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To meet the requirement of machine-made sand application in concrete structures, it is necessary to understand the bond properties of steel bar with machine-made sand concrete (MSC). Therefore, the experimental studies were carried out on the bond of plain steel bar with MSC by the central pull-out test method. Three specimens were cast as one group, 6 groups were tested considering the changes of strength grade of MSC and ordinary concrete. The bond-slip curves were measured and analyzed. The results show that the bond slip begins at the tensile side and transfers gradually to the free end before the entire slip turns up along the interface of plain steel bar and surrounded concrete, the largest average bond stress, i. e. the bond strength of plain steel bar corresponds to the initial entire slip of plain steel bar. With the increasing strength grade of MSC and ordinary concrete, the difference of slip at tensile side and free end becomes greater. Comparing that only appears in ordinary concrete with higher strength, the larger slips turn up while the bond stress reaches the largest for the plain steel bar in MSC. Larger scatter of bond strength is between specimens in the same group. Some plain steel bars yields with the beginning of entire slip along the interface.

Tests were carried out to study the durability of fine aggregate concrete and composite concrete simultaneously provided by the wet-sieving technique for the thermal insulation composite wall as building envelops. The workability of every concrete satisfied the basic requirement of cast quality. The composition analyses of concrete showed that compared with the ordinary concrete, the volume percent of coarse aggregate was increased and the volume percent of cement mortar was decreased due to that the residual coarse aggregate stayed on the sieve was blended with ordinary concrete, which increased the resistances of composite concrete to chloride penetration, water penetration and carbonization. Meanwhile, the resistances of fine aggregate concrete to chloride penetration, water penetration and carbonization were reduced due to the obvious increase of the volume percent of cement mortar.

A large impaired reinforced concrete beam with cracks was strengthened under self-weight action by the externally bonded steel frame composed with bottom steel plate and side hoop steel belts. The normal service loading behaviors of this beam were tested to verify the effectiveness of this strengthening method specified in current Chinese design code. Based on the analyses of test results, it can be concluded that: the deformation of flexural cross section of this beam fitted the assumption of plain cross section, the steel plate could effectively enhance the flexural stiffness and decrease the deflection of this beam, no new cracks appeared under the normal service loads, the cracks at bottom of this beam were more confined by the steel frame than those at web zone. Therefore, other measure should be taken to avoid the opening of web cracks.

Combined with the typical prestressed concrete continuous-beam bridge with 17m+28m+17m span over the main channel of the Central Line of South-to-north Water Transfer Project, two finite element models of this bridge, one considering and another without considering the pile-soil action, were built by the specialist bridge analysis software MIDAS/Civil 2011. The main vibration mode and its frequency were calculated by the self-vibration analysis, and the seismic response of the bridge was given out by the SRSS method of response spectrum method. Based on the calculations, the effect of pile-soil action on the dynamic characteristics and seismic behaviors of the bridge was studied. The results show that the pile-soil action brought the bridge structure into flexible, which led to the smaller vibration frequency but had no influence on the top two vibration modes. It also led to the larger displacement at top of piers and midspan of continuous-beam and the smaller internal forces of brake pear under the seismic action.

The paper introduces the experiments of sulfate attack on concrete under stress state. The concrete (MSFAC) was made with machine-made sand and fly ash. Before immersed in sodium solution with sulfate-ion concentration of 50000mg/L, the concrete beams with 100mm×100mm ×400mm dimension were in flexural tensile stress at levels of 20%, 40% and 60% of flexural tensile strength by the special designed stress devices. The sulfate-ion content in different erosion depths of concrete was measured at attack age of 30, 90, 180, 270, 360, 540 and 720 days by the chemical titration method. The results show that the apparent damage such as rough surface and cement past peeling off became more serious with the increasing tensile stress level and the prolongation of attack age, while much more obvious crystallization of gypsum was in surface cracks, the sulfate-ion content in the first layer near surface did not reflect the real status of concrete affected by tensile stress levels. The sulfate-ion contents of inside layers increased basically with the attack age at stress levels lower than 60% of tensile strength of concrete. In conditions of the experiment, the sulfate-ion content reduced when the attack age was longer than 540 days at the stress level of 60%.

The wavelet and EMD method are taken in order to accurately extract the fault information from the audio signal with a lot of noise. The bearings were studied for the object. This paper proposed a method based on wavelet and EMD frequency characteristics of the acoustic signal information extraction, and the method used in bearing fault feature extraction. The experimental results show that: the method can effectively extract the fault characteristic frequency of bearing.

