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Comparative study on three dynamic modulus of elasticity and static modulus of elasticity for Lodgepole pine lumber 被引量:5
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作者 梁善庆 傅峰 《Journal of Forestry Research》 SCIE CAS CSCD 2007年第4期309-312,共4页
The dynamic and static modulus of elasticity (MOE) between bluestained and non-bluestained lumber of Lodgepole pine were tested and analyzed by using three methods of Non-destructive testing (NDT), Portable Ultras... The dynamic and static modulus of elasticity (MOE) between bluestained and non-bluestained lumber of Lodgepole pine were tested and analyzed by using three methods of Non-destructive testing (NDT), Portable Ultrasonic Non-destructive Digital Indicating Testing (Pundit), Metriguard and Fast Fourier Transform (FFT) and the normal bending method. Results showed that the dynamic and static MOE of bluestained wood were higher than those of non-bluestained wood. The significant differences in dynamic MOE and static MOE were found between bulestained and non-bluestained wood, of which, the difference in each of three dynamic MOE (Ep. the ultrasonic wave modulus of elasticity, Ems, the stress wave modulus of elasticity and El, the longitudinal wave modulus of elasticity) between bulestained and non-bluestained wood arrived at the 0.01 significance level, whereas that in the static MOE at the 0.05 significance level. The differences in MOE between bulestained and non-bluestained wood were induced by the variation between sapwood and heartwood and the different densities of bulestained and non-bluestained wood. The correlation between dynamic MOE and static MOE was statistically significant at the 0.01 significance level. Although the dynamic MOE values of Ep, Em, Er were significantly different, there exists a close relationship between them (arriving at the 0.01 correlation level). Comparative analysis among the three techniques indicated that the accurateness of FFT was higher than that of Pundit and Metriguard. Effect of tree knots on MOE was also investigated. Result showed that the dynamic and static MOE gradually decreased with the increase of knot number, indicating that knot number had significant effect on MOE value. 展开更多
关键词 Lodgepole pine Non-destructive testing dynamic modulus of elasticity Static modulus of elasticity
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Dynamic Elastic Modulus of Cement Paste at Early Age based on Nondestructive Test and Multiscale Prediction Model 被引量:1
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作者 赵海涛 黄冬辉 +1 位作者 WANG Xiaojun CHEN Xudong 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2014年第2期321-328,共8页
This paper introduced a nondestructive testing method to evaluate the dynamic elastic modulus of cement paste. Moreover, the effect of water-cement ratio and conventional admixtures on the dynamic elastic modulus of c... This paper introduced a nondestructive testing method to evaluate the dynamic elastic modulus of cement paste. Moreover, the effect of water-cement ratio and conventional admixtures on the dynamic elastic modulus of cement paste was investigated, in which three kinds of admixtures were taken into account including viscosity modifying admixture (VMA), silica.fume (SF), and shrinkage-reducing admixture (SRA). The experimental results indicate that the dynamic elastic modulus of cement paste increases with decreasing water-cement ratio. The addition of SF increases the dynamic elastic modulus, however, the overdosage of VMA causes its reduction. SRA reduces the dynamic elastic modulus at early age without affecting it in later period. Finally, a multiscale micromechanics approach coupled with a hydration model CEMHYD3D and percolation theory is utilized to predict the elastic modulus of cement paste, and the predictive results by the model are in accordance with the experimental data. 展开更多
关键词 dynamic elastic modulus nondestructive test viscosity modifying admixture silica fume shrinkage-reducing admixture multiscale model
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Low embankment dynamic response under vehicle traffic loads in arid-oasis areas
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作者 WAN Qi YANG Xiao-hua +1 位作者 YIN Pei-jie BAO Han 《Journal of Mountain Science》 SCIE CSCD 2020年第7期1776-1789,共14页
