Study on the Secondary Interface in Microstructure of the Superfine Sand Concrete

2014 ◽  
Vol 529 ◽  
pp. 112-116
Author(s):  
Yong Ning Mi ◽  
Xin Shao ◽  
Jin Ting Zhao ◽  
Zhen Guo Wang ◽  
Chuan Yue
Keyword(s):  
Compressive Strength ◽  
High Water ◽  
Interface Structure ◽  
Interface Microstructure ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
History Of ◽  
Calcium Silicon ◽  
Concrete Interface ◽  
Scanning Electron

The superfine sand concrete application in our country has a history of more than half a century. Although we have a certain understanding about the superfine sand concrete, there are few studies of superfine sand concrete interface. This experiment made up different water-cement ratio superfine sand concrete, and used scanning electron microscope to observe the secondary interface structure, the product of interface C-S-H gel had been carried on by the energy spectrum analysis. Results show that the secondary interface microstructure of the low water-cement ratio concrete is denser than high water cement ratio, and also have certain effects on macroscopic compressive strength; C-S-H gel calcium silicon ratio in the secondary interface is between 1.5 and 2.1.

scholarly journals Study on the Strength and Micro Characteristics of Grouted Specimens with Different Superfine Cement Contents

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6709
Author(s):  
Dongyue Zhang ◽  
Zhenqian Ma ◽  
Yihuai Zou ◽  
Hongfei Xie ◽  
Ruichong Guan
Keyword(s):  
Compressive Strength ◽  
Fractal Dimension ◽  
Cement Content ◽  
Uniaxial Compression Test ◽  
Injection Test ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Grouting Material ◽  
Comprehensive Performance ◽  
Scanning Electron

To provide the most effective comprehensive performance grouting material ratio, in this experimental investigation, a total of eight grouted specimens with two water-cement ratios (0.45:1, 0.55:1) and four different superfine cement contents (0%, 30%, 70%, 100%) were evaluated. Based on a uniaxial compression test, the fractal dimension of the fragments, a mercury injection test, and scanning electron microscopy, the effects of the superfine cement content on the strength characteristics and microscopic characteristics of the grouted specimens were studied. The results showed that increasing the superfine cement content could enhance the compressive and tensile strength of the grouted specimens and reduce the fractal dimension of the fragments and the porosity of the grouted specimens. The superfine cement content increased from 0% to 70% when the water-cement ratio was 0.45:1. The compressive strength of the grouted specimens increased from 16.7 MPa to 26.3 MPa, and the fractal dimension decreased from 1.8645 to 1.2301. When the water-cement ratio was 0.55:1, the compressive strength of the grouted specimens increased from 10.5 MPa to 20.6 MPa, and the fractal dimension value decreased from 2.2955 to 1.4458. When the superfine cement content increased from 0% to 100%, the water-cement ratio was 0.45:1. The porosity of the grouted specimens was reduced from 28.41% to 21.62%. When the water-cement ratio was 0.55:1, the porosity of the grouted specimens was reduced from 33.33% to 29.46%.

scholarly journals Use of Nondestructive Testing of Ultrasound and Artificial Neural Networks to Estimate Compressive Strength of Concrete

Buildings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 44
Author(s):  
Fernando A. N. Silva ◽  
João M. P. Q. Delgado ◽  
Rosely S. Cavalcanti ◽  
António C. Azevedo ◽  
Ana S. Guimarães ◽  
...  
Keyword(s):  
Neural Networks ◽  
Compressive Strength ◽  
Artificial Neural Networks ◽  
Cross Sections ◽  
Influential Factors ◽  
Average Error ◽  
Ann Model ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Artificial Neural

The work presents the results of an experimental campaign carried out on concrete elements in order to investigate the potential of using artificial neural networks (ANNs) to estimate the compressive strength based on relevant parameters, such as the water–cement ratio, aggregate–cement ratio, age of testing, and percentage cement/metakaolin ratios (5% and 10%). We prepared 162 cylindrical concrete specimens with dimensions of 10 cm in diameter and 20 cm in height and 27 prismatic specimens with cross sections measuring 25 and 50 cm in length, with 9 different concrete mixture proportions. A longitudinal transducer with a frequency of 54 kHz was used to measure the ultrasonic velocities. An ANN model was developed, different ANN configurations were tested and compared to identify the best ANN model. Using this model, it was possible to assess the contribution of each input variable to the compressive strength of the tested concretes. The results indicate an excellent performance of the ANN model developed to predict compressive strength from the input parameters studied, with an average error less than 5%. Together, the water–cement ratio and the percentage of metakaolin were shown to be the most influential factors for the compressive strength value predicted by the developed ANN model.

