Influence of Air Content on the Compressive Strength of Concrete

2012 ◽  
Vol 535-537 ◽  
pp. 1790-1793
Author(s):  
Rui Ying Bai ◽  
Ji Wei Cai ◽  
Ji Xu Wu ◽  
Gong Lei Wei
Keyword(s):  
Compressive Strength ◽  
Concrete Strength ◽  
The Other ◽  
Strength Grade ◽  
Air Content ◽  
Other Hand ◽  
Compressive Strength Of Concrete

The influence of air content on compressive strength of C20，C30，C40 and C50 concrete was investigated in this paper. The result shows that this relationship varied with concrete strength grade. For C20~C40 concrete, the air content increases with addition of air entraining agent, while a maximum air content value appears for C50 concrete. The compressive strength of C20 decrease slightly with the air content, on the other hand, that of C40 significantly decreases relatively.

Effects of 0-30% Wood Ashes as a Substitute of Cement on the Strength of Concretes

2022 ◽  
Author(s):  
Theodore Gautier Bikoko ◽  
Jean Claude Tchamba ◽  
Valentine Yato Katte ◽  
Divine Kum Deh
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Greenhouse Gases ◽  
Negative Influence ◽  
Wood Ash ◽  
The Other ◽  
Other Hand ◽  
Strength Tests ◽  
Compressive Strength Of Concrete ◽  
Curing Age

To fight against the high cost and the increasing scarcity of cement and at the same time to reduce the CO2 greenhouse gases emission associated with the production of Portland cement, two types of wood ashes as a substitute of cement in the production of concretes were investigated. In this paper, we substituted cement by two types of species of wood ashes namely, avocado and eucalyptus ashes following the proportions ranging from 0% to 30 % on one hand, and on the other hand, we added these two types of species of wood ashes namely, avocado and eucalyptus ashes following the proportions ranging from 0% to 10 % by weight of cement in the concrete samples. After 7, 14 and 28 days of curing, compressive strength tests were conducted on these concrete samples. The findings revealed that using wood ashes as additives/admixtures or as a substitute of cement in the production/manufacturing of concrete decreased the compressive strength of concrete. Hence, it can be said that wood ash has a negative influence on the strength of concrete. At three percent (3%) and ten percent (10%) of addition, the wood ash from eucalyptus specie offers better resistance compared to the wood ash from avocado specie, whereas at five percent (5%) of addition, the wood ash from avocado specie offers better resistance compared to the wood ash from eucalyptus specie. At thirty percent (30%) of substitution, the wood ash from eucalyptus specie offers better resistance compared to the wood ash from avocado specie. The compressive strengths increase with the increase of curing age.

Effects of Concrete Compositions on the Elastic Modulus

2021 ◽  
Vol 322 ◽  
pp. 41-47
Author(s):  
Rudolf Hela ◽  
Lenka Bodnárová ◽  
Klára Křížová
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Negative Impact ◽  
The Other ◽  
Technological Factors ◽  
Factors Influencing ◽  
Other Hand ◽  
Eurocode 2 ◽  
Compressive Strength Of Concrete ◽  
Reducing Costs

The paper comments on the influence of various technological factors influencing the values of elastic modulus. Today, the composition of concrete combines the classic input components with the significant use of mixed cements, active admixtures and superplasticizers in order to achieve the required compressive strength of concrete and durability while reducing costs. On the other hand, the composition of these concretes has a negative impact on the elastic modulus which are significantly lower than the values derived from compressive strength in Eurocode 2. At the end of the article is a list of measures that are a prerequisite for obtaining the required concrete elastic modulus.

USAGE OF CALCIUM CARBONATE BIODEPOSITION IN MODIFICATION OF CEMENTITIOUS COMPOSITES

2018 ◽  
Vol 172 (52) ◽  
pp. 11-22
Author(s):  
Daniel Zawal ◽  
Krzysztof Górski ◽  
Agnieszka Dobosz
Keyword(s):  
Compressive Strength ◽  
Calcium Carbonate ◽  
Construction Materials ◽  
The Other ◽  
Cementitious Composites ◽  
Historic Buildings ◽  
Effective Solution ◽  
Other Hand ◽  
Compressive Strength Of Concrete ◽  
Durability Of Concrete

Biodeterioration of construction materials is an undesired phenomenon, generating high costs of constraction repairs. On the other hand, occurrence of some bacteria can affect prevention and self repair of fractures formed in concrete. Biodeposition is an effective solution for increasing compressive strength of concrete, extending durability of concrete constructions and renovating limestone elements in facades of historic buildings.

scholarly journals Study on the Effect of the Strength Grade on the Creep Behavior of Concrete

2015 ◽  
Vol 9 (1) ◽  
pp. 881-887 ◽  
Author(s):  
Zheng Wenzhong ◽  
Tang Can
Keyword(s):  
Compressive Strength ◽  
Creep Behavior ◽  
Concrete Strength ◽  
High Ratio ◽  
Creep Model ◽  
Influence Coefficient ◽  
Concrete Creep ◽  
Strength Grade ◽  
Creep Coefficient ◽  
Compressive Strength Of Concrete

