scholarly journals Resistencia de concreto con agregado de alta absorción y baja relación a/c

2012 ◽  
Vol 2 (1) ◽  
pp. 21-28
Author(s):  
R. G. Solís ◽  
E. Moreno ◽  
E. Arjona
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Construction Site ◽  
Cement Ratio ◽  
Limestone Aggregate ◽  
Concrete Mixtures ◽  
Water To Cement Ratio ◽  
Maximum Compressive Strength ◽  
Crushed Limestone ◽  
High Absorption

RESUMENLa resistencia del concreto depende de la calidad de la pasta de cemento y de las características de los agregados pétreos. La primera es controlada por la relación agua - cemento, mientras que las propiedades de los agregados generalmente no pueden ser manipuladas ya que se suele utilizar aquellos que están disponibles cerca de la construcción. En muchas regiones rocas con propiedades no deseables son utilizadas como agregado. Por lo tanto, el objetivo de este trabajo fue responder a la pregunta sobre cuál sería la máxima resistencia de diseño que se podría utilizar para concretos fabricados con un tipo específico de agregados obtenidos a partir de la trituración de roca caliza de alta absorción. Se probaron concretos con seis relaciones agua - cemento y dos tamaños de agregado grueso. Se concluyó que con los agregados estudiados es posible fabricar concretos de hasta 500 k/cm2 de f’c.Palabras clave: Absorción; agregados calizos; concreto; relación agua/cemento; resistencia.ABSTRACTConcrete strength depends on the cement paste quality and on the characteristics of the aggregates. The former is controlled by the water to cement ratio, while the properties of the aggregate, in general, cannot be manipulated as it is customary to employ the ones available near the construction site. In many regions rocks with no desirable properties are employed as aggregates. Therefore, the aim of this study was to answer the question about what would that be the maximum compressive strength attainable in concrete made with a specific type of aggregate obtained from crushed limestone of high absorption. Concrete mixtures involved six water to cement ratios and two sizes of coarse aggregate. It was concluded that with this type of aggregate it is possible to made concrete with compressive strength up to 500 k/cm2 of f’c.Key words: Absorption; compressive strength; concrete; limestone aggregate; water/cement ratio.

scholarly journals Use of Recycled Tyre Rubber in Non-structural Concrete

2018 ◽  
Vol 203 ◽  
pp. 06001
Author(s):  
Muhammad Bilal Waris ◽  
Hussain Najwani ◽  
Khalifa Al-Jabri ◽  
Abdullah Al-Saidy
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Coarse Aggregate ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Structural Concrete ◽  
Cement Ratio ◽  
Mix Proportion ◽  
Water To Cement Ratio ◽  
Concrete Blocks

To manage tyre waste and conserve natural aggregate resource, this research investigates the use of waste tyre rubber as partial replacement of fine aggregates in non-structural concrete. The research used Taguchi method to study the influence of mix proportion, water-to-cement ratio and tyre rubber replacement percentage on concrete. Nine mixes were prepared with mix proportion of 1:2:4, 1:5:4 and 1:2.5:3; water-to-cement ratio of 0.25, 0.35 and 0.40 and rubber to fine aggregate replacement of 20%, 30% and 40%. Compressive strength and water absorption tests were carried out on 100 mm cubes. Compressive strength was directly proportional to the amount of coarse aggregate in the mix. Water-to-cement ratio increased the strength within the range used in the study. Strength was found to be more sensitive to the overall rubber content than the replacement ratio. Seven out of the nine mixes satisfied the minimum strength requirement for concrete blocks set by ASTM. Water absorption and density for all mixes satisfied the limits applicable for concrete blocks. The study indicates that mix proportions with fine to coarse aggregate ratio of less than 1.0 and w/c ratio around 0.40 can be used with tyre rubber replacements of up to 30 % to satisfy requirements for non-structural concrete.

scholarly journals Influence of cement replacement with limestone filler on the properties of concrete

2021 ◽  
Vol 64 (3) ◽  
pp. 165-170
Author(s):  
Ksenija Tešić ◽  
Snežana Marinković ◽  
Aleksandar Savić
Keyword(s):  
Particle Size ◽  
Compressive Strength ◽  
Mineralogical Composition ◽  
Limestone Filler ◽  
Green Concrete ◽  
Cement Ratio ◽  
Cement Replacement ◽  
Concrete Mixtures ◽  
Water To Cement Ratio ◽  
Compressive Strength Of Concrete

This paper presents an experimental research of one type of green concrete in which Portland cement was replaced with two types of limestone filler of the same origin and mineralogical composition, but with a different fineness of particles. Ten concrete mixtures were designed in which 0%, 15%, 30% and 45% (by mass) of cement were replaced with filler. The water to cement ratio for each mixture was constant (w/c=0.54), and the water to powder ratio was decreasing with increasing cement replacement. Particle size distribution was selected using Funk and Dinger, as well as using Fuller's model. The results showed that it is possible to increase the compressive strength of concrete by reducing 45% of cement, but further research should be focused on improving the workability.