Study on Preparation of Solid Concrete Brick with Recycled Aggregate

2013 ◽  
Vol 648 ◽  
pp. 108-111
Author(s):  
Qi Jin Li ◽  
Guo Zhong Li
Keyword(s):  
Compressive Strength ◽  
Mass Fraction ◽  
Recycled Aggregate ◽  
Preparation Process ◽  
Mass Ratio ◽  
Construction Waste ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Optimal Value

The construction waste was processed into recycled aggregate to produce solid construction waste brick with grade of MU20. The preparation process of recycled aggregate and the optimal value of mass ratio of water to cement (water cement ratio) and mass ratio of recycled aggregate to cement was studied. The results shows that when the water cement ratio is 0.86 and the mass ratio of recycled aggregate to cement is 5.5 and the dosage of activator is 0.25% (mass fraction with recycled aggregate), the compressive strength of sample is 22.5MPa and can be satisfied with the requirement of MU20 solid concrete brick.

scholarly journals Influence of Aggregate Gradation on the Engineering Properties of Lightweight Aggregate Concrete

2018 ◽  
Vol 8 (8) ◽  
pp. 1324 ◽  
Author(s):  
How-Ji Chen ◽  
Chung-Hao Wu
Keyword(s):  
Compressive Strength ◽  
Lightweight Aggregate ◽  
Normal Weight ◽  
Engineering Properties ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Gradation ◽  
Aggregate Concrete ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Expanded Shale

Expanded shale lightweight aggregates, as the coarse aggregates, were used to produce lightweight aggregate concrete (LWAC) in this research. At the fixed water-cement ratio, paste quantity, and aggregate volume, the effects of various aggregate gradations on the engineering properties of LWAC were investigated. Comparisons to normal-weight concrete (NWC) made under the same conditions were carried out. From the experimental results, using normal weight aggregates that follow the specification requirements (standard gradation) obtained similar NWC compressive strength to that using uniform-sized aggregates. However, the compressive strength of LWAC made using small uniform-sized aggregates was superior to that made from standard-grade aggregates. This is especially conspicuous under the low water-cement ratio. Even though the workability was affected, this problem could be overcome with developed chemical additive technology. The durability properties of concrete were approximately equal. Therefore, it is suggested that the aggregate gradation requirement of LWAC should be distinct from that of NWC. In high strength LWAC proportioning, following the standard gradation suggested by American Society for Testing and Materials (ASTM) is optional.

Research on Simulation Test of Coal Similar Material

2013 ◽  
Vol 850-851 ◽  
pp. 847-850 ◽  
Author(s):  
Lin Chao Dai
Keyword(s):  
Compressive Strength ◽  
Raw Materials ◽  
Similarity Theory ◽  
Design Method ◽  
Uniform Design ◽  
Physical And Mechanical Properties ◽  
Raw Material ◽  
Similar Material ◽  
Cement Ratio ◽  
Water Cement Ratio

In order to study the coal and gas outburst similar simulation experiment, coal similar material was made up based on the similarity theory. Based on the previous similar material study, the cement, sand, water, activated carbon and coal powder was selected as the raw material of similar material. Meanwhile similar material matching program with 5 factors and 6 levels was designed by using Uniform Design Method. And the physical and mechanical properties of the similar material compressive strength was measured under different proportions circumstances. The relationship between similar material and the raw materials was analyzed. The results show that choosing different materials can compound different similar materials with different requirements. And the water-cement ratio plays a decisive influence on the compressive strength of similar material. The compressive strength of similar material decreases linearly when the water-cement ratio increases.

scholarly journals Effect of Mound Soil on Concrete Produced with River Sand

2014 ◽  
Vol 2 (1) ◽  
pp. 75-82
Author(s):  
Elivs M. Mbadike ◽  
N.N Osadebe
Keyword(s):  
Compressive Strength ◽  
Research Work ◽  
Strength Test ◽  
Control Test ◽  
River Sand ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Compressive Strength Test ◽  
Average Compressive Strength

