Effect of maximum grain size on value of modulus of rupture reactive powder concrete

2020 ◽  
Vol 26 (1) ◽  
pp. 1-8
Author(s):  
Widodo Kushartomo ◽  
Dewi Linggasari ◽  
Arianti Sutandi

Modulus of rupture (R) is a measurement of a tensile strengh of a concrete beam. The value of R is affected by the size of fine aggregat grain, the density of the concrete beam and the water-cement ratio. The unit of R is MPa expressing the tensile strength of the concrete beam without reinforcement to withstand a buckling failure. The distance between the supports of the concrete beam should not be less than three times of the height of the beam. In this research the size of the concrete beam speciment was 100 mm x 100 mm x 350 mm, the maximum fine aggregate size was varied (300 µm, 425 µm, and 600 µm) and the water-cement ratio was also varied (0.25, 0.22 and 0,20). All speciments were cured by steam curing and were tested after seven days. The results show that the larger the size of the fine aggregat grain and the higher the water-cement ratio, the smaller the R.

Author(s):  
Arianti Sutandi ◽  
Widodo Kushartomo

Kuat tekan beton merupakan faktor yang paling dominan untuk menentukan kualitas beton dibandingkan faktor lainnya. Kuat tekan beton atau mutu beton dipengaruhi oleh beberapa faktor diantaranya adalah perbandingan semen terhadap air (fa/s), kualitas material, perbandingan komposisi material dan sebagainya. Gradasi butiran agregat  juga merupakan salah satu faktor yang berperan penting untuk menentukan mutu beton. Agregat dengan ukuran butiran yang lebih halus dan bervariasi dapat memperkecil volume pori yang terbentuk, sehingga susunan butiran yang baik akan menghasilkan kepadatan tinggi dan porositas minimum. Pada penelitian ini dipelajarai pengaruh ukuran butiran maksimum agregat halus terhadap  kuat tekan reactive powder concrete. Benda uji dibuat dalam bentuk silinder dengan diameter 100,0 mm dan tinggi 200,0 mm. Ukuran diameter maksimum agergat halus dibuat dalam tiga jenis yaitu 300 µm. 425 µm, dan 600 µm. Seluruh benda uji dirawat dengan teknik perendaman selama 3 hari, dilanjutkan dengan steam curing pada temperature 90 oC – 95 oC selama 4 jam. Pengujian kuat tekan dilakukan pada umur 7 hari. Hasil pengujian menunjukkan terjadinya peningkatan kuat tekan recative powder concrete dengan bertambah kecilnya ukuran butiran maksimum agregat halus. The compressive strength of concrete is the most dominant factor to determine concrete quality compared to other factors. Concrete compressive strength and grade are influenced by several factors, including water cement ratio (fa/s), material quality, material composition, and others. Aggregate gradation is also one of the dominant factors that play an important role in determining the quality of concrete. Finer and varied aggregate size can reduce void volume, so that a good granular structure will produce high density and minimum porosity. In this research, the effect of maximum size of fine aggregate on the compressive strength of reactive powder concrete was studied. The specimens were made in cylindrical shapes with a diameter of 100.0 mm and a height of 200.0 mm. The maximum diameter size of fine agergate was varied in three types, 300 µm. 425 µm, and 600 µm. All specimens were treated with immersion technique for 3 days, followed by steam curing at 90 oC - 95 oC for 4 hours. Compressive strength testing was done at the age of 7 days. The test results showed that the increase of maximum fine aggregate size increase the compressive strength of reactive powder concrete.


2014 ◽  
Vol 597 ◽  
pp. 320-323 ◽  
Author(s):  
De Hong Wang ◽  
Yan Zhong Ju ◽  
Wen Zhong Zheng

Mechanical properties of reactive powder concrete (RPC) containing fly ash were investigated under different curing regimes (standard and steam curing) in this study. The experimental results indicate that, flexural strength of RPC increased considerably after steam curing, compared to the standard curing. Steam curing had no significant effect on compressive strength of RPC. Increasing the fly ash content improved the flexural strength of RPC under all curing regimes considerably. The compressive strength reached a maximum (103.8MPa) when the fly to ash and cement ratio is 0.3.


