This study is the second stage of the paper “Studying the Effect of Rubber- Silicone on Physical Properties of Asphalt Cement”. The present study examines the effect of additives on asphalt mixture performance. Asphalt mixture has been designed by Marshall Method for determining the optimum asphalt content and geophysical properties of mix according to ASTM (D-1559). Rubber-silicone at different percentages (1%, 2%, 3% and 5%) was added to asphalt binder. Six specimens of asphalt rubber silicone mixture (ARSM) for each percentage are prepared and evaluated according to Marshall method. Diametric tensile creep test ASTM (D-1075) at 60 Co was used to evaluate permanent deformation and modulus of elasticity for ARSM. The study showed that the Rubber-Silicone has more effects on performance of asphalt mixture by increasing the Marshal stability, air voids, and reducing the flow and bulk density compared with the original mix. It also increases the flexibility properties of the mix and this appears from reducing the permanent deformation at test temperature (60C), the reduction percent is about (30 to 70) %.
In this current experimental research, the amount of improvement in the thermal conductivity of HEC hybrid epoxy resins was studied by adding copper oxide nanoparticles CuONp and carbon nanotubes (CNTs) as hybrid additives in different proportions to select the sample with the highest thermal conductivity value to include it in the design of the Flat Plate Solar Collector FPSC as Thermal Interface Material TIM reduces thermal resistance between the absorber plate and the tube. Four groups of samples were prepared using a mass balance with a sensitivity of 0.01g and a magnetic mixing device, then poured into cubic plastic molds to take the shape of the sample. The first group consists of one sample of pure epoxy to calibrate the thermal properties testing device through it. The second group consists of five samples of epoxy loaded with CNTs by weight (1, 3, 5, 7.5, 10) %. The third group consists of five samples of epoxy loaded with CuONp with weight percentages of (1, 3, 5, 7.5, 10) %. The fourth group consists of five samples of epoxy loaded with CuONp and CNTs combined in weight percentages of (1, 3, 5, 7.5, 10) %. The thermal conductivity of the samples was measured experimentally using the hot disk analyzer technique to measure thermal specifications. After comparing the thermal conductivity values of the samples, the highest value was 1.57 W/mK for the HEC sample loaded with 10% CNTs, which represents 9.23 times higher than pure epoxy
The construction of pavement layers on subgrade soil with good characteristics decreases the thickness of these layers, which in turn lowers the cost of building and maintaining roadways. However, it is impossible to avoid constructing pavements on unsuitable subgrade due to a number of limitations. Using conventional additives like lime and cement to improve subgrade properties results in additional costs. As a result, utilizing by-products (cement kiln dust and reclaimed asphalt pavement) in this field has benefits for the environment, economy, and technology. Large amounts of cement kiln dust (CKD), a by-product material, are produced in Portland cement factories. On the other hand, large amounts of reclaimed asphalt pavement (RAP) are accumulated as a result of the rehabilitation of old roads. This paper discusses using CKD and RAP to improve the characteristics of poor subgrade layers by conducting a series of Unconfined Compressive Strength (UCS) and California Bearing Ratio (CBR) tests on samples of natural soil and soil stabilized with different percentages of CKD and RAP with different curing times to investigate their impacts on soil properties. The curing was carried out by wrapping the stabilized samples with several layers of nylon and then placing them in plastic bags at room temperature. The compaction results illustrated that the addition of CKD increases OMC and decreases MDD, in contrast to RAP, which decreases OMC and increases MDD. The addition of CKD and RAP led to a significant and unexpected increase in the CBR values. The results show that the soaked and unsoaked CBR values improve from 3.4% and 12.1% for natural soil to 220.1% and 211%, respectively, after adding 20% CKD and curing the samples for 28 days. Also, the addition of 25% RAP to soil-20% CKD blend increased the soaked and unsoaked CBR values to 251% and 215%, respectively. All the additions resulted in a significant reduction in swelling.
Addition of 40% of Phosphogypsum ( Pg ) and Cement Klin dust ( CKD) to Asphalt has given encouraging results including penetration , softening , Flash point an fire point identical to the accepted properties of industrial asphalt. Chlorination of Natural Asphalt at 1.5 hr the same additive of 40% in the presence of Fe2O3 as catalyst have affered optimizing rhealogy and thermal properties. The FT-IR and UV identifications have indicated the existence of clear groups as aresult of chlorination and additives. The microscopic study for floor samples have shown the good atomic distribution to floor asphalt .Generalty results on the modified natural asphalt ( Heet- Abo- Aljeer ) have proved the capability of using it in paving instead of Industrial asphalt .