Suitability of sorghum stalk fibers for production of particleboard

Published Date
20 April 2015, Vol.120:15–21, doi:10.1016/j.carbpol.2014.12.001

Title 
Suitability of sorghum stalk fibers for production of particleboard

• Author 

• Abolghasem Khazaeian ^a
• Alireza Ashori ^b,,
• Mostafa Yahyavi Dizaj ^a

• aDepartment of Wood Engineering and Technology, Gorgan University of Agricultural Sciences and Natural Resources (GUASNR), Gorgan, Iran
• bDepartment of Chemical Technologies, Iranian Research Organization for Science and Technology (IROST), Tehran, Iran

Received 23 September 2014. Revised 27 November 2014. Accepted 2 December 2014. Available online 10 December 2014.

Highlights

• •
  The suitability of sorghum stalk as a raw material for particleboard manufacturing was studied.
• •
  Fractional factorial was used to find the optimum condition for the studied variable parameters.
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  SS has comparable fiber length with softwoods and fiber width values greater than hardwoods.
• •
  All of the particleboards produced from SS had IB higher than the EN standard requirement.
• •
  The presence of SS in the particleboards resulted in higher WA and TS values.

Abstract

The aim of this study was to investigate the suitability of sorghum (Sorghum bicolor) stalk (SS) as a promising raw material for particleboard manufacturing. The SS particles and industrial hardwood particles in various proportions were used as the raw materials for the surface and core layers of the three-layer particleboards. Commercial urea formaldehyde (UF) adhesive was used as a binder. Morphological and chemical characteristics of the SS were evaluated. Effects of five variable parameters on the physical (thickness swelling (TS), water absorption (WA)), and mechanical (modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB)) properties of the particleboards were determined. Other parameters such as type of resin (UF), hardener content (1%), type of hardener (NH₄Cl), press closing time (5 mm/s), board density (0.70 g/cm³), and press pressure (30 kg/m²) were held constant. Fractional factorial was used to find the optimum condition for the studied variable parameters. The morphological results showed that SS had comparable fiber length with softwoods and fiber width and wall thickness values greater than the hardwood of common forest species. They had higher hot-water solubility values, lignin and ash contents than those of the other woody materials. The experimental results showed that increasing of SS particles usage in the surface layer significantly affects the board properties. Containing 50 wt% SS particles in the surface, the MOE and MOR values exceed the minimum requirements of the European norms (EN) standards, for general purposes. All of the particleboards produced from SS had IB higher than the EN standard requirement. The presence of SS in the particleboards resulted in higher WA and TS values. All the mechanical properties of the boards decreased when the press temperature was increased from 160 to 180 °C. Finally, it can be stated that SS has enough potential as a supplement fibrous material, in combination with industrial hardwood particles, for particleboard manufacturing and indoor applications.

Keywords

• Sorghum
• Particleboard
• Resin content
• Physical properties
• Mechanical properties

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• ⁎ 
  Corresponding author. Tel.: +98 21 56275192; fax: +98 21 56275191.

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http://www.sciencedirect.com/science/article/pii/S0144861714011758

Effects of copper slag and recycled concrete aggregate on the properties of CIR mixes with bitumen emulsion, rice husk ash, Portland cement and fly ash

Published Date
15 October 2015, Vol.96:172–180, doi:10.1016/j.conbuildmat.2015.08.021

Title 
Effects of copper slag and recycled concrete aggregate on the properties of CIR mixes with bitumen emulsion, rice husk ash, Portland cement and fly ash

• Author 

• Ali Behnood ^a,,
• Mahsa Modiri Gharehveran ^a,
• Farhad Gozali Asl ^b,
• Mahmoud Ameri ^b,

• aLyles School of Civil Engineering, Purdue University, 550 Stadium Mall Dr., West Lafayette, IN 47907-2051, USA
• bSchool of Civil Engineering, Iran University of Science and Technology, P.O. Box 16489, Narmak, Tehran, Iran

Received 1 April 2015. Revised 21 July 2015. Accepted 5 August 2015. Available online 9 August 2015.

