Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : asphalt

Pretreatment of Sawdust for Producing Sawdust Concrete

Haitham H. Saeed

Engineering and Technology Journal, 2013, Volume 31, Issue 3, Pages 541-549

Sawdust concrete has some shortcomings due to the harmful effects of some organic soluble components existing in the sawdust which affects setting and strength of sawdust concrete. Also, volume changes of sawdust as an aggregate due to variation of moisture content, cause large volume changes in the sawdust concrete. In this work, sawdust was treated before using as an aggregate for making sawdust concrete. The treatment included boiling the sawdust in water containing hydrated lime in order to dissolve all soluble organic components. To reduce water absorption of sawdust, it was dried and treated with waterproofing material. Two types of waterproofing materials were used (cutback asphalt and classic varnish). The properties of sawdust concrete were highly improved using pretreated sawdust. The increase of compressive strength was up to 50% for moderate sawdust ratios. Flexural strength is also increased, water absorption and thermal conductivity were highly reduced, while the basic advantages of sawdust concrete such as lightness of weight, sawability and nailability were not affected.

Optimization of Asphalt Mix Improved by the Addition of Scrap Tires

Raghad O. Abass; Mohammed O. Abass; Falak O. Abass

Engineering and Technology Journal, 2009, Volume 27, Issue 12, Pages 2425-2446

The design of improved asphalt mix is achieved by the use of three major
variables , weight of scrap tires replaced by coarse base aggregate , particles size of scrap tires finally the weight of binder used (bitumen). The improved asphalt mix (IAM) requires a balance between rut
resistance and durability to resist cracking and moisture damage (stripping) .Accordingly several factors that influence rut resistance and durability are considered during the design process: The mix consisted of binder (3.0-6.5) %wt. , scrap tires (10-30) wt% with
particle size of (1-5) cm , is achieved by the application of box-Wilson design program. The improved mix is achieved by the use of both hot (wet) and cold (dry) processes for preparing the standard mix firstly under high temperature 168˚C with a continuous mixing for 2 hours then mould this hot mixture in standard molder found with the replacement of a coarse percent of aggregate by the different sizes of scrap tires (1-5)cm by the use of cold ( dry) technique , finally a
compression step is achieved with 52 hut for 20 min for both sides of molder in order to compress the prepared specimens then leaved for 24 hrs from the stability of specimens before any tests applied .
The results of selected variables are studied for prepared specimens to
check different important properties (mechanical, physical, chemical, thermomechanical and thermo-physical properties), then applied these result properties data in analytical computer programme software to check its fitting to design model selected and calculated the optimum properties and optimum variables for improved asphalt mix. After-ward the computerize analysis results shows that an optimum mix No.(11) reached high stability and flexibility, also gave excellent physical and
chemical properties as shown in present work below. Also described in this work the application and comparison between standard and improved optimum asphalt mix.