scholarly journals Development of Water Retentive and Thermal Resistant Cement Concrete and Cooling Effects Evaluation

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6141
Author(s):  
Xiaowei Wang ◽  
Xinyu Hu ◽  
Xiaoping Ji ◽  
Bo Chen ◽  
Hongqing Chen
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Mechanical Performance ◽  
Water Retention Capacity ◽  
Cement Concrete ◽  
Retention Capacity ◽  
Monitoring Test ◽  
Stone Mastic Asphalt ◽  
Cooling Effects ◽  
Refractory Aggregate

The high pavement temperature plays an important role in the development of urban heat island (UHI) in summer. The objective of this study was to develop water retentive and thermal resistant cement concrete (WTCC) to enhance the pavement cooling effects. The WTCC was prepared by combining a water retentive material and a high aluminum refractory aggregate (RA) with porous cement concrete (PCC). Water retention capacity test, fluidity test, and compressive strength test were used to determine the composition ratio of the water retentive material. Mechanical performance and cooling effects of WTCC were evaluated by compressive and flexural strength tests and temperature monitoring test. The mass ratios of fly ash, silica fume, cement, and water in the water retentive material were determined as 65:35:15:63.9. The compressive strength and the flexural strength of WTCC after 28 days curing were 30.4 MPa and 4.6 MPa, respectively. Compared with stone mastic asphalt (SMA) mixture, PCC, and water retentive cement concrete (WCC), surface temperature of WTCC decreased by 11.4 °C, 5.5 °C, and 4.1 °C, respectively, and the internal temperatures of WTCC decreased by 10.3 °C, 6.1 °C, and 4.6 °C, respectively. The water retentive material has benefits of strength improvements and temperature reduction for WTCC. Based on the results, WTCC proved to have superior cooling effects and the potential to efficiently mitigate the UHI effects and be used in medium traffic roads.

scholarly journals Influence of Glass Fibers on Mechanical Properties of Concrete with Recycled Coarse Aggregates

2019 ◽  
Vol 5 (5) ◽  
pp. 1007-1019 ◽  
Author(s):  
Babar Ali ◽  
Liaqat Ali Qureshi ◽  
Ali Raza ◽  
Muhammad Asad Nawaz ◽  
Safi Ur Rehman ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Glass Fibers ◽  
Construction Material ◽  
Concrete Compressive Strength ◽  
Coarse Aggregates ◽  
Highly Sensitive

Despite plain cement concrete presenting inferior performance in tension and adverse environmental impacts, it is the most widely used construction material in the world. Consumption of fibers and recycled coarse aggregates (RCA) can add ductility and sustainability to concrete. In this research, two mix series (100%NCA, and 100%RCA) were prepared using four different dosages of GF (0%GF, 0.25%GF, 0.5%GF, and 0.75%GF by volume fraction).  Mechanical properties namely compressive strength, splitting tensile strength, and flexural strength of each concrete mixture was evaluated at the age of 28 days. The results of testing indicated that the addition of GF was very useful in enhancing the split tensile and flexural strength of both RCA and NCA concrete. Compressive strength was not highly sensitive to the addition of GF. The loss in strength that occurred due to the incorporation of RCA was reduced to a large extent upon the inclusion of GF. GF caused significant improvements in the split tensile and flexural strength of RCA concrete. Optimum dosage of GF was determined to be 0.25% for NCA, and 0.5% for RCA concrete respectively, based on the results of combined mechanical performance (MP).

Influence of Wollastonite or Plant Fiber on Performance of Autoclaved Cement Concrete

2011 ◽  
Vol 99-100 ◽  
pp. 692-695
Author(s):  
Tie Quan Ni ◽  
Li Zhang ◽  
Bing Yuan
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Bending Strength ◽  
Composition Analysis ◽  
X Ray Diffraction ◽  
Cement Concrete ◽  
Plant Fiber ◽  
X Ray ◽  
Strength Change ◽  
Chemical Composition Analysis

The influence of wollastonite or plant fiber on the property of autoclaved cement concrete is studied by chemical composition analysis, X-ray diffraction analysis, scanning electron microscopy and energy spectrum analysis. The results showed that the two fibers were benefit to bending strength of autoclaved cement concrete. The suitable content of wollastonite was about 15% of cement mass, and the increased amplitude of flexural strength was more than 30% and the compressive strength slightly increased for autoclaved cement concrete admixed wollastonite. The optimal content of plant fiber was about 1.5% of cement mass, the increased amplitude of the flexural strength was more than 20%, and the compressive strength change of autoclaved cement concrete was not significant for autoclaved cement concrete admixed plant fiber.