The use of low embankments is of significant concern for ecological protection in aridoasis areas.Based on the project of Sansha Expressway located in Kashgar City,Xinjiang,China,physical model tests were conducted in... The use of low embankments is of significant concern for ecological protection in aridoasis areas.Based on the project of Sansha Expressway located in Kashgar City,Xinjiang,China,physical model tests were conducted in this study to investigate the dynamic response of the low embankment as per the effects of road structure,load amplitude,load frequency,load cycle,and moisture content.The dynamic stress is shown to increase with load amplitude while the dynamic elastic modulus decreases with load amplitude under short-term loading.The load frequency slightly influences the soil’s dynamic behavior;higher frequencies can improve the dynamic elastic modulus of the subgrade soil.The moisture content has greater influence on the mechanical properties of the subsoil than that of subgrade layer.The subgrade bears the majority of the traffic load as the stress dissipates to 37%of the whole value on its surface.The number of load cycles has the greatest effect on the dynamic response among the influencing factors tested.The dynamic elastic modulus with the type of long-term dynamic loading is only 40%-52%of that with static loading across the entire depth range.The dynamic stress shows significant accumulation with load cycles over the long-term dynamic loading test and becomes stable after 8×10~4 cycles of loading.An equation is established to quantify the cumulative dynamic stress in the low embankment under long-term dynamic loading conditions. 展开更多
关键词 Low embankment dynamic response Model test Moisture content dynamic elastic modulus Cumulative dynamic stress
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Detection of Frost-Resistance Property of Large-Size Concrete Based on Impact-Echo Method
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作者 Qi Feng Zhengyue Ren Dan Wang 《Structural Durability & Health Monitoring》 EI 2023年第1期71-88,共18页
The dynamic elasticity modulus(Ed)is the most commonly used indexes for nondestructive testing to represent the internal damage of hydraulic concrete.Samples with a specific size is required when the transverse resona... The dynamic elasticity modulus(Ed)is the most commonly used indexes for nondestructive testing to represent the internal damage of hydraulic concrete.Samples with a specific size is required when the transverse resonance method was used to detect the Ed,resulting in a limitation for field tests.The impact-echo method can make up defects of traditional detection methods for frost-resistance testing,such as the evaluation via the loss of mass or strength.The feasibility of the impact-echo method to obtain the relative Ed is explored to detect the frost-resistance property of large-volume hydraulic concretes on site.Results show that the impact-echo method can replace the traditional resonance frequency method to evaluate the frost resistance of concrete,and has advantages of high accuracy,easy to operate,and not affecting by the aggregate size and size effect of samples.The dynamic elastic modulus of concrete detected by the impact-echo method has little difference with that obtained by the traditional resonance method.The one-dimensional elastic wave velocity of concrete has a good linear correlation with the transverse resonance frequency.The freeze-thaw damage occurred from the surface to the inner layer,and the surface is expected to be the most vulnerable part for the freeze-thaw damage.It is expected to monitor and track the degradation of the frost resistance of an actual structure by frequently detecting the P-wave velocity on site,which avoids coring again. 展开更多
关键词 Impact-echo method frost-resistance property dynamic elastic modulus ED elastic wave velocity transverse resonance frequency
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Assessment of flexural properties of different grade dimension lumber by ultrasonic technique 被引量:2
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作者 江京辉 吕建雄 +2 位作者 任海青 龙超 骆秀琴 《Journal of Forestry Research》 SCIE CAS CSCD 2007年第4期305-308,共4页
The dimension lumber (45mm×90mm×3700mm) of plantation Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) was graded to four different classes as SS, No. 1, No.2 and No.3, according to national lumber ... The dimension lumber (45mm×90mm×3700mm) of plantation Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) was graded to four different classes as SS, No. 1, No.2 and No.3, according to national lumber grades authority (NLGA) for structure light framing and structure joists and planks. The properties of apparent density was determined at 15% moisture content, bending strength and stiffness were tested according to American Society for Testing and Materials (ASTM) D198-99, and dynamic modulus of elasticity (Eusw) was measured by ultrasonic technique, for predicting the flexural properties of different grade lumbers. The results showed that Eosw was larger than the static MOE. The relationship between Eusw and static MOE was significant at 0.01 level, and the determination coefficients (R2) of the four grade lumbers followed the sequence as R^2No.2 (0.616)〉 R^2ss (0.567)〉 R^2No1 (0.366)〉 R^2No.3 (0.137). The R^2 of Fusw and MOR were lower than that of the Etru and MOR for each grade. The Eusw of all the grade lumbers, except No.3-grade, had significant correlation with the static MOE and MOR, thus the bending strengthof those grade lumbers can be estimated by the E The Etru valuesof four grade lumbers followed a sequence as No.2-grade (10.701 GPa) 〉 SS-grade (10.359 GPa) 〉 No.l-grade (9.840 GPa) 〉 No.3-grade (9.554 GPa). For the same grade dimension lumber, its Eusw value was larger than static MOE. Mean values of MOR for four grade lumbers follow a sequence as No.2-grade (48.67 MPa) 〉 SS-grade (48.16 MPa) 〉 No.3-grade (46.55 MPa) 〉 No. 1-grade (43.39MPa). 展开更多
