Reduced adhesion properties between aggregate particles and bitumen binders, and reduced cohesion within the bitumen binders in asphalt mixes result in stripping and segregation distresses in road pavements. These will ultimately result in pothole formation and other severe distress in pavements. In this research, with the aim of determination of adhesion and cohesion properties between aggregate particles and bitumen binders, the Pull-off testing method, which is commonly used in characterizing road marking materials, was used to determine tensile strength values that are created between aggregate particles and bitumen emulsions. Two conventional cationic bitumen emulsions of rapid and medium breaking types were used as control binders. These were then modified using a latex liquid additive at various percentages. Two aggregate types were used, namely granite and a dolomite type. Their mineralogy was determined using the XRF testing method. In addition, the role of other parameters, such as curing time and curing temperature, were determined too. Pull-off testing results showed that modification of bitumen emulsions with %3 latex provided increased adhesion properties and increased durability between bitumen emulsion and the two aggregate types that were selected in this research. It has also resulted that interaction between aggregate particles and the bitumen emulsions was great where latex modified bitumen emulsions were used. By comparing the role of the two aggregate types, it resulted that the dolomite aggregates provided superior adhesion properties. It was concluded that the role of curing time and temperature were dominant in providing adequate adhesion properties between bitumen emulsions and aggregate particles. The increase was more dominant in samples containing latex-modified bitumen emulsions.

In this paper, effects of curing methods (i.e. curing at ambient temperature (A), in oven (O) and in boiling water (BW)), NaOH solution concentration (i.e. 8 and 12 moles/liter) and disc thickness (i.e. 1, 2 and 3 cm) on Pull-off strength (POS) of the geopolymer concrete containing Ground Granulated Blast Furnace Slag (GGBFS) and Natural Zeolite Powder (NZP) have been investigated. The results show that the value of the POS obtained from the 3 cm thickness disc is on average 2.6% higher than that obtained from the 2 cm thickness disc. This implies that the discs with thicknesses of 2 and 3 cm have given approximately equal values of the POSs. Moreover, the value of the POS obtained from the 2 cm thickness disc is on average 28.4% higher than that obtained from the 1 cm thickness one. Based on the results obtained from the 2 cm thickness disc: a) the ratios of the POSs of the samples cured in boiling water and oven to that of the specimen cured at ambient temperature have been obtained on average equal to 1.383 and 1.089, respectively. b) as 20% wt. of the GGBFS is substituted by the NZP, the value of the POS reduces by an average of 16.29%. c) as the NaOH solution concentration increases from 8 to 12 mole/liter, the value of the POS increases by an average of 14.48%. From the results, there is a strong nonlinear relationship between the compressive and Pull-off strengths of the geopolymer concrete.

One of the maintenance methods for cracked pavements is application of overlay on its surface. In this situation the overlay is open to the cracks with the shape of previous cracks. One of the most important methods for prevention of these cracks (that named reflective crack) is using geosynthetics. The bonding of geosynthetic between asphaltic layers has noticeable importance when the geosynthetic is used for reinforcement. Pull out is a common test in order to find the amount of geosynthetic-soil bonding، though this test is not common for geosynthetic-asphalt bonding. In this research a Pull out test device has been developed in Amirkabir University of technology and used to evaluate the bonding of geosynthetic-asphalt with different geosynthetic grid sizes. Effect of three important parameters on Pull-out test results has been evaluated and compared. Based on the findings of this research the most effective parameter is temperature. The next effective parameter is tack coat application rate. Based on the ANOVA the conflict between parameters has been studied. The most important conflict was belonging to the conflict of temperature and the tack coat application rate. Based on the mentioned studies a model has been developed for maximum bonding and temperature and tack coat application rate.

In this study, a statistical analysis of the prediction of compressive strength of self-compacting steel fiber reinforced concrete (SFRSCC) based on Pull-off test results using linear and nonlinear regression models is presented. For this purpose, an extensive test program was performed including different amounts of cement and aggregate size along with steel fibers in the amounts of 0, 30, 50 and 80 kg / m3. Aluminum and steel discs with diameters of 50 mm and 70 mm with different thicknesses were used. In addition, the effect of partial core depth on Pull-off resistance was investigated. The effects of SFRSCC properties and test parameters are included in the proposed equations as dimensionless variables. The results showed that both linear and nonlinear regression models have high potential as a reliable tool for predicting SFRSCC compressive strength based on Pull-off experiments. In the multiple linear regression model for predicting SFRSCC compressive strength for aluminum disc, the most effective parameter is F / C factor and da / D factor has the least effect and for steel disc, the most effective parameter is F / C and the lowest effect is related. To the da / D factor. However, the most accurate results are obtained from nonlinear equations compared to linear models.

