Key Engineering Materials Vol. 861

Abstract: There are microfractures and fractures in the carbonate formation of M oilfield, which are easy to cause collapse and borehole instability. On the basis of the liquefiable cleanflo drilling fluid system for open hole completion of horizontal wells designed in the early stage, this paper has carried out the research work of matching acidizing completion fluid system. In this paper, the influence factors, cleaning ability, compatibility, acidizing situation and protection effect of acidizing completion fluid system are evaluated in laboratory. The way of density adjustment and specific dosage of NaCl and hcoona were established to inhibit the formation of salt crystallization. HTA solid acid and JCI are used to counteract each other to reduce the corrosion of casing steel. The core displacement results show that the permeability recovery value of carbonate core after completion fluid treatment can reach 97.54%, and that of sandstone core after treatment can reach 114.7%. Moreover, the completion fluid system also has a certain acidizing effect, which can not only clean and remove the plugging, but also serve as the early induction of acidizing and stimulation.

Abstract: In view of the particularity of deep-water thick rock reservoir, in order to deal with the problem of poor reservoir stability and serious loss of drilling fluid in the drilling fluid design of M oilfield, this paper has carried out the reservoir inhibitor optimization evaluation test for the salt resistant high-density drilling fluid which has been designed and optimized, and also carried out the appropriate selection of plugging materials and plugging effect test for the loss of salt gypsum layer. The results show that the stability of saturated salt water drilling fluid in the salt gypsum layer with shale can be effectively ensured by the combination of CPI and uhib inhibitors within 2%. At the same time, FloSeal, a new plugging agent for 1-2mm fractures, is selected, and its plugging loss capacity is stably controlled below 30ml.

Abstract: Monolithic electrodes for oxygen evolution reaction (OER) have been successfully synthesized by hydrothermal method. Prolonging the hydrothermal duration and subsequent annealing treatment can increase the OER activities and stabilities of the samples. The IrO₂/Ti-60h@400 shows excellent performance, which requires an overpotential of 391 mV at 100 mA cm^-2, and could keep good activity at 200 mA cm^-2 for 40 hours in acid electrolyte.

Abstract: In this study, according to the climate characteristics of the micro-frozen area, the winter construction of cast-in-place beams is based on heat preservation, supplemented by electric tracing band (ETB) in weak areas, and verified by the model experiment. According to the situation of the construction site, winter construction techniques are formulated and optimized. The winter construction techniques are widely used in the reconstruction and expansion of Beijing to Shanghai expressway, Xintai to Ningyang expressway, Xintai to Taierzhuang expressway and other projects. No diseases in winter construction occurred in all application projects. The techniques are cost-effective and environmentally friendly.

Abstract: The sound absorption performance of porous asphalt concrete (PAC) is inseparable from the sizes of voids, as different sizes of voids have different absorption effects on noise in different frequency bands. However, the relationship between the two is not clear. In this study, the equivalent diameter of voids was obtained by the proposed image segmentation algorithm based on the square area, then grey entropy method was used to analyze the effect of different equivalent diameter of voids on the sound absorption performance of PAC in the frequency range of traffic noise. The results show that with the increase of air voids, the peak and average sound absorption coefficient of PAC increase, the sound absorption performance of PAC is improved; and the sound absorption performance of PAC is mainly affected by the equivalent diameter of voids of 3-4mm.

Abstract: Porous asphalt pavement is widely used in domestic engineering, whose repair technology is still a problem in engineering application. Rut specimens for porous asphalt pavement are made, so the actual repairing condition of porous asphalt pavement can be simulated after slotting and repairing by open-graded cold mend material. In addition, the repair efficiency of open-graded cold mend material was verified. The results of the pullout test show that when the spraying dosage is 0.75L/m², the bond behavior of bonding oil is best excellent. The Accelerated Loading Facility (ALF) indicated that the cold mend material has favorable abrasion resistance properties, and the abrasion resistance is less effected by the spraying dosage of bonding oil. Meanwhile, it’s reveled that the permeability coefficient of rut specimen repaired by cold mend material decreases with the increase of spraying dosage of bonding oil in the permeability test, and too much bonding oil will seriously affect the rut specimen’s original permeability.

Abstract: In order to explore the influence of a new mixed type antifreeze material on the flexural strength of concrete for road, the orthogonal design method was used to conduct experimental research on six factors including the water-binder ratio, the antifreeze material content, the fly ash content, the feeding process, the shape of the antifreeze material and the pre-absorption of antifreeze material. The influence degree of various factors on the flexural strength of concrete was studied, and the mixing ratio design method of concrete for road mixed with the antifreeze material was given. It was found that the water-binder ratio is the main factor affecting the strength of the concrete and that when the amount of antifreeze material is less than 15%, the effect on the strength is small. The influence of other factors on the strength is greatly influenced by the interaction of water-binder ratio. When it comes to the mix design, the content of gelling material is 500 kg/m³, and the water-binder ratio changes from 0.35 to 0.43 under different traffic levels. The recommended antifreeze material content and fly ash content is 10% and 15% respectively. It’s also suggested that the antifreeze material should be pre-absorbed, and the cement sand and stone be mixed before the antifreeze material is put into the mixing.

Abstract: Aiming at the plastic shrinkage cracking of cement mortar, the constitutive equations of it in laboratory were established by testing plastic tensile strength, plastic capillary shrinkage stress and water loss evaporation rate of mortar under different composition parameters, environmental parameters, initial structural parameters and constraints condition parameters. And the early warning system of it was explored. The results showed that the seven-element constitutive equation of plain mortar and the nine-element constitutive equation of mortar with polyvinyl alcohol (PVA) fiber can effectively predict the plastic shrinkage cracking state of mortar outdoors. An early warning system for it was initially established.

Abstract: At present, the commonly used cement has low tensile strength and low flexural strength, which is a fatal defect of cement materials. It is extremely urgent to conduct research on this shortcoming of cement. In addition, the steel industry steel mill produces a large amount of waste steel slag. The chemical composition of steel slag is similar to that of cement. This experiment makes full use of waste steel slag as raw material to prepare cement to improve the performance of cement materials. Using limestone, sandstone, shale, steel slag and river sand as the main raw materials, through the powder preparation, mixing, calcination, grinding, molding process and performance analysis of raw materials. After the calcination, the cement clinker in the form of a block becomes higher in hardness as the steel slag is incorporated. The higher the calcination temperature, the smaller the steel slag incorporation maximum. When the calcined at 1150 °C is mixed with 17.5% steel slag, a cement with better performance can be obtained.

Abstract: This paper presents the compression and consolidation behaviors of clay supported by soil-cement column. A series of consolidation tests was performed on kaolin samples supported by soil-cement column with the ratio between diameters of column and soil sample () ranging from 0 to 0.4. All samples with soil-cement column were cured for 28 days under the vertical pressure of 25 kPa. The sample preparation techniques simulating dry deep soil mixing method was developed. The test results showed the elastic region expanded with increasing value of . However, there was no effect of on deformation behavior in the elasto-plastic region. Moreover, the value of was considered constant over the range of testing stress level, for the value of of 0 and 0.2. For the value of of 0.3 and 0.4, the values of in the elastic region was greater than that in elasto-plastic region.