The internal factors which influenced the concrete creep behavior have been mostly divided by the creep model at home and abroad, but the computing is complex. In order to directly use the creep model in engineering conveniently, it is necessary to consider the effect of concrete strength grade on concrete creep. 302 creep test data with a loading age of 28 d, a lasting age of 360 d, and meet certain environmental conditions were collected. The strength of prism with different aspect ratio and high ratio of cylinder specimen was equivalent to the standard cube strength. The relationship between the creep compliance and creep degree and the cube compressive strength of concrete was fitted, and influence coefficient of the strength grade on the creep degree and creep coefficient were obtained. The influence coefficient can be used to determine creep value, creep coefficient, creep degree of concrete. In this paper, the effect of the strength grade on creep was considered directly, which involves the cube compressive strength of concrete from 15 MPa to 180MPa. The research results can be used in broad scope and has certain practical value.

scholarly journals A Cameroonian Study on Mixing Concrete with Wood Ashes: Effects of 0-30% Wood Ashes as a Substitute of Cement on the Strength of Concretes

2021 ◽  
Vol 31 (5) ◽  
pp. 275-282
Author(s):  
Théodore Gautier L.J. Bikoko
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Greenhouse Gases ◽  
Negative Influence ◽  
Wood Ash ◽  
The Other ◽  
Other Hand ◽  
Strength Tests ◽  
Compressive Strength Of Concrete ◽  
Curing Age

To fight against the high cost and the increasing scarcity of cement and at the same time to reduce the CO2 greenhouse gases emission associated with the production of Portland cement, two types of wood ashes as a substitute of cement in the production of concretes were investigated. In this paper, we substituted cement by two types of species of wood ashes namely, avocado and eucalyptus ashes following the proportions ranging from 0% to 30% on one hand, and on the other hand, we added these two types of species of wood ashes namely, avocado and eucalyptus ashes following the proportions ranging from 0% to 10% by weight of cement in the concrete samples. After 7, 14 and 28 days of curing, compressive strength tests were conducted on these concrete samples. The findings revealed that using wood ashes as additives/admixtures or as a substitute of cement in the production/manufacturing of concrete decreased the compressive strength of concrete. Hence, it can be said that wood ash has a negative influence on the strength of concrete. At three percent (3%) and ten percent (10%) of addition, the wood ash from eucalyptus specie offers better resistance compared to the wood ash from avocado specie, whereas at five percent (5%) of addition, the wood ash from avocado specie offers better resistance compared to the wood ash from eucalyptus specie. At thirty percent (30%) of substitution, the wood ash from eucalyptus specie offers better resistance compared to the wood ash from avocado specie. The compressive strengths increase with the increase of curing age.

Effect of strain rate, off-axis loading and high-velocity impact damage on the compressive strength of C/SiC composite

2018 ◽  
Vol 53 (4) ◽  
pp. 535-546 ◽  
Author(s):  
M Altaf ◽  
S Singh ◽  
VV Bhanu Prasad ◽  
Manish Patel
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
High Velocity ◽  
Impact Damage ◽  
The Other ◽  
High Velocity Impact ◽  
Fibre Bundles ◽  
Velocity Impact ◽  
Kink Bands ◽  
Other Hand

The compressive strength of C/SiC composite at different strain rates, off-axis orientations and after high-velocity impact was studied. The compressive strength was found to be 137 ± 23, 130 ± 46 and 162 ± 33 MPa at a strain rate of 3.3 × 10−5, 3.3 × 10−3, 3.3 × 10−3 s−1, respectively. On the other hand, the compressive strength was found to be 130 ± 46, 99 ± 23 and 87 ± 9 MPa for 0°/90°, 30°/60° and 45°/45° fibre orientations to loading direction, respectively. After high-velocity impact, the residual compressive strength of C/SiC composite was found to be 58 ± 26, 44 ± 18 and 36 ± 3.5 MPa after impact with 100, 150 and 190 m/s, respectively. The formation of kink bands in fibre bundles was found to be dominant micro-mechanism for compressive failure of C/SiC composite for 0°/90° orientation. On the other hand, delamination and the fibre bundles rotation were found to be the dominant mechanism for off-axis failure of composite.

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.

The Effect of Different Curing Conditions on Compressive Strength of Concrete

2017 ◽  
Vol 60 (3) ◽  
pp. 147-153
Author(s):  
Muhammad Arslan ◽  
Muhammad Asif Saleem ◽  
Maria Yaqub ◽  
Muhammad Saleem Khan
Keyword(s):  
Compressive Strength ◽  
Research Work ◽  
Concrete Structures ◽  
Strength Test ◽  
The Other ◽  
Cylindrical Shape ◽  
Curing Conditions ◽  
Compressive Strength Test ◽  
Different Types ◽  
Compressive Strength Of Concrete

The focus of this research work was to analyse the effect of different types of curing oncompressive strength of concrete structures. For this purpose, 54 test specimens of cylindrical shape wereprepared. These specimens were cured with different methods and were tested on different age days toanalyse the effect of curing on compressive strength. Test specimens cured with conventional water curingmethod gives the highest results as compared to the other adopted methods.

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.

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.

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