The Ground Penetrating Radar (GPR) is frequently used in pavement engineering
for road pavement inspection. The main objective of this work is to validate
nondestructive, quick and powerful measurements using GPR for assessment of subgrade
and asphalt /concrete conditions. In the present study, two different antennas
(250, 500 MHz) were used. The case studies are presented was carried in University
of Baghdad over about 100m of paved road. After data acquisition and radar grams
collection, they have been processed using RadExplorer V1.4 software
implementing different filters with the most effective ones (time zero adjustment and
DC removal) in addition to other interpretation tool parameters.
The interpretation results showed that with 250 MHz antenna, the buried plastic pipe
and the flexible pavement layer were identified. The later appeared as one layer
without identifying the rigid pavement layer. With 500 MHz antenna, the plastic
pipe, rigid pavement, appeared clearly. Moreover, the short type of maximum time
window using antenna 500 MHz appeared to be the most suitable for detecting some
radar anomalies (plastic pipe, and pavement thickness) which were clearly defined.
While, the suitable radar wave velocity was 100 m/ns for estimation of the flexible
and rigid pavement layer thicknesses respectively. No change is obtained with
changing point interval. . Finally, this diagnostic tool of GPR for pavement defects
and damages investigations seems very promising, cost effective and efficient in its
implementation.
This research investigated the effect of adding two groups of reinforcement materials, including bioactive materials Hydroxyapatite (HA) and halloysite nanoclay and bioinert materials Alumina (AL2O3) and Zirconia (ZrO2), each of them with various weight ratios (1,2,3,4 &5)% to the polymer matrix PMMA. The best ratios were selected, and then a hybrid was preparing Composite red from the best ratios from each group. Thermal properties, including thermal conductivity and Thermomechanical Analysis (TMA) technology, have been studied. The results showed that adding 3% Hydroxyapatite (HA) and 5% halloysite nanoclay to the polymethacrylate (PMMA) mer leads to an increase in thermal conductivity. It was also found from the Thermomechanical Analysis
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Consuming of by-product or waste materials in highway engineering is significant in the construction of new roads and/or in renovations of the existing ones. Pulverised Fuel ash (PFA), which is a by-product material of burning coal in power stations, is one of these materials that might be incorporated instead of mineral filler in hot asphalt mixtures.
Two types of surface course mixtures have been prepared one with conventional mineral filler i.e. ordinary Portland cement (OPC) while the second was with PFA. Several testings have been conducted to indicate the mechanical properties which were Marshall Stability and Indirect Tensile Strength tests. On the other hand, moisture damage and ageing have been evaluated
... Show MoreThis paper reports on the experimental study, which conducted a series of triaxial tests for the asphalt concrete using hydrated lime as a mineral additive. Three HMA mixes, prepared by the specification for wearing, levelling and base layers, were studied under three different temperatures. The test results have demonstrated that, compared with the control mixes excluding HL, the permanent deformation resistance of the HL modified mixes has significant improvement. The deformation has been reduced at the same load repetition number, meanwhile the flow number has been considerably increased. The degree of improvement in permanent deformation resistance using HL is more pronounced at high stress deviation states and high temperature.
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Objective conditions for the possibility of punishment are legal or material facts –positive or negative that depart from the activity of the offender. The legislator comments on their subsequent verification on the formation of some crimes the possibility of.The application of punishment to the offender , but although they are facts of an object nature that approach and overlap with many systems and cases , they are distinguished by a certain subjectivity that differentiates them from each case that may seem similar or approach them. To clarify the ambiguity that may surround these conditions , Which may lead to confusion between them and what be similar to other cases due to the common effect that they have in common , which is the f
... Show MoreAims current research to identify the mistakes coding contained in the reading first grade. Encoding knew that he had failed in Retrieval or identifying information, the researcher diagnosis of mistakes and presented to a group of teachers first grade and they have an appropriate adjustment and using the percentage shows that the agreement on the mistakes ratio and adjusted researcher recommended a set of proposals and recommendations can work out the future for the advancement of scientific level
The performance and durability of the asphalt pavement structure mainly depend on the strength of the bonding between the layers. Such a bond is achieved through the use of an adhesive material (tack coat) to bond the asphalt layers. The main objective of this study is to evaluate the effect of moisture in conjunction with repeated traffic loads on the strength of the bonding between asphalt layers using two types of tack coats with different application rates. Using the nominal maximum size of aggregate (NMAS), the layers were graded (25/19) and (19/9.5) mm. The slabs of multilayer asphalt concrete were prepared using a roller compactor using two types of tack coats to bond between layers, namely rapid curing cut back a
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