Three-dimensional digital model of hot rolling-mill housing was built. The natural frequency and vibration mode shape of the first 10 order modes of hot rolling mill housing were calculated using ANSYS software. The vibration mode shape was studied in detail. The striking vibration signal and subsequently the natural frequencies were measured by placing two 3-Dimensional accelerators in the key points of the rolling mill horsing. Theoretical calculations and experimental results verified each other，high agreement was shown between the experimental results and the theoretical results. The first 10 mode frequency all appeared in the experiment signal with low error. The main mode frequency (117.3Hz) of the experimental signal has the lowest error down to 0.07%.

Tests were carried out to study the concrete attacked by magnesium sulfate solution. The concrete specimens were exposed in the magnesium sulfate solution with three different concentrations for 360 days. At the exposure times of 90 days, 180 days, 270 days and 360 days, the properties of concrete such as the mass change, the compressive strength and the tensile strength were measured, and the contents of sulfate-ion diffusing into different depths of concrete were determined. Their changes with the solution concentration and the exposure time are analyzed in this paper, which could be used as reference for the protecting of concrete against the attack of magnesium sulfate.

Combined with the design of a bridge with prestressed concrete continuous box-girder, and in accordance with the Chinese guidelines of seismic design for highway bridge, the numerical models with and without considering the pile-soil action were built using Midas Civil software. The response spectrum method was used to analyze the seismic response of the bridge under E1 and E2 seismic actions. The vibration characteristics such as frequency, period and mode as well as the internal forces and displacements of piers are discussed in view of the effect of the pile-soil action.

This paper introduces the design of a small-size single-pylon cable-stayed bridge to be built in Xingtai city, China. The main structural members of this bridge including box-girder, stayed cables and pylon were selected to meet the requirement of bearing properties and artistic display. The numerical model for analyzing the static properties of the bridge structure was made by the design software MIDAS/Civil. The distribution and ultimate value of internal forces, stress and displacement of these main members are summarized, which provide the basis for calculating the reinforcement and prestressed strands of the bridge.

A lumped mass model with two degrees of freedom for the vertical vibration system of four roller hot strip rolling mill stand is proposed, and then the parameters of dynamic model , include the equivalent mass , equivalent stiffness and its natural frequencies, were calculated by MATLAB package. The correctness of the model is verified via field vibration testing and signal analysis in the strip rolling process. Comparative the six degrees freedom model, the two degrees freedom model of our proposed is simplified reasonability and the model accuracy is maintained certainly . The two degrees freedom model is critical for the research of digital simulation of the strip rolling process. The research result have important theoretical and practical significance for the parameter optimization of the AGC system , vertical vibration control, the product quality improvement and the rolling speed increase for the rolling mill system.

Combined with the practical design of a prestressed concrete continuous box-girder bridge with changed sections, the effect of side-web slope on the loading properties of this bridge was analyzed. The numerical modes of this bridge were built using the specialist FEM software, 5 side-web slopes were considered by changing the width of box floor. The results show that the changes of side-web slope influence the mid-span deflection of box-girder in a small range under vehicle load, but affect obviously on the transversal loading properties such as crack width and flexural resistance of the box roof. Based on this, the suitable side-web slope is selected. It may be referenced by the similar design of this kind of bridges.

Fly ash (FA) is always used as the pulverized admixture of concrete with machine-made sand to improve the bad workability of fresh concrete such as lower flowing and serious bleeding. According to the specification of Chinese standard, there are three ways of admixing FA into concrete including the additional admixing, the equal-mass replacing cement and the over-mass replacing cement. This paper researches the possibility for unifying these three ways in the mix proportion design of concrete with machine-made sand by fitting the test data with the formula of water to cement ratio. The regression coefficients are given out corresponding to these three ways, the influences of FA on concrete are discussed. The issues in current mix proportion design methods are pointed out. To efficiently play the function of FA as the beneficial admixture of concrete, the activity of FA should be considered as a key factor in the mix proportion design of concrete.

Due to many different characteristics such as irregular polygon particle with pointed edges, rough surface and larger content of stone powder, machine-made sand has ignorable effects on the properties of concrete. As the basis for the design of concrete structures, the relations among the basic mechanical properties of concrete such as compressive strength, tensile strength, flexural strength and elastic modulus should be clearly understood. This paper summarizes the test data from the published references, and discusses the relations among these properties by statistical analyses compared with those of ordinary concrete. The results show that the axial compressive strength and the tensile strength can be prospected by the same formulas of ordinary concrete specified in current Chinese design code, but the prospected tensile strength should multiply a reducing coefficient when the strength grade of concrete is lower than C30. The elastic modulus of concrete with machine-made sand is larger than that of ordinary concrete, which should be prospect by the formula in this paper. Meanwhile, the formula of flexural strength is suggested.

