scholarly journals Study of Concrete Strength and Pore Structure Model Based on Grey Relation Entropy

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 432
Author(s):  
Min Zhang ◽  
Xianhua Yao ◽  
Junfeng Guan ◽  
Lielie Li ◽  
Juan Wang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Pore Structure ◽  
Pore Size ◽  
Concrete Strength ◽  
Sensitivity Coefficient ◽  
Structure Model ◽  
Proposed Model ◽  
Compressive Strength Of Concrete ◽  
The Relationship ◽  
Grey Relation

The Grey Relation Entropy (GRE) theory is used to analyze the sensitive pore size that affects the compressive strength of concrete. The relationship between the strength and pore structure is revised based on the sensitivity coefficient. The revised model is used to calculate the compressive strength of concrete. In order to verify the validity of the proposed model, the calculated results are compared with experimental ones, showing satisfactory agreement with a larger correlation than existing methods.

scholarly journals EN 206 Conformity Testing for Concrete Strength in Compression

2016 ◽  
Vol 77 (2) ◽  
Author(s):  
Daneti Saradhi Babu ◽  
Li Wei ◽  
Tam Chat Tim
Keyword(s):  
Compressive Strength ◽  
Concrete Strength ◽  
Concrete Structures ◽  
Strength Level ◽  
Test Results ◽  
Concrete Construction ◽  
The Mean ◽  
Compressive Strength Of Concrete ◽  
Strength In Compression ◽  
The Relationship

The design of concrete structures in accordance with EN 1992-1-1 adopts the characteristic cylinder compressive strength inits equations. EN 206 provides for conformity testing for concrete strength in compression using 150mm diameter by 300mm length cylinders or 150mm cubes only. The complementary standard to EN 206 in UK, BS 8500 (SS 544 in Singapore, MS 523 in Malaysia) has added provisions (clause 12.2) for the use of 100mm cubes for conformity testing. The conformity criteria for 100mm cube specimens are to be the same as those for 150mm cubes. A series of tests based on 3 selected levels of compressive strength has been conducted to examine the relationship between these 3 types of test specimens for compressive strength of concrete. For each strength level, 100 batches of concrete were produced over a period of several months. The test results are presented with analysis based on the mean of 3 numbers for each type of test specimens prepared from the same batch at each time of preparation. The results of this study for the 3 strength levels support the relationship between standard cylinder compressive strength and standard cube compressive strength in EN 206. In addition, results also support the recommendation that standard 100mm cube compressive strength is equivalent to that of standard 150mm cube compressive strength in BS 8500. The use of the small size cubes and certiication of designed concrete promote sustainability in concrete construction.

scholarly journals The Relationship Between the Concrete Strength Values of Curing Specimens Using Microwave and Standard Methods

2021 ◽  
Author(s):  
Zhiyong Tian ◽  
Yuxuan Yang ◽  
Hongtao Peng ◽  
Jiahui Huang ◽  
Yihua Zhou ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Construction Material ◽  
Concrete Strength ◽  
Quick Method ◽  
Standard Methods ◽  
Microwave Curing ◽  
Compressive Performance ◽  
Curing Methods ◽  
Compressive Strength Of Concrete ◽  
The Relationship

As the most widely used construction material, concrete has the characteristics of good compressive performance. The compressive strength of concrete is the most important performance index. However, the compressive strength of concrete measured is generally based on the standard curing period for 28 d. Its period for detection is long. Therefore, it is necessary to study a fast and effective detection method. This paper mainly introduces the experimental method of microwave curing concrete and the relationship between concrete strength values of curing specimens using microwave and standard methods. The experimental results show that concrete specimens exposed to accelerated curing condition under microwave irradiation can increase the strength quickly within a shorter time period depending upon the procedure used in this work. By analysing experimental data, a model of concrete strength at age of 28 d using microwave curing and standard curing methods is established, which can early estimate compressive strength of concrete and provide a quick method for measuring the strength in the field.

scholarly journals Effect of Functional Superplasticizers on Concrete Strength and Pore Structure

2020 ◽  
Vol 10 (10) ◽  
pp. 3496
Author(s):  
Wuju Xun ◽  
Changlong Wu ◽  
Xuefei Leng ◽  
Jiye Li ◽  
Desheng Xin ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Pore Structure ◽  
High Performance ◽  
Concrete Strength ◽  
Reducing Agents ◽  
Reducing Agent ◽  
Polycarboxylic Acid ◽  
X Ray Diffraction ◽  
Hydration Rate ◽  
Compressive Strength Of Concrete