Research on the Main Mechanical Capability of Steel Fibers Concrete of Deck Pavement

2011 ◽  
Vol 374-377 ◽  
pp. 1619-1622
Author(s):  
Ling Zhang ◽  
Zhi Qiang Shi
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Service Life ◽  
Flexural Strength ◽  
Steel Fiber ◽  
Mechanical Performance ◽  
Volume Ratio ◽  
Steel Fibers ◽  
Fiber Types ◽  
Splitting Strength

In this article, based on a certain actual project, the main physical and mechanical performance including compressive strength, splitting strength, flexural strength and shear strength are studied in detail through the experiments. Different fiber types and volume ratio are chosen in the experiments for the purpose of determining the best quantities and types of steel fiber in concrete to lengthen the service life of deck pavements. It is showed that the research has some referential value for similar projects.

scholarly journals The Effect of Sisal Juice Extract Admixture on Compressive and Flexural Strength of Cement Concrete

2021 ◽  
Vol 11 (2) ◽  
pp. 7041-7046
Author(s):  
M. O. Eloget ◽  
S. O. Abuodha ◽  
M. M. O. Winja
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Cementitious Materials ◽  
Strength Development ◽  
Concrete Durability ◽  
Flexural Test ◽  
Concrete Compressive Strength ◽  
Cement Concrete ◽  
Shrinkage Cracking ◽  
Lower Permeability

The characteristics of concrete are influenced by the ratio of water to cementitious materials (w/c) used in the mixture. An increase in paste quality will yield higher compressive and flexural strength, lower permeability, increased resistance to weathering, improve the bond between concrete and reinforcement, reduced volume change from drying and wetting, and reduced shrinkage cracking tendencies. Admixtures are used to improve the properties of concrete or mortar. The current study investigates the effect of Sisal Juice Extract (SJE) as an admixture on concrete durability. SJE contains unrefined minerals which can be used as organic retarders to increase the rate of strength development at an early age. A total of 84 concrete cubes were produced in 7 sets of 12 samples each. One set was the control mix which had zero SJE content. The remaining sets had varying dosages of SJ namely 5%, 10%, 15%, 20%, 25%, and 30%. Twelve beam specimens were also cast and subjected to the three-point flexural test. To establish the effect on strength of concrete, compressive strength was tested at 7, 14, 28, and 56 days while flexural strength was tested at 28 days. The highest compressive strength was achieved at 5% dosage beyond which a decrease in strength occurred for all the higher dosages.

Fine Grain Portland Cement Concrete with Complex Nanodisperse Admixture for Structure Rehabilitating

2015 ◽  
Vol 1122 ◽  
pp. 105-110
Author(s):  
Galina D. Fedorova ◽  
Gregory N. Alexandrov ◽  
Grigory I. Yakovlev ◽  
Irina S. Polyanskikh ◽  
Igor A. Pudov
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Portland Cement ◽  
Concrete Structures ◽  
Working Time ◽  
Strength Characteristics ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Fine Grain

The influence of new complex nanodisperse admixture on structure and strength characteristics of fine grain concrete used in rehabilitation of damaged concrete structures has been studied. Concrete without the admixture is more susceptible to cracking than concrete with the complex admixture, thus increasing the working time of structures. At the age of 28 days the compressive strength of fine grain concrete with the admixture reaches 52,35 MPa, the flexural strength is 5,2 MPa. The strength characteristics of concrete increased by 15%.

scholarly journals Impact of Incorporating Metakaolin on the Mechanical Performance of High Grade Concrete

2019 ◽  
Vol 8 (3) ◽  
pp. 7736-7739 ◽  
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Mechanical Performance ◽  
Strength Test ◽  
Strength Development ◽  
High Grade ◽  
Test Results ◽  
Normal Concrete ◽  
Split Tensile Strength ◽  
Compressive Strength Test

This paper studies the effect of incorporating metakaolin on the mechanical properties of high grade concrete. Three different metakaolins calcined at different temperature and durations were used to make concrete specimens. Three different concrete mixtures were characterized using 20% metakaolin in place of cement. A normal concrete mix was also made for comparison purpose. The compressive strength test, split tensile test and flexural strength tests were conducted on the specimens. The compressive strength test results showed that all the metakaolin incorporated concrete specimens exhibited higher compressive strength and performed better than normal concrete at all the days of curing. The rate of strength development of all the mixes was also studied. The study revealed that all the three different metakaolin incorporated mixtures had different rate of strength development for all the days of hydration (3, 7,14, 28, 56 and 90), indicating that all the metakaolins possessed different rate of pozzolanic reactivity. Further, from the analysis of the test results, it was concluded that the variation in the rate of strength development is due to the differences in the temperature and duration at which they were manufactured. The results of split tensile strength test and the flexural strength test conducted on the specimens, supported the conclusions drawn from the results of compressive strength test. The paper also discusses, the rate of development of compressive strength and the pozzolanic behaviour of the metakaolins in light of their parameters of calcination and physical properties such as amorphousness and particle size. This paper has been written with a view to make the potential of metakaolin available to the construction industry at large

scholarly journals Influence of Fibre Length on the Behaviour of Polypropylene Fibre Reinforced Cement Concrete

2018 ◽  
Vol 4 (9) ◽  
pp. 2124-2131 ◽  
Author(s):  
Imtiaz Ahmed Memon ◽  
Ashfaque Ahmed Jhatial ◽  
Samiullah Sohu ◽  
Muhammad Tahir Lakhiar ◽  
Zahid Hussain Khaskheli
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Control Sample ◽  
Fibre Length ◽  
Reinforce Concrete ◽  
Polypropylene Fibre ◽  
Cement Concrete ◽  
Reinforced Cement ◽  
Increased Strength ◽  
Vast Range

