Applied Mechanics and Materials Vols. 357-360

Abstract: norganic polymer concrete of a new environment-friendly material has been the hot issue in engineering research so far. For this new material, the main job of the paper includes: we design mixture ratios of inorganic polymer concrete by ourselves, testing the concrete in the age periods of 3, 7, 28 d. The results indicate that this kind of material strength develops mainly in the first 3 d, the strength grows slowly in the later stage; the dry shrinkage of the configured concrete properties are measured, the curve of dry shrinkage shows that the dry shrinkage occurs mainly in the first 14 d and develops slowly in the late; And measure the expansion performance of the concrete member mixed the different categories expansive agent, the results show that the volume growth of mortar specimens to join HCSA expansion agent are obvious; Test results provide a certain basis for the inorganic polymer concrete of micro expansion.

Abstract: This paper gives a comprehensive investigation on the effects of undercalcined MgO-based expansive agent (UMEA) on the shrinkage and associated cracking behavior of cement based materials, including length change under drying condition and restrained condition, and cracking under single-ring restraint. Experimental results showed that the UMEA could reduce the drying shrinkage as well as restrained shrinkage of cement based materials effectively. The measured shrinkage reduction was up to 55.3% at the age of 180d of drying. It was also found that the addition of shrinkage could effectively improve the shrinkage cracking resistance of cement based materials even under drying condition. The experimental results of autoclaving testing showed that the UMEA has a larger dosage of stability. If the dosage in cement is controlled according to the requirement of concrete construction, the UMEA can be used to compensate the shrinkage as designed.

Abstract: In this paper, the effect of fly ash with different grades and dosage on early shrinkage and late shrinkage deformation of commercial concrete were studied. The effect of fly ash with different grades and dosage on volume stability of commercial concrete was assessed by using the test method of shrinkage cracking, and the causes and mechanism of the effect were analyzed.

Abstract: Grouting fill is one of the main methods of coal gob treatment. The grouting properties directly affect the effect of grouting treatment. Cement-fly ash grout is widely used in the treatment of coal gob. But in many gob grouting fill projects, due to the lack of fly ash, we need to look for other low-cost grouting materials. Study was made through laboratory experiment on the properties of cement-coal gangue materials used for the gob grouting. In this paper, the correlation of water-solid ratio, cement content, admixture, concretion compression strength, setting time, viscosity, water segregation rate and hardening rate is discussed in the case of use of large gangue content cement. The test results show that compared with the grout not go through the activation process, the blended cement grout mixed with coal gangue powder activated by low temperature and mechanical crushing has high concretion compression strength. Water glass has a great effect on the viscosity, initial setting time and final setting time, which can be used to adjust the grout properties to accommodate grouting environment requirements. This grout has the advantage of wide range sources of raw materials, and can be used to solve the lack of fly ash and gangue resource utilization problems.

Abstract: The crack under the action of non-load was the most significant factor to affect the concrete frost resistance durability. The Orthogonal Experimental Design (OED) Method was used in this paper to optimize the match ratio of the additive and to increase the concrete frost resistance durability by adding the PF, the FA, the WA in the concrete and replacing the cement of ordinary silicate with the compound cement. It offers the reference value to the development of the hydraulic concrete.

Abstract: In this paper, the effects of the water-reducing agent on the hydration property and the formation of the ettringite crystal of the concrete C3A were studied. Based on the thermometry analysis, the experiments of the effection of the hydration temperature on such concrete with both naphthalene- and polycarboxylate-type superplasticizers were conducted. The results could be drawn that the additives could prevent the slurry being hydrated in 1h, and decrease the hydration temperature. With the increasing of the additives, the hydration-inhibitory action of the additives was improved, too. The effect of the naphthalene- and polycarboxylate-type superplasticizers on the solubility property of C3A was also studied with EDTA titration, and the results showed that they can suppress the crystallization of the ettringite.

Abstract: For coal gangue sintered brick production process, the effect factors are discussed, the best process factors are: coal gangue maximum size should be less than 3 mm, suitable for calorific value for 400 ~ 600 kcal/kg; Forming water is not more than 17%, extrusion pressure is not more than 3.0 MPa; Dry air brick moisture content should be less than 6%; Firing temperature should be controlled in more than 1050 °C.

Abstract: The novel surfactants of sulfonated methylnaphthalene-formaldehyde condensates modified with poly (ethyleneglycol) monooctylphenyl ether (OP-10), 4-octylphenol or octadecylamine were synthesized as anionic emulsifier for the preparation of asphalt emulsions and cement mortar. The experimental results revealed that the modified methylnaphthalene sulfonate formaldehyde condensates (MSFC-OP10, MSFC-OCP and MSFC-OAM) containing a substantial amount of hydrophobic and lipophilic groups in the main chain would exhibit a superior effect both in dispersability and emulsifying property. When cement is mixed with the emulsified asphalt containing MSFC-OP10, MSFC-OCP or MSFC-OAM, the free as-synthesized condensates in the emulsified asphalt exhibited a fairly good dispersing performance and this emulsified asphalt appeared to be relatively stable as well. The presence of either MSFC-OP10, MSFC-OCP or MSFC-OAM in the asphalt emulsion would not only markedly improve its stability, delay its demulsification process, but also would upgrade and restrain both the settlement and stratification of the mixed mastics.

Abstract: The work described in this document forces on composite strengthening technique of recycled aggregate. In this experiment, recycled aggregates are soaked in different types and different concentrations of nanomaterials to strengthen. This research estimates the strengthening effects by comparing the properties of recycled aggregate soaked in different materials, and proves that the composite proportioning has better effect.

Abstract: This paper studies on the technical and economic analysis of fiber reinforced polymer (FRP) substation framework. Firstly, based on the comparison of the material performance and price, we select the suitable fiber and resin as the main building material for substation framework. Then on the basis of numerical simulation, the bearing capacity of FRP substation truss-column under axial compression and bending is researched, and the initial geometric imperfection is considered in the models. Finally, the behavior of the typical two-span FRP gantry of substation is analyzed, and the economy of FRP substation framework is compared with the steel gantry which owns the same capability.