In this research work, the effect of mound soil on concrete produced with river sand was investigated. A mixed proportion of 1.1.8:3.7 with water cement ratio of 0.47 were used. The percentage replacement of river sand with mound soil is 0%, 5%, 10%, 20%, 30% and 40%. Concrete cubes of 150mm x 150mm x150mm of river sand/mound soil were cast and cured at 3, 7, 28, 60 and 90 days respectively. At the end of each hydration period, the three cubes for each hydration period were crushed and their average compressive strength recorded. A total of ninety (90) concrete cubes were cast. The result of the compressive strength test for 5- 40% replacement of river sand with mound soil ranges from 24.00 -42.58N/mm2 a against 23.29-36.08N/mm2 for the control test (0% replacement).The workability of concrete produced with 5- 40% replacement of river sand with mound soil ranges from 47- 62mm as against 70mm for the control test.

scholarly journals Effect of Water Cement Ratios on Compressive Strength of Palm Kernel Shell Concrete

2019 ◽  
Vol 2 (Issue 1) ◽  
Author(s):  
A.O Adeyemi ◽  
M.A Anifowose ◽  
I.O Amototo ◽  
S.A Adebara ◽  
M.Y Olawuyi
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Fresh Concrete ◽  
Palm Kernel ◽  
Hardened Concrete ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Palm Kernel Shell ◽  
Compressive Strength Of Concrete ◽  
Palm Kernel Shells

This study examined the effect of varying water cement ratio on the compressive strength of concrete produced using palm kernel shell (PKS) as coarse aggregate at different replacement levels. The replacement levels of coarse aggregate with palm kernel shells (PKS) were 0%, 25%, 50%, and 100% respectively. PKS concrete cubes (144 specimens) of sizes 150mm x 150mm x 150mm were cast and cured in water for 7, 14, 21 and 28 days respectively. A mix ratio of 1:2:4 was adopted with water-cement ratio of 0.45, 0.5, and 0.6 respectively while the batching was done by weight. Slump test was conducted on fresh concrete while compressive strength test was carried out on the hardened concrete cubes using a compression testing machine of 2000kN capacity. The result of tests on fresh concrete shows that the slump height of 0.45 water cement ratio (w/c) increases with an increase in PKS%. This trend was similar to 0.50 and 0.60 w/c. However, the compressive strength of concrete cube decreases with an increase in w/c (from 0.45 to 0.60) but increases with respect to curing age and also decreases with increase in PKS%. Concrete with 0.45 water-cement ratio possess the highest compressive strength. It was observed that PKS is not a good substitute for coarse aggregate in mix ratio 1:2:4 for concrete productions. Hence, the study suggest the use of chemical admixture such as superplasticizer or calcium chloride in order to improve the strength of palm kernel shells-concrete.

scholarly journals Mechanical Properties of Concrete with Various Water-Cement Ratio After High Temperature Exposure

2019 ◽  
Vol 2 (2) ◽  
pp. 126-136
Author(s):  
M.I Retno Susilorini ◽  
Budi Eko Afrianto ◽  
Ary Suryo Wibowo
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Temperature ◽  
Modulus Of Elasticity ◽  
Building Materials ◽  
Heating Process ◽  
High Temperature Exposure ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Temperature Exposure

Concrete building safety of fire is better than other building materials such as wood, plastic, and steel,because it is incombustible and emitting no toxic fumes during high temperature exposure. However,the deterioration of concrete because of high temperature exposure will reduce the concrete strength.Mechanical properties such as compressive strength and modulus of elasticity are absolutely corruptedduring and after the heating process. This paper aims to investigate mechanical properties of concrete(especially compressive strength and modulus of elasticity) with various water-cement ratio afterconcrete suffered by high temperature exposure of 500oC.This research conducted experimental method and analytical method. The experimental methodproduced concrete specimens with specifications: (1) specimen’s dimension is 150 mm x 300 mmconcrete cylinder; (2) compressive strength design, f’c = 22.5 MPa; (3) water-cement ratio variation =0.4, 0.5, and 0.6. All specimens are cured in water for 28 days. Some specimens were heated for 1hour with high temperature of 500oC in huge furnace, and the others that become specimen-controlwere unheated. All specimens, heated and unheated, were evaluated by compressive test.Experimental data was analyzed to get compressive strength and modulus of elasticity values. Theanalytical method aims to calculate modulus of elasticity of concrete from some codes and to verifythe experimental results. The modulus elasticity of concrete is calculated by 3 expressions: (1) SNI03-2847-1992 (which is the same as ACI 318-99 section 8.5.1), (2) ACI 318-95 section 8.5.1, and (3)CEB-FIP Model Code 1990 Section 2.1.4.2.The experimental and analytical results found that: (1) The unheated specimens with water-cementratio of 0.4 have the greatest value of compressive strength, while the unheated specimens with watercementratio of 0.5 gets the greatest value of modulus of elasticity. The greatest value of compressivestrength of heated specimens provided by specimens with water-cement ratio of 0.5, while the heatedspecimens with water-cement ratio of 0.4 gets the greatest value of modulus of elasticity, (2) Allheated specimens lose their strength at high temperature of 500oC, (3) The analytical result shows thatmodulus of elasticity calculated by expression III has greater values compares to expression I and II,but there is only little difference value among those expressions, and (4)The variation of water-cementratio of 0.5 becomes the optimum value.