Concrete being a mixture of cement, aggregates (fine and coarse) and water, can be used in vast range of applications. It has excellent durability and availability which are its main advantages. Though, concrete is strong in compression it is comparatively weak in tensile loading. Over the years various materials have been used to reinforce concrete to withstand the tensile stresses. Polypropylene fibre is one such fibre which comes in varied sizes, is nowadays being utilized to reinforce concrete. In this study, three PP fibres were used at 0.20%, 0.25% and 0.30% content by weight. The flexural and compressive strengths were determined. Based on the results, it was observed with increase in size of fibre the compressive strength decreased significantly though it was still higher than the controlled sample. The length of PP fibres had significant effect on the compressive strength and flexural strength of concrete. Short PP fibres showed relatively higher compressive strength but lower flexural strength when higher fibre content is used, while long PP fibres achieved lower compressive strength but higher flexural strength than shorter PP fibres. The optimum dosage for both PP fibre sizes was 0.25% at which it achieved increased strength as compared to control sample.

The Effect of Integral Waterproof Admixture on some Mechanical Properties of Concrete, Absorption and Sulfate Attack Using Different Mix Proportions

2021 ◽  
Vol 895 ◽  
pp. 88-96
Author(s):  
Qusay A. Jabal ◽  
Mohammed Riyadh Al-Dikheeli
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Sulfate Attack ◽  
Cement Concrete ◽  
Normal Concrete

. This investigation aims to improving mechanical properties of normal concrete such as compressive strength, tensile strength, and flexural strength by using integral waterproof admixture (IWP) and also decreasing absorption of concrete, using different mix proportions of concrete, study shows a good increment of compressive strength for all mixes by using integral waterproof and also increasing the flexural and tensile strengths. The study contains also a sulfate attack study on normal mixes and integral waterproof mixes. Different percentages of IWP used in the study containing 0.0%, 1% ,1.5% and 2% for each 100 kg cement. Concrete mixes with 2% IWP admixture and 1:1:1.5 mix proportions give the highest values of compressive, tensile, and flexural strength in the study. compressive strength improved from 33.6MPa for reference 1:1:1.5 mix to 39.8 MPa by using IWP, also less absorption concrete obtained, the absorption was lowered from 3.5% to 1.7%, also deterioration in strength due to sulfate attack was small compared with reference mixes, same to other mixes 1:2:4, 1:1.5:3 that also improved by IWP admixture and lead to increasing mechanical properties and reducing absorption and sulfate attack.

Influence of the Kind and the Shape of Insulating Materials on the Mechanical Properties of the Composites Plaster- Granular Cork and Plaster- Fiber Alpha

2021 ◽  
Vol 886 ◽  
pp. 241-255
Author(s):  
Youssef Maaloufa ◽  
Soumia Mounir ◽  
Khabbazi Abdelhamid ◽  
Khalid El Harrouni
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Thermal Performance ◽  
Mechanical Characterization ◽  
Mechanical Performance ◽  
Building Envelope ◽  
Insulating Materials

The objective of our work is to study the influence of nature and the shape of the insulating materials on the mechanical performance of composites based on plaster. The study aims to increase the thermal performance of the building envelope and the same time maintains sufficient mechanical properties of the composites studied. Plaster was combined with two additives (alpha fiber and granular cork). A physical and mechanical characterization of the composites plaster-fiber alpha and plaster-cork was carried on. Authors obtained an important gain in term of lightness 27 % concerning the composite plaster-fiber alpha, however for the composite plaster-cork, the value is 34 %. Concerning the mechanical properties, authors found a decrease in flexural strength of 60 % for the plaster-cork, and an increase of 33 % for the plaster-alpha fiber. For the compressive strength, a reduce of 87 % for the plaster-alpha fiber and 80% for the plaster-cork was observed. Those finding are justified by the scanning microscopic electron tests which show the distribution of the two insulators and adhesion within the plaster matrix.

Effect of Rubber Powder Dosage on Performance of Cement Concrete

2014 ◽  
Vol 919-921 ◽  
pp. 1908-1911
Author(s):  
Yan Cong Zhang ◽  
Shao Wen Liu ◽  
Ling Ling Gao
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Linear Growth ◽  
Cement Concrete ◽  
Growth Trend ◽  
Cement Ratio ◽  
Rubber Powder ◽  
Water Cement Ratio ◽  
Fine Aggregates ◽  
Rubber Cement

A number of rubber cement concrete specimens that rubber powder dosage different were obtained using same cement, water and fine aggregates, by adjusting the dosage of rubber powder. Then it was used to research the influence of rubber powder dosage on performance of cement concrete by measuring its liquidity, strength and toughness. The results show that: when water-cement ratio was equal and rubber powder replacing the same volume sand, the fluidity of cement concrete almost linear increased with rubber powder dosage increasing. With dosage of rubber powder increasing, compressive strength and flexural strength reduced, but toughness linear growth trend when dosage of rubber powder less 30%.

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