Basic Mechanical Properties of Concrete with Machine-Made Sand and Recycled Coarse Aggregate

2013 ◽  
Vol 357-360 ◽  
pp. 1102-1105 ◽  
Author(s):  
Shun Bo Zhao ◽  
Qi Guo ◽  
Guang Xin Li ◽  
Yan Feng Su
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Coarse Aggregate ◽  
Cement Ratio ◽  
Recycled Coarse Aggregate ◽  
Water To Cement Ratio ◽  
Current Specification ◽  
Current Design ◽  
Axial Compressive Strength

Experimental study was carried out on the concrete mixed with machine-made sand and recycled coarse aggregate (MSRAC), three strength grades of concrete were designed by changing the water to cement ratio as 0.36, 0.45 and 0.55, while the sand ratio varied in a range of 32%~38%, 32%~42% and 38%~44% successively. The workability and the mechanical properties such as compressive and splitting tensile strengths and elastic modulus of MSRAC were tested. The results show that although the mechanical properties of MSRAC were influenced by sand ratio, they were still controlled by the water to cement ratio. The ratio of axial compressive strength to cubic compressive strength and the elastic modulus of MSRAC basically satisfy the specifications of the current design code for concrete structures. It should be noticed that the tensile strength of MSRAC is lower than current specification, and tends to reduce with the increase of water to cement ratio.

scholarly journals Experimental Investigation of the Production of Sustainable Lightweight Concrete

2020 ◽  
Vol 38 (11A) ◽  
pp. 1652-1665
Author(s):  
Mouhammed J. Lafta
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Lightweight Concrete ◽  
Dry Density ◽  
Normal Concrete ◽  
Cement Ratio ◽  
Water To Cement Ratio ◽  
Concrete Production ◽  
Concrete Mix

An experimental study on four types of coarse aggregate was conducted to produce lightweight concrete. These four types are namely; white limestone, red limestone, clay brick fragments, and pumice. Ordinary Portland cement was used for all examined mixes. Water to cement ratio (w/c) was modified according to the effect of coarse aggregate type on the workability of the resulted concrete for each mix. The reference concrete mix, which is normal concrete, water to cement ratio used was (0.5). The investigated characteristics for all concrete mixes were workability, compressive strength, dry density, absorption, and thermal conductivity. Results indicated that the aggregate type significantly affects most of the properties of lightweight concrete mixes such as workability, density, and thermal insulation for all tested types of concrete. All investigated specimens indicated improvement in terms of density, workability, and thermal conductivity when compared to the reference concrete mix. Yet, it was derived from the testing results that using pumice in lightweight concrete production is the optimum option among the other examined types. When compared to normal concrete, this type of lightweight concrete showed a 41% decrease in dry density, nearly 72.54% decrease in thermal conductivity, and about 12% increase in workability. However, it is vital to notice that due to the low compressive strength and the relatively high absorption capability for all the examined types of lightweight concrete, it is suggested to use these types of concrete for non-structural walls that are not subjected to or exposed to high humidity.

scholarly journals Carbonation Coefficients from Concrete Made with High-Absorption Limestone Aggregate

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Eric I. Moreno
Keyword(s):  
Cement Paste ◽  
Coarse Aggregate ◽  
Point Of View ◽  
Fine Aggregate ◽  
High Porosity ◽  
Accelerated Carbonation ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Limestone Aggregate ◽  
High Absorption

Normal aggregates employed in concrete have absorption levels in the range of 0.2% to 4% for coarse aggregate and 0.2 to 2% for fine aggregate. However, some aggregates have absorption levels above these values. As the porosity of concrete is related to the porosity of both the cement paste and the aggregate and the carbonation rate is a function, among other things, of the porosity of the material, there is concern about the effect of this high porosity material in achieving good quality concrete from the durability point of view. Thus, the objective of this investigation was to study the carbonation rates of concrete specimens made with high-absorption limestone aggregate. Four different water/cement ratios were used, and cylindrical concrete specimens were exposed to accelerated carbonation. High porosity values were obtained for concrete specimens beyond the expected limits for durable concrete. However, carbonation coefficients related to normal quality concrete were obtained for the lowest water/cement ratio employed suggesting that durable concrete may be obtained with this material despite the high porosity.

Experimental Study on Compressive Strength of Recycled Aggregate Concrete

2008 ◽  
Vol 385-387 ◽  
pp. 381-384 ◽  
Author(s):  
Wei Wang ◽  
Hua Ling ◽  
Xiao Ni Wang ◽  
Tian Xia ◽  
Da Zhi Wang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Recycled Aggregate Concrete ◽  
Time Dependent ◽  
Recycled Aggregate ◽  
Experimental Investigations ◽  
Aggregate Concrete ◽  
Cement Ratio ◽  
Practical Engineering

With the increase in the use of recycled aggregate concrete (RAC), it is necessary to clearly understand its behavior and characteristics. In this paper, experimental study on compressive strength of RAC with same water/cement ratio is conducted. Firstly, influence of recycled coarse aggregate contents on cube compressive strength of RAC is studied. Secondly, experiment on time-dependent strength developing process of RAC is conducted with different solidification ages. Finally, based on above experimental investigations, empirical formula for compress strengths of RAC with different ages is presented. The result of this paper is helpful to theoretical analysis and practical engineering design of RAC structures.

