Abstract:Polypropylene(PP) fiber was modified by acrylic acid grafted on its surface by suspension in water medium.The effect of modified PP fiber on mechanical properties of cement mortar was studied.The surface microstructure and active functional group of modified PP fiber,the fracture profile of cement mortar samples were analyzed by SEM and IR.The results show that acrylic acid is grafted on the surface of PP fiber after modification.Comparing with cement mortar reinforced by ordinary PP fiber,the flexural stre...

Abstract:The effects of fly ash,ground granulated blast-furnace slag and water-binder ratio(m_w/m_b) on the hydration heat and the hydration exothermic process of paste in ultra high strength concrete at low m_w/m_b were investigated by the test system of hydration heat.According to the experimental results,the hydration exothermic process of paste,with the replacement level of 10% fly ash or slag,is similar to that of the control.However,with the increasing addition of fly ash or slag to 30% or more,the highest hyd...

Abstract:The effects of vinyl redispersible polymer(VRP) on the hydration products of cement pastes within hydration time of 72 h were investigated through step scanning X-ray diffraction(XRD),()~(29)Si nuclear magnetic resonance(NMR) and environmental scanning electron microscopy(ESEM) techniques.The results show that VRP postpones the formation time of crystalline ettringite(AFt),calcium hydroxide(Ca(OH)_2) and calcium silicate hydrate(C-S-H) gel of cement pastes,and decreases the content of these three hydration ...

Abstract:Hydration curves of cements with varied superplasticizer were measured by isothermal calorimetry(TAM-AIR).Three heat release curves were analyzed by Db10.Cement hydration curve with new-type superplasticizer of polycarboxylic acid(SPC) lags behind that of cement adding naphthalene sulphonate formaldehyde(NSF) condensates and the control sample 171.3 min and 235.9 min respectively.Decomposition and reconstruction showed the approximation signal energy and the error of reconstruction signal and original signa...

Abstract:Tests were conducted to investigate the properties of steel-fiber reinforced high-strength concrete(SFRHSC) containing large coarse aggregate in continuous gradation with maximum size of 25 mm and(31.5 mm) respectively.The mixture slump,the cubic and axial compressive strength,the splitting-tensile and flexural-tensile strength of SFRHSC are analyzed considering the factors of the maximum size of coarse aggregate,the water to cement ratio,the length and the volume fraction of steel fiber.The test results ar...

Abstract:The application of phase change material(PCM) in floor radiation heating system was studied.The composite granule PCM were prepared by sol-gel method and the PCM gypsum mortar was prepared by using the composite granule PCM.Based on the floor heating experiment platform,floor heating experiments was performed by using PCM mortar and common mortar separately to obtain the characteristic of charging and discharging latent heat energy of the containing PCM floor and to analyze the indoor temperature distributi...

Abstract:The radar cross section(RSC) of samples was tested in a microwave anechoic chamber.Influences of porous structure on electromagnetic wave absorption properties of porous concrete were investigated,and influences of porosities, types of aggregate and aggregate size on electromagnetic wave absorption properties of porous concrete were studied.The results show that porous concrete exhibites perfect wave absorption properties.Types of aggregate nearly have no effect on wave absorption properties.For porous conc...

Abstract:Mechanical properties of corroded prestressed tendons were considered for the durability evaluation of prestressed concrete structures.It was verified that the stress has limited effect on corrosion rate of steel wire by corrosion tests for steel wires under high tensile stress and the effect may be neglected in the accelerated corrosion test.Prestressed tendons were placed in concrete and corroded by direct current to them.Through tensile tests,the mechanical behaviors of these corroded tendons were studie...

Abstract:Based on pull-out test of 16 specimens without stirrups,the bond behavior of ribbed bar and strand were investigated.Test results show that in the same bond medium,the bond strength of single ribbed bar is higher than that of single strand,however,the maximum slip value of the former is far less than that of the latter.No matter the reinforcement is single ribbed bar or single strand,the bond strength and maximum slip value between reinforcement and concrete are greater than those between reinforcement and ...

