The Influence of Different Subbase Materials on the Crack of Cement Stabilized Macadam Base during Construction

2012 ◽  
Vol 591-593 ◽  
pp. 955-959 ◽  
Author(s):  
Xiao Feng Liao ◽  
Fen Xiao ◽  
Zhong Da Chen ◽  
Lei Xing
Keyword(s):  
Tensile Stress ◽  
Shrinkage Strain ◽  
Mechanical Parameters ◽  
Tensile Stresses ◽  
Shrinkage Crack ◽  
Dry Shrinkage ◽  
Base Course ◽  
Shrinkage Coefficient ◽  
Crack Space

According to actual axle load data and the measured mechanical parameters of cement stabilized macadam material with different cement dosages, the bottom tensile stresses of different subbase structures are calculated and the results show that: to graded gravel subbase, the weight of construction vehicle is inadvisable to be more than 35t and the cement dosage of base course shall be more than 3.0%; and, the maximum bottom tensile stress of graded gravel subbase shall be much more than that of lime-flyash soil subbase. According to the measured dry shrinkage strain and dry shrinkage coefficient, the dry shrinkage crack space of base course is analyzed and the results show that: under the same cement dosage, the crack space of the base course with graded gravel subbase is smaller than that of lime-flyash soil subbase; with the increase of cement dosage, the crack space of base course increase first and then decrease, and when the cement dosage is 3.5%, the dry shrinkage strain and dry shrinkage coefficient is minimum and the crack space of base course is maximum.

Research on Shrinkage Chemical Properties of Cement Stabilized Macadam Material Based on a Multi-dimensional Expansion and Shrinkage Tester

2020 ◽  
Vol 71 (6) ◽  
pp. 418-428
Author(s):  
Aiping Fei ◽  
Wensheng Zhang ◽  
Tiezhi Zhang
Keyword(s):  
Water Loss ◽  
Room Temperature ◽  
Loss Rate ◽  
Chemical Properties ◽  
Shrinkage Strain ◽  
Fine Aggregate ◽  
Water Loss Rate ◽  
Dry Shrinkage ◽  
Reflection Crack ◽  
Shrinkage Coefficient

In order to find out the shrinkage law of cement stabilized macadam material under specific conditions, this paper studied the expansion and shrinkage properties of cement stabilized macadam material under two environmental conditions, five kinds of cement dosage conditions, suspended compacted type and skeleton compaced type based on the multi-dimensional expansion and shrinkage tester. Through the test comparison, it is confirmed that the water loss rate of cement stabilized macadam material increases with the increase of cement dosage, showing a general change rule of rising first and then stabilizing. The average increase of the total water loss rate of suspended compacted cement stabilized macadam at room temperature was greater than that of the skeleton compacted cement stabilized macadam. The dry shrinkage strain also follows the above trend. Either at room temperature or under the conditions of dry shrinkage box, the water loss rate of suspended compacted cemeny stabilized macadam is higher than that of skeleton compacted cement stabilized macadam , which can be up to 3.23% higher. By comparing the temperature shrinkage coefficient under the high and low temperature environment, the temperature coefficient of the skeleton compacted cement stabilized macadam is smaller than that of the suspended compacted cement stabilized macadam. The temperature shrinkage coefficient of the suspended compacted cement stabilized macadam increases by 5.56% on average for each 0.5% increase of the cement dosage, and the temperature shrinkage coefficient of the skeleton compacted cement stabilized macadam increases by 6.33% on average. Through the comparative analysis of tests, it can be found that the anti-reflection crack ability of the skeleton compacted cement stabilized macadam material is better, and the fine aggregate content should be strictly controlled in the construction.

Experimental Research on Shrinkage Properties of Cement Stabilized Iron Tailings Sand Mixture

2013 ◽  
Vol 423-426 ◽  
pp. 1301-1307
Author(s):  
Bao Feng Pan ◽  
Hong Yu Shi ◽  
Chang Hong Zhou
Keyword(s):  
Experimental Research ◽  
Shrinkage Strain ◽  
Road Engineering ◽  
Sand Mixture ◽  
Tailings Sand ◽  
Significant Difference ◽  
Dry Shrinkage ◽  
Shrinkage Coefficient

Variation laws of cement stabilized iron tailings sand mixtures loss of water, dry shrinkage strain and temperature shrinkage coefficient have been obtained by the indoor shrinkage test, which are compared with cement stabilized gravel. Results of test show that its dry shrinkage strain are greater than cement stabilized gravel. There is no significant difference of temperature shrinkage coefficient between two mixtures above 273.15K, but this index of cement stabilized iron tailings sand mixture is significantly larger than that of cement stabilized gravel below 273.15K, which provides theoretical references for promotion and application of iron tailings sand in road engineering.

scholarly journals Finite Element Simulation and Multi-Factor Stress Prediction Model for Cement Concrete Pavement Considering Void under Slab