Experiments were conducted to study the mechanical properties and water permeability of recycled aggregate porous concrete. The orthogonal test was designed considering four parameters including water to cement ratio, cement content, grain series of recycled aggregate and aggregate to cement ratio, each parameter was set at three levels. Performances of porous concrete were measured such as cubic compressive strength, flexural strength, continuous porosity and water penetration coefficient. Test results are analyzed on the basis of orthogonal test method, the optimum proportions corresponding to every test parameters are given out. The ranges of every test parameters are also proposed. It provides a reference for constructing porous concrete roads by recycled aggregate made of old concrete from dismantled buildings.

A lumped mass model with six degrees of freedom for the vertical vibration of four roller hot strip rolling mill stand was proposed, while its natural frequencies were calculated by MATLAB software. The numerical calculation results were proved more accurate through field vibration test. This vertical vibration model can be applied for dynamic simulation and structural dynamic modification with important theoretical and practical significance in mastering the vibration characteristics of four-roll mill, avoiding vertical self-excited vibration and improving production efficiency.

Experiments were conducted to study fly ash concrete (FAC) attacked by sulphuric acid. The cubes with dimensions of 100 mm were cast and immersed in sulphuric acid solution with different pH values of 2, 3 and 4, and tested at exposure times of 28 d, 56 d, 90 d, 150 d and 365 d respectively. The compressive strengths of concrete were tested, and the SO42- contents of concrete at different depths were measured with powder samples by the chemical titration method. The results show that FAC has certain ability to resist corrosion of sulphuric acid though exposed surfaces were damaged at long-term exposure times, the concrete strength at same exposure time decreases with the increasing density of sulphuric acid solution, the SO42- mainly contains in shallow layer of concrete while the content decreases obviously with the increasing depth of concrete. With the increasing density of sulphuric acid solution, phenomena of surface cement paste peeling off surface of concrete and crystal CaSO4 separated out of concrete became seriously. The deterioration mechanisms of FAC attacked by sulphuric acid are discussed.

Experiments were carried out to investigate the dry-shrinkage of masonry mortar affected by mass content of polypropylene fiber. The results show that proper content of polypropylene fiber is helpful to effectively reduce dry-shrinkage of mortar especially in early age, the reduction relates to water to cement ratio of mortar. Meanwhile, the relationships of water to cement ratio and content of polypropylene fiber in affecting dry-shrinkage of masonry mortar are analyzed, which can be as reference for selecting such optimum values as water to cement ratio and content of polypropylene fiber in practices.

Experiments were carried out to investigate such basic properties as workability and strength of masonry cement mortar affected by mass content of polypropylene fiber. The results show that proper mass content of polypropylene fiber is helpful for effectively adjusting consistency and layering to bring better workability of fresh mortar, the relative higher bending strength of mortar can be got by admixing reasonable mass content of polypropylene fiber while slight improved compressive strength reaches. The relationships of water to cement ratio and mass content of polypropylene fiber in affecting these basic properties of masonry mortar are analyzed, which can be as reference for selecting optimum water to binder ratio and mass content of polypropylene fiber in practices.

Experiments were carried out to study such basic properties as workability and strength of masonry cement mortar affected by mass content of cement equally replaced by stone powder. The mortar was designed in strength grade of M20 with three kinds of mix proportions, three replacing ratios of cement by stone powder. The results show that part of cement equally replaced by stone powder irregularly influences consistency and layering of fresh mortar but still brings fresh mortar into better workability; the optimum mass content of cement equally replaced by stone powder relates to the water to binder ratio of mortar, which are 5 %, 10 % and 15 % successively corresponding with 1.0, 0.9 and 0.8 water to binder ratio. Comprehensively concerned about the ratio of bending to compressive strengths of mortar, the referenced mix proportions of mortar with stone powder are proposed for application in practices.

The behaviors of linkage of built-in insulation reinforced concrete composite wall subjected to gravity load were experimental studied in this paper. The gravity load was computed as the sum of self-weights of thermal insulation layer, external concrete cover and surface decoration materials. Steel tube with square section was designed as the linkage. Two specimens modeling practical RCCW were cast and tested in Lab, many rectangular steel plates were used to simulated the uniformly distributed load on surface of external concrete cover. The relative displacement between inside structural reinforced concrete wall and external concrete cover, the strains of surface concrete and steel tube walls were measured. Tests were finished when load was over 3.24 times of design value, no relative displacement and only smaller concrete strains were observed, maximum tensile and compressive stresses of steel tube walls were only 6.3 % of design strength. It is concluded that the linkages are safe and the entirety of RCCW is good enough to satisfy the design requirements.