Abstract:Excessive permeability are responsible mainly for early damage of asphalt pavement,quantitative analysis was made to elucidate the rule of influence of various factors on permeability of asphalt mixture.The results show that air void,types and gradations of mixture,nominal maximum aggregate size(NMAS) and thickness of mixture have important influence on permeability.The bigger NMAS and the air void,the more coarse gradation and thinner structure mean the bigger permeable possibility for asphalt mixtures.Com...

Abstract:The influence of loading rate on the mechanical properties of two typical cement asphalt mortars(CAMs) with varied asphalt to cement ratio(m_A/m_C) was studied.Uniaxial compressive stress-strain curves of the two CAMs were tested by the MTS(material testing system) at different displacement rates ranging from 0.3 mm/min to 30.0 mm/min.The correlation between peak strength or elastic modulus and loading rate was acquired and experimental data were fitted to the presumed mathematical formula that is proven ap...

Abstract:The purpose of this study was to investigate and verify the theoretical fatigue limit for SBS modified asphalt mixtures.To investigate this,the flexural beam fatigue test was used to test an asphalt mixture under different tensile strain levels.Varying the tensile strain levels allowed the simulation of a range of pavement thicknesses,from thin pavements(high tensile strain levels) to thick pavements(low tensile strain levels).The results show that there is a finite fatigue life for the asphalt mixtures und...

Abstract:Micro structural model of foamed asphalt with foaming agent was proposed to analyze the mechanism of foaming agent in asphalt foaming.For improving asphalt foaming and increasing the cold recycling foamed asphalt mixture water stability,3 types of foaming agent(A,B,C) were chosen for asphalt foaming and mixture indirect tensile strength test.Results indicate that foaming agent A(Redicote C-450) has relatively small influence on expansion ratio,and little influence on half life;foaming agent B(cetyl trimethy...

Abstract:According to the demands of on-site construction conditions and construction technology of continuous pumping lift-up for steel pipe arch bridge,property requirements and suitable evaluation methods of self-compacting concrete(SCC) filled with steel pipe arch were proposed.By using the preparation techniques including optimization of basic parameters of concrete mix proportion,admixture composition and mineral admixture addition,self-compacting concrete filled with steel pipe arch was prepared with the prop...

Abstract:Pre-cast reinforced concrete component products with designed strength of 40 MPa were prepared with calcium containing expansive agent,blast furnace cement B and low absorption recycled aggregate as one of effective methods to use recycled aggregate.It is concluded that recycled concrete exhibits almost the same performance on strength and durability compared with common concrete,which meets all requirements set forth in standard of JASS 10,and it is feasible for recycled aggregate to be used in the pre-cas...

Abstract:Based on the experimental research on the activity,physical properties,mechanical properties and durability of coal gangue,fifteen groups of mixture with different mixing ratio was designed for the research of technical feasibility of the lime-fly ash stabilized coal gangue mixture used as base course of road in seasonal frozen area.The unconfined compressive strength of the mixture under the condition of water saturation was determined.The results show that the unconfined compressive strength of lime-fly a...

Abstract:The influence of limestone powder on the hydration characteristic of complex binder was studied by using mercury intrusion porosimetry(MIP),scanning electron microscopy(SEM) and X-ray diffraction(XRD) techniques.Testing results show that similar to fly ash,limestone powder will decrease the water requirement of complex binder.The strength of mortar will be decreased on the addition of limestone,however,the effect of decrease will become less at later period.Limestone powder and fly ash will also decrease th...

Abstract:The electric flux of high-performance concrete(HPC) with fly ash,blast furnace slag and silica fume and normal concrete(NC) were tested by using ASTM C1202,the diffusion coefficient and threshold value of chloride for the corrosion of steel bar were analyzed and calculated.Accordingly the service life of the HPC and NC was evaluated for the first time by the boundary element method(BEM).The result shows that the theory of computing length and the model of BEM for chloride diffusion is suitable for predictio...

Abstract:Aiming at the problem that influences the lime dosage on the strength of the cement-lime-fly ash,the cement-lime-fly ash stiff system was researched by simple-lattice designing and influences of lime on the different age's strengths were discussed.It is proved that there is a relationship between the influence rules of lime on the early strength of this system and cement content,the lime has feeble active effect on early strength of system when the content of cement is below to 7%(by mass) and that lime has...