Several full porcelain systems are available in the market, among which In - Ceram (Vita Zahnfabrik, Bad Sackingen, Germany), has been introduced to show unique properties including: fine esthetic and high quality strength. In this investigation Flexural strength of In - Ceram core material has been evaluated by four - point bending test with Instron (Model 1195) machine. Samples were provided in form of ten bars of core material with the dimension of 30 × 6 × 2.5 mm.Results obtained show that the mean value of 538 ± 42 (MPa), of force is required to hit its resistance limit which is higher than similar values in other dental ceramics, within acceptable clinical range.

Background and Aim: ZOE has been used in different fields of dentistry for many years. A locally produced component (Zoliran) has been recently introduced to the marketwith similar characteristic to the original Zonalin. Because of a lower cost involved to use Zoliran cement and its availability, confirm reliability of its physical properties. This investigation was designed to assess the Compressive strength of Zoliran cement in comparison to Zonalin cement as the standard material. Materials and Methods: Five samples with dimension of 4mmx6mm of each cement were provided and stored in distilled water in 370C±10C for a period of 24 hours. The lowest load of force was registered as the reference to which the sample could be broken by(according to the criteria No: 30 of ANSIIADA). The value of compressive strength was then calculated using the following formula (K =4F/πD2 ). Results: The mean compressive strength of five samples was measuredas: 14.33 Mpa for Zoliran cement and 31.83 Mpa for Zonalin cement. The mean compressive strength of Zonalincement was significantly higher than the mean suggested in ANSl/ADA Specification No.30. The mean compressivestrength of Zoliran cement was also lower than the mean value registered in ANSI/ADA SpecificationNo.30. Conclusion: Compressive strength of Zoliran cement was significantlylower than that of Zonalin cement. Further tests are required to compare the other physical properties of this material before it can be clinically recommended.

The bond between concrete and reinforcing steel is essential for the composite action in reinforced concrete structures. In the present study, the effects of super-plasticizer additive on the steelconcrete bond strength is experimentally investigated. A total of 18 Pullout samples are prepared in two concrete mix design cases, including ordinary and high-strength concrete. The used steel bars are of diameters 8, 10 and 12 mm, which are embedded inside the concrete in a length five times the rebar diameter. The steel-concrete bond strength is evaluated using direct Pullout test method with the universal testing machine. Besides preparing the Pullout specimens, 5 standard cube samples of concrete are casted to examine the concrete compressive strength and dimensions of the hardened concrete cubes. The specimens are tested at the 42-day ages and the slip-force curves are obtained using the Pullout test. The maximum force and the corresponding slip, bond stress and other important parameters are determined and discussed for the different studied conditions. The results indicate that the rebar-concrete bond strength decreases by increasing the rebar diameter and the super-plasticizer additive has an important effect on the bond strength. For instance, the average bond strength for the concrete mix containing superplasticizer is 2. 3 time of that for the normal concrete.

The interaction parameters between soil and reinforcement at their interface play a critical role in influencing the mechanical behavior of reinforced soil systems. Interaction parameters between soil and reinforcement influence reinforced soil behavior mechanically. In this research, the effect of the size of soil grains and the stiffness of the reinforcement on the Pull-out resistance of the reinforcement from the soil has been investigated in a laboratory. The Pullout resistance of three types of reinforcements with different stiffness in three types of soil with different grain sizes has been investigated. Pull-out tests have been performed at three stress levels of 50, 100, and 150 kPa. To investigate this issue and determine an evaluation for the stiffness of the reinforcement, a device has been built to measure the penetration of solid soil grains in the reinforcement. The results of the tests show that the penetration of soil grains into the reinforcement has a significant impact on the resistance of the reinforcement to being Pulled out of the soil. The amount of penetration of solid soil grains into reinforcement increases by reducing the stiffness of the reinforcement and increasing the size of the diameter of the soil grains. For each specific vertical stress level, the greater the penetration of solid soil grains into reinforcement, the higher the Pull-out strength of that reinforcement. The results show that with the increase in the diameter of the solid grains of the soil, the Pullout resistance of the reinforcement has also increased, but this increase has been more significant in the case of reinforcement with lower stiffness compared to reinforcement with higher stiffness. Also, the difference in the Pullout resistance of three reinforcements with different stiffness in fine-grained soil was less than the difference in the Pullout resistance of three reinforcements in coarse-grained soil, which indicates the simultaneous effect of reinforcement stiffness and soil grain size on Pullout resistance.