The current work investigates the fluidity and the loss of the flow rate of cement paste and mortar over time, as well as the pore structure and compressive strength of concrete and mortar in the presence of functional polycarboxylic acid high-performance water-reducing agents. The hydration rate, hydration products, and pore structure of the concrete containing different functional polycarboxylic acid superplasticizers were analyzed by means of mercury intrusion test, scanning electron microscopy (SEM), and X-ray diffraction (XRD). The results show that water-reducing agent Z significantly improves the pore structure of concrete and further compacts the structure of concrete and mortar, thereby improving the compressive strength of concrete. Moreover, the shorter side chains and ester functional groups in the structure of water-reducing agent H can slow down cement hydration rate, which lowers the early strength of mortar; nevertheless, at later stages, the pore structure of the concrete and mortar including superplasticizer H is less different from that of the concrete and mortar containing polycarboxylic acid water-reducing agents. Water-reducing agent J performs best but has a weaker effect on the pore structure of concrete and mortar compared to superplasticizer Z; it is also better than naphthalene-based water-reducing agents.

Fabrication of Porous Al2O3 Ceramics by Freeze Drying Technique and Annealing Treatment

2016 ◽  
Vol 848 ◽  
pp. 272-278 ◽  
Author(s):  
Sha Qiu ◽  
Yu Fei Tang ◽  
Kang Zhao
Keyword(s):  
Compressive Strength ◽  
Pore Structure ◽  
Pore Size ◽  
Annealing Time ◽  
Open Porosity ◽  
Sucrose Solution ◽  
Annealing Treatment ◽  
Porous Ceramics ◽  
Crystalline Solid ◽  
Directional Freezing

Porous Al2O3 ceramics were fabricated by directional freezing and low pressure drying with sucrose solution as the cryogenic medium. The pore structure of the porous ceramics was changed by annealing in the environment of higher than the glass transition temperature of sucrose solution after directional freezing because of changing the size and distribution of crystalline solid. The effects of the annealing time on the pore structure, open porosity and mechanical property of porous ceramics were investigated. The results showed that the pore size of porous ceramics increased substantially with the increase of annealing time. The open porosity of porous ceramics changed slightly with the increase of annealing time, while the compressive strength of porous ceramics showed a trend of decrease. The pore size range of porous Al2O3 ceramics fabricated is from 6.0μm to 110.2μm, the range of porosity was 40.35%-64.58%, the compressive strength range of porous Al2O3 ceramics was from 25.9MPa-126.6MPa. The porous Al2O3 ceramics with different pore structure can be obtained by changing the annealing time.

scholarly journals Studi Kuat Tekan Beton Speedcrete Dengan Zat Additive Naphthalene Berdasarkan Variasi Umur

2019 ◽  
Vol 14 (2) ◽  
Author(s):  
Syifa Fauziah ◽  
Anisah Anisah ◽  
Sittati Musalamah
Keyword(s):  
Compressive Strength ◽  
Test Object ◽  
Treatment Process ◽  
Concrete Strength ◽  
Test Machine ◽  
Water Age ◽  
Normal Concrete ◽  
Compressive Strength Of Concrete ◽  
Normal Strength ◽  
Additive Materials

This research aims to determine the maximum compressive strength value of concrete speedcrete using naphthalene additive additive at each test age and compare with normal concrete 28 days. This research used cylindrical test object with diameter 15 cm and height 30 cm. Speedcrete concrete does not undergo the treatment process while the normal concrete test object through the treatment process. Testing compressive strength of concrete speedcrete using Crushing Test Machine tool. In this research the compressive strength was produced by using superplasticizer type naphthalene and compared with normal concrete without using additive. The target quality plan is fc '35 MPa with the use of additive dose of 1.7% of the weight of cement. The results of this research showed an increase in the value of compressive strength of concrete speedcrete with aadditive materials added naphthalene increased with increasing age of concrete. The results showed that the compressive strength of concrete speedcrete with naphthalene additive materials of 12 hours, 18 hours, 28 hours and 48 hours was 0.5 MPa, 17,81 MPa, 31,14 MPa and 45,77 MPa. Normal strength concrete strength with the addition of 20% water age 28 days that is equal to 54.76 MPa.