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 Examining Polyethylene Terephthalate (PET) as Artificial Coarse Aggregates in Concrete

2020 ◽  
Vol 6 (12) ◽  
pp. 2416-2424
Author(s):  
Erniati Bachtiar ◽  
Mustaan Mustaan ◽  
Faris Jumawan ◽  
Meldawati Artayani ◽  
Tahang Tahang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Polyethylene Terephthalate ◽  
Coarse Aggregate ◽  
Fresh Concrete ◽  
Coarse Aggregates ◽  
Volume Weight ◽  
Concrete Mixtures ◽  
Strength Tests ◽  
Recycled Polyethylene

This study aims to examine the effect of recycled Polyethylene Terephthalate (PET) artificial aggregate as a substitute for coarse aggregate on the compressive strength and flexural strength, and the volume weight of the concrete. PET plastic waste is recycled by heating to a boiling point of approximately 300°C. There are five variations of concrete mixtures, defined the percentage of PET artificial aggregate to the total coarse aggregate, by 0, 25, 50, 75 and 100%. Tests carried out on fresh concrete mixtures are slump, bleeding, and segregation tests. Compressive and flexural strength tests proceeded based on ASTM 39/C39M-99 and ASTM C293-79 standards at the age of 28 days. The results showed that the use of PET artificial aggregate could improve the workability of the concrete mixture. The effect of PET artificial aggregate as a substitute for coarse aggregate on the compressive and flexural strength of concrete is considered very significant. The higher the percentage of PET plastic artificial aggregate, the lower the compressive and flexural strength, and the volume weight, of the concrete. Substitution of 25, 50, 75 and 100% of PET artificial aggregate gave decreases in compressive strength of 30.06, 32.39, 41.73 and 44.06% of the compressive strength of the standard concrete (18.20 MPa), respectively. The reductions in flexural strength were by respectively 19.03, 54.50, 53.95 and 61.00% of the standard concrete's flexural strength (3.59 MPa). The reductions in volume weight of concrete were by respectively 8.45, 17.71, 25.07 and 34.60% of the weight of the standard concrete volume of 2335.4 kg/m3 Doi: 10.28991/cej-2020-03091626 Full Text: PDF

scholarly journals Influence of Reduced Water Cement Ratio on Behaviour of Concrete Having Plastic Aggregate

2018 ◽  
Vol 4 (12) ◽  
pp. 2971 ◽  
Author(s):  
Saad Tayyab ◽  
Asad Ullah ◽  
Kamal Shah ◽  
Faial Mehmood ◽  
Akhtar Gul
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Stress Strain ◽  
Cement Ratio ◽  
Coarse Aggregates ◽  
Alternative Materials ◽  
Super Plasticizer ◽  
Strain Relationship ◽  
Natural Aggregates ◽  
Reduced Water

The production and use of plastic bottles is increasing tremendously with passing time. These plastic bottles become a problem when they are disposed as they are non-biodegradable. This means that the waste plastic, when dumped, does not decompose naturally and stays in the environment affecting the ecological system. The use of alternative aggregates like Plastic Coarse Aggregate (PCA) is a natural step in solving part of reduction of natural aggregates as well as to solve the issue discussed above. The researchers are trying from half a century to investigate the alternative materials to be replaced in concrete mixture in place of either aggregate or cement.  In this research, the concrete made from plastic waste as coarse aggregates were investigated for compressive strength and Stress-strain relationship. Plastic coarse aggregate have been replaced in place of natural coarse aggregate by different percentages with w/c 0.5, 0.4 and 0.3. The percentage replacement of plastic aggregate in place of mineral coarse aggregate was 25%, 30%, 35% and 40 %. Using Super-plasticizer Chemrite 520-BAS. OPC-53 grade cement was used. Total of forty five Cylinders were prepared based on different combination of Percentage of Plastic aggregate replaced and W/C as discussed above and checked for compressive strength and stress-strain relationship. The compressive strength increases by about 19.25% due to the decrease in W/C from 0.5 to 0.3 for plastic percentage addition of 40%.

scholarly journals Effect of Flyash Addition on Mechanical and Gamma Radiation Shielding Properties of Concrete

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Kanwaldeep Singh ◽  
Sukhpal Singh ◽  
Gurmel Singh
Keyword(s):  
Gamma Radiation ◽  
Attenuation Coefficient ◽  
Cement Content ◽  
Mass Attenuation Coefficient ◽  
Radiation Shielding ◽  
Mechanical Parameters ◽  
Cement Ratio ◽  
Concrete Mixtures ◽  
Water To Cement Ratio ◽  
Shielding Properties

Six concrete mixtures were prepared with 0%, 20%, 30%, 40%, 50%, and 60% of flyash replacing the cement content and having constant water to cement ratio. The testing specimens were casted and their mechanical parameters were tested experimentally in accordance with the Indian standards. Results of mechanical parameters show their improvement with age of the specimens and results of radiation parameters show no significant effect of flyash substitution on mass attenuation coefficient.

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