Abstract:Natural pumice from the eastern Inner Mongolia was used as coarse aggregate for lightweight aggregate concrete.Through rapid freeze-thaw cycle experiment on lightweight aggregate concrete samples in an open system,the factors influencing heaving of the fiber reinforced concrete material were investigated and the characteristics of temperature change during freeze-thaw and the factors influencing heaving change of fiber reinforced concrete was analyzed.The freeze-thaw property subject to sudden temperature d...

Abstract:Taken advantages of the characteristics of super-elasticity and restoring forces while the shape memory alloy(SMA) was excited,concrete model beams were established by embedding different pre-stretching length,different pieces of Ni-Ti SMA under martensitic state into the concrete tensile zone before the concrete casted under environmental temperature,the relationship between the resistance rate of SMA and the cracks width of beams was studied under loaded process.The impact of slip and bond between the con...

Abstract:In order to improve the combination ability of the expanded polystyrene(EPS) beads and the cement mortar in the EPS lightweight concrete,and the mechanical properties of this concrete,the ethylene-vinyl acetate copolymer(EVA) emulsion was used to modify the EPS surface.Mechanical properties of EPS lightweight concrete were tested;the influence of EVA on EPS lightweight concrete had been analyzed by means of scanning electron microscope(SEM),X-ray diffraction and infrared spectroscopy spectrum.Tests results ...

Abstract:Through finite element model to simulate the overlay materials and structure,a reasonable overlay materials and structure were calculated and analyzed based on the analyses of fatigue tests of resistance of the asphalt overlay to reflective cracking at home and abroad in the lierature.A method for improving general rut instrument was put forward by using reciprocating loading mode of rutting wheel to simulate forming process of reflective cracking(flexural-tensile type and shear type) caused by load.A test ...

Abstract:Thermally induced switching temperature,spectral transmittance of thermotropic materials manufactured by a different mixing proportion of hydroxypropyl methyl cellulose(HPMC),sodium chloride and pure water was measured.Switching speed from transparent state to light scattering state of thermotropic layer in double glazing window was analyzed with numerical simulation.Radiation transmittance was tested on sample of thermotropic double glazing window,double glazing window and low-E double glazing window.Resul...

Abstract:Na_2O-CaO-SiO_2 opaque glass containing fluoride and phosphate as opacifer was prepared by melting method and the effect of the composite opacifers on the transmission,crystalline phases,glass characteristics and mechanical properties of Na_2O-CaO-SiO_2 glass were studied by using UV-Vis,DTA,XRD and SEM technologies.The results show that with the addition of fluoride and phosphate,Na_2O-CaO-SiO_2 glass crystallizes irregular grain to opalize glass.The opaque glass containing fluoride and phosphide appears o...

Abstract:In order to improve the anti-erosion performance of cement-stabilized macadam base material,polypropylene fiber reinforced cement-stabilized macadam base material was made to investigate the effects of fiber content, fiber length,cement content,curing age and eroding time on its anti-erosion property by MTS(material test system).The anti-erosion improvement mechanism of polypropylene fiber was analyzed from material composition,strength theory and fracture and damage theory.The test results show that the er...

Abstract:Volatile organic compounds(VOC) and formaldehyde emissions from interior wall coating were studied by measuring their concentration consecutively in an environmental testing chamber which was designed by ourselves according to USA standards.At the same time a fuzzy evaluation was built to evaluate the effect of pollutant from interior wall coating based on the experimental data and national standards.It has been shown that the pollutant emissions from interior wall coating can be presented as a rational dec...

Abstract:Mechanical pulp of wheat straw and bagasse was obtained by using technology of twisting up and high concentration refining.The product can partly replace the chemical pulp for wall decoration.The effect of addition of the mechanical pulp on appearance,stiffness,tensile,thermal insulation were investigated.It is shown that upon the increase of the addition of the mechanical pulp,the stiffness increases at first and then tends to decrease.It reaches peak to the increment to 9.36% and 8.62% at the addition of ...