Advanced Materials Research Vols. 250-253

Abstract: A new kind of ultra high performance concrete containing limestone powder was studied in this paper. The results show that the compressive strength of the ultra high performance concrete containing limestone powder is higher than 120MPa; the hydration activity and the accelerating effect of limestone powder are obvious under the condition of high temperature. The limestone powder hydrated and formed calcium monocaboaluminate hydrates. The cost would be reduced when adding certain amount of limestone powder when confect ultra high performance concrete. It is economical and feasible.

Abstract: In this paper, polyester fibers (PET) were treated with low temperature plasma firstly. Then, these plasma treated PET fibers were coated with polypyrrole (PPy) by pyrrole deposition polymerization to impart conductive property to the fibers. Interfacial shear strength (ISS) between PET fiber and asphalt was measured by single fiber pull out test. XPS and SEM were used to characterize the fibers’ surface configuration and analysis the functional groups. The results show that plasma-treatment has a strong effect on the surface morphology, surface elements, electrical property and the ISS.

Abstract: A new type of poly (acrylic acid-co-acrylamide) was synthesized by copolymerization method using acrylic acid (AA) and acrylamide (AM) as monomer. Synthesis technology was as follow: the acrylamide and acrylic acid molar ratio was 0.3-0.4, the temperature was 55-60°C, the degree of neutralization of AA was 70%, the potassium persulfate and monomer mass ratio was 0.2%-0.3%, the aluminum hydroxide and monomer mass radio was 0.03%-0.05%. The water absorption was more than thousands of times.

Abstract: Based on the research results of the microstructure of concrete, and considering the characteristics of rubber modified concrete, this paper proposed an analysis model of the microstructure of rubber modified concrete. According to the analysis model, comparing the influence of incorporation of rubber particles, no incorporation of rubber particles on the mechanical properties of concrete, the analysis result was in good accord with the experimental results, which confirmed the correctness of analysis model, then the mechanical properties of rubber modified concrete were analyzed.

Abstract: The rheological properties of brucite fiber asphalt mastics are studied by the Brookfield viscosity test in this paper. The results show that at 105°C and 120°C, brucite fiber asphalt mastics shows the characteristics of non-Newtonian fluid. At 135°C and 150°C, it shows the characteristics of Newtonian fluid gradually. When the temperature is higher than 150°C, the asphalt mastics has fully manifested the characteristics of Newtonian fluid. The viscosity increases with the increasing of the dosage of brucite fiber. The value of ZSV increases with the increasing of the dosage of brucite fiber. According to the change law of ZSV, the anti-rutting performance of asphalt mastics is improved by the addition of brucite fiber.

Abstract: Desulfuration residues were used as aggregate to produce Non-autoclaved aerated concrete. The effects of water-hinder ratio, casting temperature on the gas forming behavior, and those of desulfuration residue content on the compressive strength and bulk density of aerated concrete were investigated. The types of the hydration products and the microstructure of Non-autoclaved aerated concrete with desulfuration residue were investigated by means of X-ray diffraction and scanning electron microscope. Results show that the optimum replacement amount was determined as 50% and at this rate the compressive strength, bulk density of Non-autoclaved aerated concrete were measured as 2.83 MPa and 543 kg/m³. The hydration products of Non-autoclaved aerated concrete with desulfuration residue are C₂SH (A) and C₂SH (B) along with ettringite and hydrogarnet phases.

Abstract: Polycarboxylate-based superplasticizers are synthesized by radical graft copolymerization reaction, and the products are divided into ester series (PC-1) and ether series (PC-2) on the basis of different big monomers. This article studies on influence of the different composition and dosages of the synthetic superplasticizers in the self-compacting concrete (SCC). The results show that the requirements of SCC workability can be achieved through simple adjustment kinds and dosages of the synthetic superplasticizers under the given mix proportions and the raw materials. And the main mechanism of the polycarboxylate-based superplasticizers is steric hindrance effect.

Abstract: The general attributes of calcium silicate products have been investigated in several studies. In this paper, we propose to use a specific modifier i.e. lithium polysilicate solution in order to examine and improve compressive strength of sand-lime bricks. The research was examined by scanning electron microscope (SEM). The main objective was to determine the phase composition in the structure of the sand-lime products.

Abstract: At the present, Portland cement-water glass double solution grouting materials have many problems, such as the instability of gelation time and of products, and poor groundwater-corrosion resistance performance, etc. A way to improve the performances of double solution grouting materials was studied by adding metakaolin into the systems. Based on the rapid gelation performance of Portland cement-water glass and the durability of alkali-activated salic cementitious materials, an ideal structural model of the novel anti-aqueous dispersion and anti-aqueous dissolution grouting material (AAGM) was established. Series of experiments were prepared to verify the Na⁺ solidification and water-corrosion resistance performance of the metakaolin-water glass double solution grouting materials which combined with cement. The results indicated that the compact structure of AAGM was composed of a dominant ingredient of (Na,Ca)-Si-Al-H zeolite gel and a minor part of C-S-H. Moreover, it was shown that the AAGM had hydrated product of low solubility and compact microstructure tested by Fourier transform infrared spectra (FTIR) and transmission electron microscopy (SEM), which proved the well anti-aqueous dispersion and anti-aqueous dissolution performance.

Abstract: Based on the analysis of chemical constituents and mineral composition, a new disposal method of alumina red mud added in cement stabilized macadam base was put forward. Through experiments of compressive strength, dynamic elastic modulus, splitting intensity and resilient modulus, mechanical properties of alumina red mud- cement stabilized macadam base and base performance affected by alumina red mud dosage were studied. Also, the strength formation micro-mechanism of alumina red mud-cement stabilized macadam mixture was explored by scanning electron microscopy (SEM). The results indicate that alumina red mud-cement stabilized macadam mixture has good mechanical properties; its early compressive strength, early splitting intensity, dynamic elastic modulus, resilient modulus are improved obviously with alumina red mud mixing; the mixing amounts of alumina red mud and cement are significantly affected mixture strength and the optimum mixing amount is respectively 10~12% and 5~6%; alumina red mud can promote cement hydration and hydrates generation. it not only is used as interstitial material among aggregates，also as binder closely linked aggregates through the spatial reticular structure formed by red mud and cement hydrates, which enhance mixture strength.