Based on a series tests, the properties of proto-machine-made sand of gravel such as grain feature, fineness modulus, grading, density, void ratio and MB value as well as the fineness distribution of stone powder were studied, the influences of content of stone powder on these properties of sand and strength of cement mortar were investigated. The results are introduced in the paper, some of them contribute to explain the special properties of concrete mixed with proto- machine-made sand.

Experiments were conducted to study the workability of fresh concrete and basic mechanical properties of hardened concrete with gravel-crushed proto-machine-made sand. Effects of water to cement ratio and content of stone powder were mainly considered. Based on the test and before, the values of practical parameters in formula are obtained for calculating mixed strength of concrete, and the beneficial range of water to cement ratio is proposed. Meanwhile, the reasonable water content, sand ratio and content of stone powder are also suggested.

The behaviors of linkage of built-in insulation reinforced concrete composite wall subjected to wind load were experimental studied in this paper. Three specimens modeling practical RCCW were cast and tested under static and repeated loads. The relative displacement between inside structural reinforced concrete wall and external concrete cover, the strains of steel tube walls were measured. The results show that specimens damaged with cracks at interface between external concrete cover and thermal insulation layer when load was up to 11.3 times of design value, the maximum stress of steel tube walls reached 25.3 % design strength, the safety factor is 1.67 when concrete cracked at steel tube. Therefore, the linkages are reliable to bear wind load on external concrete cover.

The mechanical properties of concrete mixed with composite coarse-aggregate were studied by the orthogonal test method, in which the four factors such as the cement content, the percent of cement replaced by fly ash, the percent of crushed limestone with grain size of 16-25 mm replaced by lightweight aggregate with the same grain size and the water to binder (cement + fly ash) ratio were considered. The results show that the water to binder ratio is the most effective factor influencing all of the mechanical properties, the mechanical properties except the splitting tensile strength are less influenced by the cement content, the elastic modulus and axial compressive strength as well as flexural tensile strength is largely affected by the replacement of cement by fly ash. The effect of the replacement of crushed limestone by lightweight aggregate is much more obvious on the cubic compressive strength than on the axial compressive strength, and larger on the flexural tensile strength than the splitting tensile strength.

To improve the application of the new proto-machine-made sand in structural engineering, tests are carried out to study the drying shrinkage of concrete affected by stone powder in proto- machine-made sand. The target cubic compressive strength of concrete is 55 MPa, the main factor varied in mix proportion of concrete is the contents of stone powder by mass of proto-machine-made sand from 3 % to 16 %. The drying shrinkage strains of concrete are measured by the standard method at the ages of 1 d, 3 d, 7 d, 14 d, 28 d, 60 d, 90 d, 120 d, 150 d and 180 d. Based on test results, the drying shrinkage of concrete affected by the contents of stone powder in proto-machine-made sand is analyzed and compared with that of similar test of concrete with traditional machine-made sand, which shows that there is the optimum content of stone powder resulting in the lower drying shrinkage of concrete. The formula for predicting drying shrinkage strain of concrete is proposed.

The new reinforced concrete composite wall (RCCW) with inner insulating layer of polystyrene panel was developed to improve the durability of external thermal insulation plate on walls. The composite structure and construction method of the RCCW is briefly introduced in this paper. The thermal insulation behaviors such as conduct heat coefficient and total heat resistance of RCCW are tested by the protection chest method, the measured and calculated results of thermal insulation properties of the RCCW are compared with each other, the effect of heat-bridge resulted from connected concrete supports of specimen and bottom side concrete of specimen covering inner insulating layer on the test results is discussed.

La1.6Ln0.4Zr2O7 (Ln= La, Nd, Dy, Er) nanocrystals were prepared by stearic acid combustion method. The samples were characterized by powder X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) nitrogen adsorption, transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The photocatalytic activity of La1.6Ln0.4Zr2O7 was evaluated by the photocatalytic degradation of methyl orange. The order of the photocatalytic activity was as following: La1.6Er0.4Zr2O7>La1.6Dy0.4Zr2O7> La1.6Nd0.4Zr2O7> La2Zr2O7. La1.6Dy0.4Zr2O7 showed that the best photocatalytic activity and the reason may be related to the big magnetic moment of Er3+. It may be considered largely to be caused by the partly occupied Ln4f levels. Since the solid samples have the same structure, the reason that La1.6Er0.4Zr2O7 shows the highest reactivity may be related to lowest Ln4f level of Er3+.