentation inhibitors was evaluated. The fungus was cultivated under solid state culture conditions at 37°C with different agro-industrial wastes. High levels of beta-glucosidase (3778.9 U g


2019 ◽  
Vol 11 (7) ◽  
pp. 1995 ◽  
Author(s):  
Sabrina Cajamarca ◽  
Douglas Martins ◽  
Juscimar da Silva ◽  
Mariana Fontenelle ◽  
Ítalo Guedes ◽  
...  

Several agro-industrial, livestock, and food wastes can be recycled to create biofertilizers. This diversity of raw materials can result in nutritional imbalance and an increase in heavy metal content, which could make the final product unfeasible. Thus, the chemical characterization of the raw materials and their influence on the sustainable and safe production of biofertilizers need to be better understood. In this context, the objective of the present study was to evaluate the chemical characteristics of agro-industrial residues used in the manufacture of an aerobic liquid biofertilizer. We analyzed the macronutrient, micronutrient, and trace metal contents of seven waste products used as raw materials to create a biofertilizer. In addition, a survey of secondary biofertilizer data from different residues was carried out that showed great heterogeneity in the chemical compositions of these residues, which has a direct impact on the agronomic efficiency of these biofertilizers. The characterization revealed that some materials may be contaminants of the soil, due to high levels of trace metals, especially cadmium. We conclude that the generation of detailed inventories, such as those of the nutrient and heavy metal contents of the raw materials and biofertilizers produced, is indispensable for the correct recommendation of biologically-based inputs in agriculture.


2018 ◽  
Vol 22 ◽  
pp. 154-159 ◽  
Author(s):  
Catalina Mihaela Helepciuc (Gradinaru) ◽  
Marinela Barbuta ◽  
Adrian Alexandru Serbanoiu
Keyword(s):  

Cerâmica ◽  
2018 ◽  
Vol 64 (371) ◽  
pp. 311-317 ◽  
Author(s):  
L. Simão ◽  
N. J. Lóh ◽  
D. Hotza ◽  
F. Raupp-Pereira ◽  
J. A. Labrincha ◽  
...  

Abstract Industrial wastes from pulp and paper mills are potentially useful materials to use as alternative materials in clinker production. In this study, eco-friendly clinkers were obtained using only waste as feedstock. Eco-friendly clinker with different C3S and C2S contents were produced and hydrated for 7 days at 40 °C, or for 28 and 90 days at room temperature. The potentialities of these waste and the products obtained were revealed through chemical (XRF), thermal (DTA/TG) and surface area (BET) analysis. For comparison, a common ordinary Portland cement (OPC) was tested. As expected, the hydration rate of formulations presenting higher C3S content was higher, generating higher amounts of Ca(OH)2. Furthermore, the amount of Portlandite formed was lower when compared to OPC.


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