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5294
Author(s):  
Bangyi Liu ◽  
Yang Zhou ◽  
Linhao Gu ◽  
Xiaoming Huang
Keyword(s):  
Finite Element ◽  
Tensile Stress ◽  
Concrete Slab ◽  
Three Dimensional ◽  
Mesh Size ◽  
Maximum Tensile Stress ◽  
Concrete Pavement ◽  
Slab Thickness ◽  
Void Size ◽  
Tensile Stresses

Uneven support as result of voids beneath concrete slabs can lead to high tensile stresses at the corner of the slab and eventually cause many forms of damage, such as cracking or faulting. Three-dimensional (3D) finite element models of the concrete pavement with void are presented. Mesh convergence analysis was used to determine the element type and mesh size in the model. The accuracy of the model is verified by comparing with the calculation results of the code design standards in China. The reliability of the model is verified by field measurement. The analysis shows that the stresses are more affected at the corner of the slab than at the edge. Impact of void size and void depth at the slab corner on the slab stress are similar, which result in the change of the position of the maximum tensile stress. The maximum tensile stresses do not increase with the increase in the void size for relatively small void size. The maximum tensile stress increases rapidly with the enlargement in the void size when the size is ≥0.4 m. The increments of maximum tensile stress can reach 183.7% when the void size is 1.0 m. The increase in slab thickness can effectively reduce maximum tensile stress. A function is established to calculate the maximum tensile stress of the concrete slab. The function takes into account the void size, the slab thickness and the vehicle load. The reliability of the function was verified by comparing the error between the calculated and simulated results.

Effect of silica fume on durability of concrete composites containing fly ash

2013 ◽  
Vol 20 (1) ◽  
pp. 57-65 ◽  
Author(s):  
Peng Zhang ◽  
Qing-fu Li
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Shrinkage Strain ◽  
Carbonation Depth ◽  
Freeze Thaw ◽  
Slump Flow ◽  
Carbonation Resistance ◽  
Dry Shrinkage ◽  
Shrinkage Property ◽  
Durability Of Concrete

AbstractIn this paper, the effect of silica fume on the workability and durability of concrete composites containing fly ash, including water impermeability, dry shrinkage property, carbonation resistance and freeze-thaw resistance, are presented. Four different silica fume contents (3%, 6%, 9% and 12%) were used. The results indicate that the addition of silica fume has greatly improved the durability of water impermeability, the carbonation resistance and the freeze-thaw resistance of the concrete composites containing fly ash. With the increase in silica fume content, the length of water permeability and the carbonation depth of the specimens decrease gradually, and the relative dynamic elastic modulus of the specimens has a tendency to increase. However, the addition of silica fume has a little adverse effect on the workability and dry shrinkage property of concrete composites containing fly ash. With the increase in silica fume content, both the slump and the slump flow decrease gradually, and the dry shrinkage strain increases gradually.

scholarly journals Mechanical Properties and Shrinkage Behavior of Concrete-Containing Graphene-Oxide Nanosheets

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 590 ◽  
Author(s):  
Zengshun Chen ◽  
Yemeng Xu ◽  
Jianmin Hua ◽  
Xu Wang ◽  
Lepeng Huang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Graphene Oxide ◽  
Flexural Strength ◽  
Elasticity Modulus ◽  
Shrinkage Strain ◽  
Graphene Oxide Nanosheets ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Dry Shrinkage ◽  
Shrinkage Behavior

Graphene oxide (GO) has been widely used as an additive due to its numerous unique properties. In this study, the compressive strength, flexural strength and elasticity modulus of concrete containing 0.02 wt%, 0.05 wt % and 0.08 wt % GO, and its dry shrinkage performance have been experimentally investigated. After the sample preparation, apparatus for compression test and flexural test were used to test the relevant properties of concrete containing GO. The dial indicators were used to measure the shrinkage of samples. The results indicate that GO can considerably improve the compressive strength, flexural strength, and elasticity modulus of concrete at the concrete age of 28 days by 4.04–12.65%, 3.8–7.38%, and 3.92–10.97%, respectively, which are substantially smaller than the increment at the age of 3 d by 5.02–21.51%, 4.25–13.06%, and 6.07–27.45% under a water-cement ratio of 0.35. It was also found that GO can increase the shrinkage strain of concrete. For example, at the age of 60 days, 0.02 wt%, 0.05 wt% and 0.08 wt% GO can increase the shrinkage strain of ordinary concrete by 1.99%, 5.79% and 7.45% respectively under a water-cement ratio of 0.49. The study has advanced our understanding on mechanical and shrinkage behavior of concrete containing GO.

scholarly journals Local, transient tensile stress on the nuclear membrane causes membrane rupture

2019 ◽  
Vol 30 (7) ◽  
pp. 899-906 ◽  
Author(s):  
Qiao Zhang ◽  
Andrew C. Tamashunas ◽  
Ashutosh Agrawal ◽  
Mehdi Torbati ◽  
Aditya Katiyar ◽  
...  
Keyword(s):  
Tensile Stress ◽  
Nuclear Membrane ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Tensile Stresses ◽  
Membrane Rupture ◽  
Nuclear Membranes ◽  
Compressive Stresses ◽  
Diffusive Fluxes ◽  
Nuclear Deformations