关键词 Dimension lumber Lumber grade Ultrasonic technique dynamic modulus of elasticity Static modulus of elasticity modulus of rupture
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Effect of Li addition on mechanical properties and ageing precipitation behavior of extruded Al-3.0 Mg-0.5 Si alloy 被引量:3
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作者 YANG Xiao-kun XIONG Bai-qing +6 位作者 LI Xi-wu YAN Li-zhen LI Zhi-hui ZHANG Yong-an LI Ya-nan WEN Kai LIU Hong-wei 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第9期2636-2646,共11页
The effect of Li(2.0 wt%)addition on mechanical properties and ageing precipitation behavior of Al-3.0 Mg 0.5 Si was investigated by tensile test,dynamic elasticity modulus test,scanning electron microscopy(SEM),trans... The effect of Li(2.0 wt%)addition on mechanical properties and ageing precipitation behavior of Al-3.0 Mg 0.5 Si was investigated by tensile test,dynamic elasticity modulus test,scanning electron microscopy(SEM),transmission electron microscopy(TEM)and high-resolution transmission electron microscopy(HRTEM)images.The results show that the tensile strength of the Li-containing alloy can be significantly improved;however,the ductility is sharply decreased and the fracture mechanism changes from ductile fracture to intergranular fracture.The elasticity modulus of the Li-containing alloy increases by 11.6%compared with the base alloy.The microstructure observation shows that the Li addition can absolutely change the precipitation behavior of the base alloy,andδ′-Al_(3)Li phase becomes the main precipitates.Besides,β′′-Mg_(2)Si andδ′-Al_(3)Li dual phases precipitation can be visibly observed at 170℃ ageing for 100 h,although the quantity ofδ′-Al_(3)Li phase is more thanβ′′-Mg_(2)Si phase.The width of the precipitate-free zone(PFZ)of the Li-containing alloy is much wider at the over-ageing state than the base alloy,which has a negative impact on the ductile and results in the decrease of elongation. 展开更多
关键词 Al-3.0 Mg-0.5 Si alloy Li addition microstructure ageing behavior mechanical properties dynamic elasticity modulus
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Brine-freeze-thaw Durability and Crack Density Model of Concrete in Salt Lake Region 被引量:5
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作者 GONG Wei YU Hongfa +1 位作者 MA Haiyan HAN Wenliang 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2020年第3期561-570,共10页
The brine-freeze-thaw durability (defined as the durability under freeze-thaw cycles in Qinghai salt lake brine) of concrete (ordinary Portland cement concrete (OPC), high performance concrete (HPC-a), high performanc... The brine-freeze-thaw durability (defined as the durability under freeze-thaw cycles in Qinghai salt lake brine) of concrete (ordinary Portland cement concrete (OPC), high performance concrete (HPC-a), high performance concrete with steel fiber (HPC-b), and high performance concrete with high Young's modulus polyethylene fiber (HPC-c)) was systematically investigated by the relative dynamic elastic modulus, the relative mass, the appearance, the scanning electron microscopy, and the X-ray diffraction. In addition, the low-temperature physical and chemical corrosion mechanism and a crack density model after the modified relative dynamic elastic modulus being taken into consideration were proposed. The results show that the deterioration of OPC is the severest, followed by HPC-a, HPC-c and HPC-b. The admixture or the fiber is mixed into concrete, which can improve the brine-freeze-thaw durability of concrete. The critical mass growth of the failure of concrete is 3.7%. The cause of the deterioration of concrete under the brine-freeze-thaw cycles is physical and chemical corrosion, not freezing and thawing. The crack density model can effectively describe the deterioration evolution of concrete. 展开更多
关键词 brine-freeze-thaw durability relative dynamic elastic modulus relative mass micro-analysis modeling
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Evaluating Deterioration of Concrete by Sulfate Attack 被引量:3
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作者 龙广成 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2007年第3期572-576,共5页
Effects of factors such as water to cement ratio, fly ash and silica fume on the resistance of concrete to sulfate attack were investigated by dry-wet cycles and immersion method. The index of the resistance to sulfat... Effects of factors such as water to cement ratio, fly ash and silica fume on the resistance of concrete to sulfate attack were investigated by dry-wet cycles and immersion method. The index of the resistance to sulfate attack was used to evaluate the deterioration degree of concrete damaged by sulfate. The relationship between the resistance of concrete to sulfate attack and its permeability/porosity were analyzed as well as its responding mechanism. Results show that the depth of sulfate crystal attack from surface to inner of concrete can be reduced by decreasing w/c and addition of combining fly ash with silica fume. The variation of relative elastic modulus ratio and relative flexural strength ratio of various specimens before and after being subjected to sulfate attack was compared. 展开更多