scholarly journals High Temperature Degradation Mechanism of Concrete with Plastering Layer

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 398
Author(s):  
Chihao Liu ◽  
Jiajian Chen
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Thermal Decomposition ◽  
Electron Microscope ◽  
High Temperature ◽  
Thermogravimetric Analysis ◽  
Degradation Mechanism ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Scanning Electron

At present, the research on the high temperature degradation of concrete usually focuses on only the degradation of concrete itself without considering the effect of the plastering layer. It is necessary to take into account the influence of the plastering layer on the high temperature degradation of concrete. With an increase in the water/cement ratio, the explosion of concrete disappeared. Although increasing the water/cement ratio can alleviate the cracking of concrete due to lower pressure, it leads to a decrease in the mechanical properties of concrete after heating. It is proved that besides the water/cement ratio, the apparent phenomena and mechanical properties of concrete at high temperature can be affected by the plastering layer. The plastering layer can relieve the high temperature cracking of concrete, and even inhibit the high temperature explosion of concrete with 0.30 water/cement ratio. By means of an XRD test, scanning electron microscope test and thermogravimetric analysis, it is found that the plastering layer can promote the rehydration of unhydrated cement particles of 0.30 water/cement ratio concrete at high temperature and then promote the mechanical properties of concrete at 400 °C. However, the plastering layer accelerated the thermal decomposition of C-S-H gel of concrete with a water/cement ratio of 0.40 at high temperature, and finally accelerate the decline of mechanical property of concrete. To conclude, the low water/cement ratio and plastering layer can delay the deterioration of concrete at high temperature.

scholarly journals The Effect of Nano Metakaolin Material on Some Properties of Concrete

2013 ◽  
Vol 6 (1) ◽  
pp. 50-61
Author(s):  
Amer M. Ibrahem ◽  
Shakir A. Al-Mishhadani ◽  
Zeinab H.Naji
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Portland Cement ◽  
Water Absorption ◽  
Thermal Activation ◽  
Ordinary Portland Cement ◽  
Splitting Tensile Strength ◽  
Kaolin Clay ◽  
Cement Ratio ◽  
Water Cement Ratio

This investigation aimed to study the effect of nano metakaolin ( NMK ) on some properties (compressive strength ,splitting tensile strength & water absorption ) of concrete. The nano metakaolin (NMK) was prepared by thermal activation of kaolin clay for 2 hours at 750 Ċ. The cement used in this investigation consists of ordinary Portland cement (OPC). The OPC was partially substituted by NMK of ( 3, 5 & 10%) by weight of cement. The C45 concrete was prepared , using water/cement ratio ( W/c) of (0.53) .The Water absorption was tested at 28 days while the tests (compressive strength ,splitting tensile strength) were tested at ages of (7, 28, 60,& 90) days . The compressive strength and splitting tensile strength of concrete with NMK were higher than that of reference concrete with the same W/c ratio.The improvement in the compressive strength when using NMK was (42.2, 55.8 , 63.1% ) at age 28 days for ( 3%, 5%, &10% ) replacement of NMK respectively whereas the improvement in the splitting tensile strength was (0% , 36% & 46.8 %) at age of 28 days when using (3%, 5%, &10% ) NMK respectively. The improvement in the water absorption was (16.6%, 21.79%, &25.6 ) when using (3, 5, &10% )NMK.

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