Cancer cell migration through narrow constrictions generates compressive stresses on the nucleus that deform it and cause rupture of nuclear membranes. Nuclear membrane rupture allows uncontrolled exchange between nuclear and cytoplasmic contents. Local tensile stresses can also cause nuclear deformations, but whether such deformations are accompanied by nuclear membrane rupture is unknown. Here we used a direct force probe to locally deform the nucleus by applying a transient tensile stress to the nuclear membrane. We found that a transient (∼0.2 s) deformation (∼1% projected area strain) in normal mammary epithelial cells (MCF-10A cells) was sufficient to cause rupture of the nuclear membrane. Nuclear membrane rupture scaled with the magnitude of nuclear deformation and the magnitude of applied tensile stress. Comparison of diffusive fluxes of nuclear probes between wild-type and lamin-depleted MCF-10A cells revealed that lamin A/C, but not lamin B2, protects the nuclear membranes against rupture from tensile stress. Our results suggest that transient nuclear deformations typically caused by local tensile stresses are sufficient to cause nuclear membrane rupture.

Study on Durability of High Bending Strength Pavement Concrete

2012 ◽  
Vol 594-597 ◽  
pp. 1372-1376
Author(s):  
Wei Hong Guo
Keyword(s):  
Wear Resistance ◽  
Bending Strength ◽  
Drying Shrinkage ◽  
Fatigue Property ◽  
Plain Concrete ◽  
Shrinkage Strain ◽  
Test Results ◽  
Concrete Material ◽  
Shrinkage Coefficient ◽  
Pavement Concrete

In order to explore the durability of high bending strength pavement concrete, adding silica flour, fibrous reticulum, SD emulsion and HG emulsion separately in concrete mixture, the shrinkage characteristic, wear resistance and fatigue property of different high bending strength pavement concrete are tested, and contrastive analysis with the plain concrete material is researched. The test results show that the early contraction of HBSPC is bigger, but the total drying shrinkage strain is smaller than plain concrete, and the drying shrinkage stable stage of HBSPC is shorter than plain concrete. The temperature shrinkage of HBSPC and plain concrete is uniform basically, the temperature shrinkage coefficient of HBSPC is lower than the plain concrete in the negative warm area and warm area, but it is higher in 0 °C neighbor. The mixtures of the material enhance the wear resistance and fatigue property of concrete.

Effect of Nano Materials on Durability of High Performance Concrete

2013 ◽  
Vol 742 ◽  
pp. 220-223 ◽  
Author(s):  
Yu Xi An
Keyword(s):  
Water Permeability ◽  
High Performance ◽  
High Performance Concrete ◽  
Shrinkage Strain ◽  
Nano Materials ◽  
Carbonation Depth ◽  
Shrinkage Cracking ◽  
Carbonation Resistance ◽  
Dry Shrinkage

The aim of this study was to study the effect of nanoSiO2 on durability of high performance concrete. Four different nanoSiO2 contents (1%, 2%, 3% and 4%) were used. The results indicate that the content of nanoSiO2 has great effect on the durability of high performance concrete. With the increase of nanoSiO2 content, both of the length of water permeability and the carbonation depth of concrete are decreasing gradually, and the water impermeability and the carbonation resistance of concrete are increasing gradually. However, with the increase of nanoSiO2 content, there is a tendency of increase on the dry shrinkage strain of 90 days of high performance concrete, and the anti-dry-shrinkage cracking property of concrete is decreasing.

Anisotropic Strain and Training of Conducting Polymer Artificial Muscles under High Tensile Stresses

2009 ◽  
Vol 1224 ◽  
Author(s):  
Keiichi Kaneto ◽  
Hikaru Hashimoto ◽  
Kazuo Tominaga ◽  
Tomokazu Sedai ◽  
Wataru Takashima
Keyword(s):  
Tensile Stress ◽  
Conducting Polymer ◽  
Polymer Chains ◽  
Artificial Muscles ◽  
Tensile Stresses ◽  
Polyaniline Films ◽  
Electrochemical Cycling ◽  
The One ◽  
And Training ◽  
Anisotropic Deformation

AbstractElectrochemomechanical deformations (ECMD) of conducting polymer, polyaniline, films are studied to investigate the creeping and the memory effects. During electrochemical cycling under high tensile stresses up to 5 MPa, the films showed a remarkable creeping, resulting in the one dimensional anisotropic deformation. However, the creeping was recovered by release of the tensile stress, restoring from the anisotropic deformation. It was also found that the strain of ECMD after applying high tensile stresses increased compared with that before applying the large tensile stress. The result indicates that the artificial muscles are strengthened in strain by the experience of large tensile loads, and discussed taking the rheology of electrochemical cycles, viz., electrostatic crosslinking of polymer chains by oxidation and release of crosslinking by reduction.

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