On Effects of Fly Ash as a Partial Replacement of Cement on Concrete Strength

2012 ◽  
Vol 204-208 ◽  
pp. 3970-3973
Author(s):  
Reagan J. Case ◽  
Kai Duan ◽  
Thuraichamy G. Suntharavadivel
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Concrete Strength ◽  
Cementitious Materials ◽  
Partial Replacement ◽  
Replacement Ratio ◽  
Interface Reactions ◽  
Compressive Strength Of Concrete ◽  
Interface Bonding Strength ◽  
Large Research

As a part of a large research program aiming at the cementitious materials containing recycled materials at Central Queensland University – Australia, the current paper presents the preliminary results of a study on the effects of fly ash, which is used to replace cement in concrete, on the concrete compressive strength. For this purpose, systematic experiments have been carried out to investigate the influences of fly ash ratio and age. The compressive strength of concrete specimens with replacement ratios of 15%, 30% and 45%, and aged 7 and 28 days are measured and are compared with those of the concrete specimens without fly ash at the same ages. The results demonstrate that the strength of fly ash containing concrete improves more slowly but more strongly with aging, than their fly ash free counterparts, and an optimum fly ash replacement ratio exists where the maximum compressive strength of fly ash containing concrete can be achieved, and the maximum strength for the specimens aged 28 days and above is higher that of fly ash free concrete. Furthermore, the observation strength behaviours are analysed and discussed in terms of the influences of fly ash on interface reactions and interface bonding strength.

The Influence of Pore-Strucrure on the Campressive Strength of Hardened Cement Paste

1984 ◽  
Vol 42 ◽  
Author(s):  
Huang Yiun-Yuan ◽  
Ding Wei ◽  
Lu Ping
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Pore Structure ◽  
Cement Paste ◽  
Total Porosity ◽  
Hardened Cement ◽  
Hardened Cement Paste ◽  
New Information ◽  
The Relationship ◽  
Empirical Constants

AbstractThe pore-structure strongly influences the carpressive strength of hardened cement paste (hcp) and other porous materials, as well as other mechanical properties. The simplest but most currently used expression representing the relationship between the pore-structure and compressive strength is fram Balshin: σ = σ0 (l-P)A, in which only the total porosity P is involved as a single parameter and σ0 and A are empirical constants. The influence of pore size distribution and pore shapes etc. are not considered.The authors introduce second parameter w - the factor of relative specific surface area of the pores other than the total porosity P into consideration and a new expression is proposed:σc=K11-p/1+2p(K2(1-p))K3w+K4 all the constants K1 - K4 can be determined experimentally. By using of this expression the new information relating the influence of pore-structure on the caopressive strength of hcp can be predicted.

scholarly journals Effect of basalt aggregates and plasticizer on the compressive strength of concrete

2015 ◽  
Vol 4 (4) ◽  
pp. 520 ◽  
Author(s):  
Mohammad Al-Rawashdeh ◽  
Ashraf Shaqadan
Keyword(s):  
Compressive Strength ◽  
Laboratory Investigation ◽  
Concrete Strength ◽  
Experimental Program ◽  
Sieve Analysis ◽  
Curing Time ◽  
Compressive Test ◽  
Slump Test ◽  
Compressive Strength Of Concrete

The purpose of this research is to investigate the feasibility of using basalt aggregates and plasticizers in concrete mixes. An elaborate experimental program that included a variation of plasticizer and basalt in concrete mixes. The laboratory investigation included measurements of sieve analysis, compressive strength, and slump test. The compressive test was evaluated at 7, 14, 28 days of curing time. The results show significant improvement in concrete strength up to 2% of additive plasticizer after that concrete strength was reduced.

scholarly journals Estimation of In-situ concrete strength using drilling resistance

2019 ◽  
Vol 289 ◽  
pp. 06001
Author(s):  
Serkan Karatosun ◽  
Muhammet Asan ◽  
Oguz Gunes
Keyword(s):  
Compressive Strength ◽  
Concrete Strength ◽  
Condition Assessment ◽  
Assessment Practice ◽  
Destructive Testing ◽  
Seismic Safety ◽  
Concrete Mixtures ◽  
Priority Task ◽  
Compressive Strength Of Concrete ◽  
Drilling Resistance

Rapid and reliable condition assessment of reinforced concrete structures in high seismicity regions is a priority task in estimating their seismic safety. Non-destructive testing (NDT) methods may contribute to the condition assessment practice by providing fast and reliable strength estimation while causing minimal or no damage to the structure. Drilling resistance is an NDT method that has been used for mechanical characterization of natural stone and wood by measuring the force response for constant penetration rate and rotational speed. This paper focuses on the relationship between drilling resistance and compressive strength of concrete, including when it is combined with other NDT methods. Concrete cube samples produced using 6 different concrete mixtures were tested. Correlation equations were then obtained using statistical analysis. The results reveal that it may be possible to reliably estimate the compressive strength of concrete using drilling resistance method.

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