关键词 sulfate attack STRENGTH relative dynamic elastic modulus PERMEABILITY CONCRETE
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Effect of carbonation-drying-wetting on durability of coral aggregate seawater concrete 被引量:2
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作者 Da Bo Yu Hongfa +3 位作者 Ma Haiyan Dou Xuemei Wu Zhangyu Chen Yan 《Journal of Southeast University(English Edition)》 EI CAS 2021年第1期67-74,共8页
Based on the drying-wetting cycles experiment and the carbonation-drying-wetting cycles experiment for coral aggregate seawater concrete(CASC)with different strength grades,the effects of carbonation-drying-wetting on... Based on the drying-wetting cycles experiment and the carbonation-drying-wetting cycles experiment for coral aggregate seawater concrete(CASC)with different strength grades,the effects of carbonation-drying-wetting on the durability of CASC are studied with the surface state,mass loss rate,relative dynamic elastic modulus,ultrasonic wave velocity and cube compressive strength as indices.Results show that the mass loss rate of CASC increases gradually with the increase in cycle times in the drying-wetting and carbonation-drying-wetting cycles.The mass loss rate increases relatively slowly at the initial stage but it increases remarkably after 10 cycles.The relative dynamic elastic modulus and ultrasonic wave velocity decrease gradually with the increase in cycle times.After 6 cycles,the decrease rate of the relative dynamic elastic modulus and ultrasonic wave velocity of CASC tends to be flat and the surface is slightly damaged.Compared with the initial 28 d cube compressive strength,the cube compressive strength of CASC decreases by 8.8%to 11.0%.Drying-wetting cycles and carbonation can accelerate seawater erosion on CASC,and drying-wetting cycles result in salting-out and accelerate the destruction of concrete.Therefore,the carbonation-drying-wetting accelerates the destruction of CASC. 展开更多
关键词 coral aggregate seawater concrete drying-wetting cycles carbonation-drying-wetting cycles mass loss rate relative dynamic elastic modulus ultrasound wave velocity
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Mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions 被引量:3
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作者 熊良宵 虞利军 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第3期1096-1103,共8页
To investigate the mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions, uniaxial compression test and ultrasonic test were performed. Test results show that the relative dynamic elas... To investigate the mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions, uniaxial compression test and ultrasonic test were performed. Test results show that the relative dynamic elastic modulus, the mass variation,and the compressive strength of cement mortar increase first, and then decrease with increasing erosion time in sodium sulfate and sodium chloride solutions. The relative dynamic elastic moduli and the compressive strengths of cement mortars with water/cement ratios of 0.55 and 0.65 in sodium sulfate solution are lower than those in sodium chloride solution with the same concentration at the420 th day of immersion. The compressive strength of cement mortar with water/cement ratio of 0.65 is more sensitive to strain rate than that with water/cement ratio of 0.55. In addition, the strain-rate sensitivity of compressive strength of cement mortar will increase under attacks of sodium sulfate or sodium chloride solution. 展开更多
关键词 cement mortar mechanical properties relative dynamic elastic modulus compressive strength
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Durability of Concrete with Different Improvement Measures and Its Ser-vice Life Prediction in Island and Reef Environment
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作者 GONG Wei YU Hong-fa +2 位作者 MA Hai-yan WANG Nan ZHU Hai-wei 《China Ocean Engineering》 SCIE EI CSCD 2022年第6期947-958,共12页