Highlights

• •
  The feasibility of the use of copper slag and recycled concrete aggregate as substitutes for virgin aggregates in CIR mixes was investigated.
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  Effects of different additives such as Portland cement, FA, and RHA were studied.
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  Copper slag and different additives improved the durability and mechanical properties of CIR mixes.
• •
  Recycled concrete aggregate was found to be acceptable type of aggregate as a substitute for virgin aggregate in CIR mixtures.
• •
  Hazardous environmental effects were not observed.

Abstract

Construction and maintenance of roads require a large volume of aggregates for use in base, sub-base and surface layers. At the same time, the expansion of asphalt roadways results in the production of a large amount of asphalt road waste, known as reclaimed asphalt pavement (RAP). This paper aims to investigate the feasibility of the use of copper slag and recycled concrete aggregate (RCA) as substitutes for virgin aggregates in modifying the gradation of cold recycled mixes made with RAP material. In addition, the effects of three types of additives including Portland cement, fly ash, and rice husk ash on the properties of recycled mixtures were investigated. Marshall, Indirect tensile strength, resilient modulus, moisture susceptibility, and dynamic creep tests were conducted to evaluate the mechanical properties of the mixes. Toxicity characteristic leaching procedure was used to assess the environmental impacts of copper slag. The use of copper slag had better results than limestone and RCA probably due to better interlocking and superior physical and mechanical properties. With regard to the effects of additives, Portland cement was found to be the most effective additive. The difference between fly ash and rice husk ash was found to be statistically insignificant.

Keywords

• Cold in place recycling
• Copper slag
• Recycled concrete aggregate
• Rice husk ash
• Fly ash
• Asphalt emulsion.

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• ⁎ 
  Corresponding author.

For further details log on website :

http://www.sciencedirect.com/science/article/pii/S0950061815302373

Experimental investigation on mineral and organic fibers effect on resilient modulus and dynamic creep of stone matrix asphalt and continuous graded mixtures in three temperature levels

Published Date
1 October 2015, Vol.95:232–242, doi:10.1016/j.conbuildmat.2015.07.146

Title 
Experimental investigation on mineral and organic fibers effect on resilient modulus and dynamic creep of stone matrix asphalt and continuous graded mixtures in three temperature levels

• Author 

• Mohammad Lavasani ^a,,
• Manouchehr Latifi Namin ^b,
• Homa Fartash ^a,

• aCivil and Environmental Engineering, Florida International University, 10555 W Flagler St, EC3715, Miami, FL 33174, USA
• bSchool of Civil Engineering, College of Engineering, University of Tehran, Enghelab Ave., Tehran, Iran

Received 16 January 2015. Revised 17 June 2015. Accepted 14 July 2015. Available online 20 July 2015.

Highlights

• •
  This study considered effects of two fibers on SMA and HMA mixtures properties.
• •
  HMA mixtures showed significantly higher resilient modulus than SMA.
• •
  Rutting potential of HMA mixtures was lower than SMA.
• •
  In higher temperatures more fiber content is required to improve properties.

Abstract

Two fiber types were used in this study to evaluate resilient modulus and dynamic creep behavior of stone matrix asphalt and continuous graded hot mixed asphalt versus various fiber contents in three levels of temperature. Generally, continuous graded mixtures presented better mechanical properties in both resilient modulus and dynamic creep tests. Fibers have shown great effect not only on asphalt drain-down, but on mechanical properties of samples. Considering the temperature effect, the higher the temperature is, the higher fiber content is required to improve mechanical characteristics of asphalt concrete.

Keywords

• HMA
• SMA
• Resilient modulus
• Dynamic creep
• Fiber
• Linear discriminant analysis.

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• ⁎ 
  Corresponding author.

For further details log on website :

http://www.sciencedirect.com/science/article/pii/S0950061815301471