Advanced Materials Research Vols. 374-377

Abstract: Concrete is the most consumed building material worldwide today, which durability has been paid close attentions for a long time. Currently，the design lifetime of many buildings is over 100 years. At present, many projects adopt preservatives to extend the durability of concrete. the paper makes contrastive studies on mechanical properties, ASTM flux, RCM chloridion diffusion, Permit in situ chloridion permeability, Autoclam water absorption, and freezing & thawing resistance between preservatives-added and non-preservative concretes at different typical strengths; and concludes correlations between the preservatives at different strengths and the durability of concrete, thus to evaluate the influence of various preservatives on the durability of high-performance concrete.

Abstract: With the experiments of dynamic shear rheometer(DSR), bending beam rheometer(BBR) and Brookfield rotary viscometer, the rheological performance of Buton Rock Asphalt (BRA) modified asphalt is tested and analyzed. The results indicate that the high temperature PG grades, the anti-rutting indicator and the viscosity are all increased, the high temperature stability is enhanced greatly and the temperature sensitivity is reduced after the addition of BRA modifier. Furthermore, the change rate increases with the increase of the additive; the creep stiffness modulus increases and low-temperature performance decreases at a low temperature, so the dosage of BRA should be appropriately considered in the process of application.

Abstract: Based on the red clay of Wuhan reinforced by Ionic Soil Stabilizer, the red clay soil is treated by different matches of ISS at first, then is tested in the Atterberg limits test and dynamic triaxia test. The results show that the plastic index decreases, and the red clay were greatly improved under the dynamic condition, the maximum dynamic shear modulus ratio acquired an incensement of 27.72% on average after mixing the ISS into the red clay. In addition, It was concluded that the confining pressure influenced the dynamic shear modulus and damping ratio to a certain extent. Given the same strain conditions, with the incensement of confining pressure increases, the dynamic shear modulus increased and the damping ratio decreased. Moreover, when plotting the dynamic shear modulus versus the dynamic shear strain, the similar curve can be formed for both the natural soil and the modified one, the dynamic shear modulus monotonously decreased with the incensement of the dynamic shear strain. However, the value of dynamic shear modulus differed in the same shear strain between the natural soil and the soil modified by ISS.

Abstract: The paper investigates positive effects of three kinds of fibers on the performance of asphalt concrete mixture, which include mineral fiber (Fiberand^®), lignin fiber and polyacrylonitrile (Dolanit^@AS). The contrast experiments of AC-13 SBS modified asphalt mixture added fibers were carried out. The results reveal that the pavement performance can be improved remarkably if appropriate fibers are added into the asphalt mixture. The method of determining optimum mixture ratio was proposed on the basis of road performance of asphalt concrete. It is more reasonable to adopt comprehensive indicator containing stability and dynamic stability in determination of the optimum mixture ratio of asphalt concrete.

Abstract: OGFC can reduce traffic noise which has very high air-void contents to absorb tire-pavement noise. This paper proposes maximum aggregate size and aggregate gradation of OGFC with the objective void of 20%. Performance of modified asphalt and best asphalt-aggregate ratio are also proposed with four kinds of modifiers, including SBS, rubber, EVA and PVC. The absorption coefficients of the four kinds of OGFC and the dense-graded Marshall specimens were tested with standing wave tube. Then their sound absorption performances were compared.

Abstract: The polyacrylamide/starch-acrylic acid graft copolymer/bentonite composites with different concentrations of the bentonite and starch-acrylic acid graft copolymer were prepared by in-situ polymerization. The influence of the concentration of the bentonite and starch-acrylic acid graft copolymer on the water absorbency was investigated. The water absorbency of 115 g/g could be achieved with the composite composed of 50wt% bentonite, 17wt% starch-acrylic acid graft copolymer and 33wt% polyacrylamide. The excellent absorption and retention performance of the composite makes it potential to be applied in the model of Rain garden.

Abstract: In order to avoid the phase separation of the high density-polyethylene modified asphalt, a composite material modifier was prepared in the melt blending process with High density-Polyethylene (HDPE) and Styrene-butadiene-styrene (SBS) and a filler of Carbon black (CB). The storage stability of composite material (HDPE-SBS) modified asphalt was investigated by hot storage stability test and optical microscopic observation. The storage-stable mechanism of HDPE-SBS modified asphalt was analyzed also. The experimental results indicated that the difference of the softening point after storing at high temperature for 48h was very small. Micrographs of HDPE-SBS modified asphalt demonstrated that HDPE-SBS composite modifier particles dispersed uniformly and compactly and there were no obvious phase separations in the modified asphalt within a certain CB content range.

Abstract: Based on the Bailey method for aggregate grading design and evaluation, the parameter "reserved voidage" is used in porous asphalt method design. The paper studies the relationship between the three parameters (reserved voidage, blend by volume of the coarse aggregates totaling 100.0% and chosen unit weight of coarse aggregate) and the pavement performances, such as deformation, resistance at high temperature, low-temperature anti-cracking and moisture susceptibility of porous asphalt mixture. The test results indicate that the porous asphalt mixture designed by the modified Bailey Method is of the characteristics of air void easier to control and superior performance.

Abstract: Hydrotalcite/poly(sodium acrylate-acrylamide) composite was synthesized by using inverse suspension polymerization method under different hydrotalcite content, neutralization degree and ratio of monomer with orthogonal experiments. The surface morphology, structure and humidity controlling properties of composite were observed and determined. The results show that hydrotalcite/poly (sodium acrylate-acrylamide) composite is in an irregular block like structure with different size. During the polymerization process, acrylate and acrylamide monomers are successfully intercalated into the interlayer of hydrotalcite, and the distance of (003) hydrotalcite plane is increased from 0.766nm to 1.146nm. The impact of three factors on the humidity controlling behavior of composites increases by the order of ratio of monomer, hydrotalcite content and neutralization degree. The optimum preparation parameters are hydrotalcite content of 4%, neutralization degree of 90% and ratio of monomer in 9:1.

Abstract: In this study, the thermal properties of a kind of new geotextile materials, so called controlled permeable formwork (CPF), were studied. Thermo-gravimetric analysis showed that the weight of CPF didn’t change much between 0~350 °C. Dynamic mechanical analysis showed that the storage modulus of CPF reduced from 25 MPa to around 10 MPa when the temperature rose to above 100 °C. The strength of sample decreased slightly with the increase of the temperature. The breaking elongation changed slightly with a maximum at 80 °C. The CPF showed excellent thermal stability and was suitable for general use in construction work.