To solve the durability of island and reef concrete engineering in the harsh environment of high temperature,high salt,high humidity and windy,the strength grade of concrete and the type of corrosion inhibitor were us... To solve the durability of island and reef concrete engineering in the harsh environment of high temperature,high salt,high humidity and windy,the strength grade of concrete and the type of corrosion inhibitor were used as the influence factors,while the relative dynamic elastic modulus was used as the evaluation index.In addition,the law and time variability of the deterioration of concrete,the size effect,environmental similarity and the service life model were studied.The results showed that improving the strength grade of concrete could improve the durability of concrete,and corrosion inhibitor could slightly improve the durability of concrete.Time-varying law of the deterioration of concrete conformed to the univariate quadratic polynomial.Combined with the concrete damage equivalent theory,a size effect model based on the relative dynamic elastic modulus was proposed and verified,and the size effect coefficient was also given.An environmental similarity model between simulated and practical island and reef environment was proposed.Combined with the reliability theory and the first order second moment method,a new service life model of concrete structure was proposed.The authors were convinced that the research will be advantageous to researchers. 展开更多
关键词 island and reef environment relative dynamic elastic modulus size effect environmental similarity service life model
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Natural durability of wood of ten native species from northeastern Mexico
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作者 Artemio CARRILLO Rahim FOROUGHBACHK +2 位作者 Verónica BUSTAMANTE Christian WEHENKEL Humberto GONZáLEZ 《Forestry Studies in China》 CAS 2013年第2期160-166,共7页
Thorn scrub vegetation in Mexico is distributed over 50 million ha, where native tree species are the source of forage, timber, firewood and charcoal. Research describing wood durability of species from this vegetatio... Thorn scrub vegetation in Mexico is distributed over 50 million ha, where native tree species are the source of forage, timber, firewood and charcoal. Research describing wood durability of species from this vegetation type has not been fully determined, nor classified according to international standards. Thus, the aim of this study was to determine and classify the natural durability of ten woody species. Their natural durability was determined according to the European Pre-Norm 807, the loss of dynamic modulus of elasticity (MOEdyo) (MPa) was determined and wood mass loss (g) after being exposed to Trametes versicolor and Coniophora puteana fungi. Wood durability was classified accord- ing to the European Norm 350-1. Highly significant differences (p 〈 0.001) were found between the durability of woody species. The more durable species with lower MOEdyn lost were Condalia hooked (57.5% ± 0.6%), Havardia pallens (58.2% ± 0.4%) and Acacia schaffneri (58.9% ±6.3%). Species with lower mass loss after exposed to Coniophora puteana were Ebenopsis ebano (6.3% ±1.9%), Condalia hooked (8.6% ±2.3%) and Cordia boissieri (11.8% ±2.3%). E. ebano (7.1% ±2.4%), Condalia hooked (8.2% ± 2.5%) and Cordia boissieri (11.5% ± 3.1%) showed the lower mass lost after exposed to T. versicolor. According to European Norm 350-1, three woody species were classified as very durable and durable species. 展开更多
关键词 native species natural durability dynamic modulus of elasticity mass loss
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Freezing and Thawing Durability of Ultra High Strength Concrete
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作者 Jesus Muro-Villanueva Craig M. Newtson +2 位作者 Brad D. Weldon David V. Jauregui Srinivas Allena 《Journal of Civil Engineering and Architecture》 2013年第8期907-915,共9页
Resistance to freezing and thawing of two UHSC (ultra high strength concrete) mixtures was evaluated in accordance with ASTM C 666 Procedure A. The two mixtures (plain and fiber reinforced) were developed using ma... Resistance to freezing and thawing of two UHSC (ultra high strength concrete) mixtures was evaluated in accordance with ASTM C 666 Procedure A. The two mixtures (plain and fiber reinforced) were developed using materials local to southern New Mexico, USA. Three different curing regimens were investigated for the mixture with fibers and one curing regimen was studied for the mixture without fibers. All curing regimens included 24 h of ambient curing followed by four days of wet curing at 50 ℃, and then two days dry curing at 200 ℃. At an age of seven days, one batch of fiber reinforced specimens was air cured at ambient conditions for the following six days and then placed in a water bath at 4.4 ℃ for 24 h prior to initiating freezing and thawing cycles. The second batch was air cured from day seven to day 12, and then wet cured for one day at 23 ℃ prior to being placed in the 4.4 ℃ water bath. The final batch was wet cured at 23 ℃ from the seventh day to an age of 13 days and then placed in the 4.4 ℃ water bath. The mixture with no fibers was air cured from the seventh day to an age of 12 days and then wet cured for one day at 23 ℃ prior to being placed in the 4.4 ℃ water bath. Higher moisture levels during curing produced greater initial dynamic elastic modulus values and durability factors at the end of the freezing and thawing tests, with the greatest durability factor being 87.5. Steel fibers were observed to improve both compressive strength and durability factor for UHSC. 展开更多
关键词 Ultra high strength freezing and thawing DURABILITY dynamic elastic modulus quality factor.
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Experimental investigation on dynamic mechanical characteristics and microstructure of steam-cured concrete 被引量:5
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作者 LONG GuangCheng WANG Meng +1 位作者 XIE YouJun MA KunLin 《Science China(Technological Sciences)》 SCIE EI CAS 2014年第10期1902-1908,共7页
Steam-cured concrete is widely used to manufacture prefabricated units of high-speed railway foundation structure such as girder and track slab.The dynamic mechanical property of steam-cured concrete is one of the key... Steam-cured concrete is widely used to manufacture prefabricated units of high-speed railway foundation structure such as girder and track slab.The dynamic mechanical property of steam-cured concrete is one of the key properties affecting service performance of high-speed railway foundation structure.In the present paper,serial macro/micro-experiments were carried out to investigate the dynamic elastic modulus,shear modulus,damping ratio,and microstructure of steam-cured concrete.The relationships between compositions,curing regime,microstructure,and dynamic properties of steam-cured concrete as well as the corresponding mechanisms were discussed.The results indicate that steam-cured concrete in early age has a larger dynamic elastic modulus and shear modulus as well as a smaller damping ratio compared with standard-cured concrete.On the contrary,at a later age a slightly smaller dynamic elastic modulus and a larger damping ratio of steam-cured concrete are observed.Addition of mineral admixture results in a bit lower dynamic elastic modulus and damping ratio of concrete than that of the control specimen without mineral admixtures.The achievements can provide some fundamental suggestions for materials parameters selection during structural design of steam-cured concrete precast element. 展开更多
关键词 steam-cured concrete dynamic elastic modulus shear modulus damping ratio MICROSTRUCTURE
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Experimental Study on Mechanical Properties of Weathered Rock Covered by Loess 被引量:2
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作者 王平 吴志坚 +2 位作者 王峻 张泽忠 王谦 《Journal of Shanghai Jiaotong university(Science)》 EI 2013年第6期719-723,共5页
Based on dynamic triaxial test, the mechanical properties of the weathered rock covered by loess were studied. The cohesion value of weathered mudstone is far below that of the weathered sandstone, while the internal ... Based on dynamic triaxial test, the mechanical properties of the weathered rock covered by loess were studied. The cohesion value of weathered mudstone is far below that of the weathered sandstone, while the internal friction angle values are basically equivalent, about 30. Compared with the undisturbed sample, the cohesion value of remodeling weathered rock sample decreases significantly. With the increase of moisture content, the strength of weathered mudstone is obviously decreased due to the influence of the water softening efect. This results illustrate that the bearing stratum is not easily afected by external disturbance in comparison to weathered mudstone. In the engineering, in order to ensure the good mechanical properties of the soil, more attention should be paid to keeping the water content constant, even to reducing the water content. The experiments show that the relations between shear stress and strain of weathered rock were nonlinear and the behavior of weathered rock can be expressed by the hyperbolic model. The initial modulus of undisturbed weathered rock, under the same consolidation conditions, is much greater than that of remodeling samples. Meanwhile, the initial dynamic elastic modulus of sandstone is also greater than that of the mudstone. The dynamic shear modulus ratios of the undisturbed sandstone, the undisturbed mudstone, as well as the remodeling mudstone have the normalization characteristics with the increase of dynamic shear strain. The damping ratio of mudstone is larger than that of the sandstone, and the damping ratio of remolding sample is also greater than that of the undisturbed mudstone. The mudstone has the bad mechanical properties as bearing stratum. 展开更多
关键词 weathered rock mechanical characteristics dynamic elasticity modulus damping ratio COHESION
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Freeze-thaw Resistance of Concrete in Seawater 被引量:1
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作者 SHUI Z H XU H G ZHAN B J 《武汉理工大学学报》 CAS CSCD 北大核心 2010年第17期108-111,共4页
The effect of freeze-thaw cycles in seawater on the performance of concrete was studied in this paper. Concrete samples with different water binder ratio and different component were prepared,and were then put into fr... The effect of freeze-thaw cycles in seawater on the performance of concrete was studied in this paper. Concrete samples with different water binder ratio and different component were prepared,and were then put into fresh water and synthesized seawater. After the experiments of freeze-thaw cycles,the mass loss,relative dynamic elastic modulus (RDEM) and compressive strength of each sample were tested. The results obtained reveal that with the increase of the water binder ratio,the resistance ability of freeze-thaw impact in seawater of concrete decrease dramatically. When the concrete contain 15% fly ash and 20% slag,its resistance ability to the freeze-thaw impact in seawater is the optimal. Compared to the seawater corrosion,the impact of freeze-thaw cycles to the properties of concrete is severer. 展开更多
关键词 freeze-thaw damage seawater mass loss relative dynamic elastic modulus
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