2010 ◽  
Vol 168-170 ◽  
pp. 1742-1748
Author(s):  
Yan Zhong Ju ◽  
Feng Wang ◽  
De Hong Wang

To study the mechanical properties of RPC performance and freeze-thaw resistance,through the experimental study discussed the water-cement ratio, silica fume cement ratio, steel fiber content, curing system and other factors on the mechanical properties of reactive powder concrete and anti-freezing properties. Research indicates that many factors in the RPC, the water cement ratio is the most important factor, followed by the silica fume cement ratio, finally the steel fiber content, and curing system for the growth of its early strength also have a greater role.


Author(s):  
Abrahão Bernardo Rohden ◽  
Ana Paula Kirchheim ◽  
Denise Dal Molin

abstract: Recent reports on reactive powder concrete address important aspects regarding its performance. Several techniques are used to improve the design of such concretes. Ultra-high compressive strengths have been reported with the application of pre-setting pressure and autoclave curing. The objective of this work is to evaluate the use of very fine quartz powder to replace fine aggregate, nanosilica, and inorganic pigments to optimize mechanical properties of reactive powder concrete. The experimental work was developed in three distinct phases. In the first phase, mix-proportions of reactive powder concrete have been developed, considering different maximum aggregate sizes (1.2, 0.6, 0.075, and 0.045 mm). In the second phase, the influence of nanosilica on the properties of reactive powder concrete was evaluated. In the third phase, the effect of the addition of yellow, green, orange, and blue inorganic pigments to the reactive powder concrete mix-design was evaluated. Results show that the maximum aggregate size influences the compressive strength of the reactive powder concrete. A decrease from 1.2 mm to 0.045 mm in the maximum aggregate size resulted in 156 MPa increase in the compressive strength. The type of pigment did not significantly influence the compressive strength of the reactive powder concrete. The mix-proportion that resulted in the highest compressive strength (310.7 MPa) was designed using yellow pigment.


2014 ◽  
Vol 1065-1069 ◽  
pp. 1833-1837
Author(s):  
Zheng Wang ◽  
Qi Fan Wang ◽  
Lin Zhang

Experimental study on the influence of the steel fiber types, content and water-cement ratio on the reactive powder concrete (RPC) performance is conducted. The results show the influence law that the 3 factors to compressive strength and shock-resistance of steel fiber RPC. In this sense, it is of vital importance to enhance structural strength, and to improve the anti-seismic and anti-detonating capacities of the key engineering in urban.


2015 ◽  
Vol 730 ◽  
pp. 11-14 ◽  
Author(s):  
Hai Long Zhang ◽  
Chang Chun Pei

By ANSYS finite element analysis we study the impact-span moment and deflection of high strength recycled concrete beam in state of initial cracking and yield with different water-cement ratio and recycled coarse aggregate replacement rate. The results showed that: 1With the increase of water-cement ratio and recycled coarse aggregate replacement rate, the deflection is on the rise. 2With the increase of recycled coarse aggregate replacement rate, the yield moment has a slight upward trend. And with the increase of water-cement ratio and recycled coarse aggregate replacement rate, the span deflection at the state of yield has a growing trend.


Author(s):  
Leo Gu Li ◽  
Jia-Jian Feng ◽  
Bo-Feng Xiao ◽  
Shao-Hua Chu ◽  
Albert Kwok Hung Kwan

AbstractPervious concrete is designed to be porous to allow permeation of water and air for combating the environmental and drainage problems arising from urbanization. However, despite extensive research, it is still not clear how best to design pervious concrete mixes to achieve good concurrent permeability-strength performance. In a previous study, the authors found that there is a necessity to distinguish between interconnected porosity and open porosity, and between unsubmerged permeability and submerged permeability. In this study, based on the thinking that fine aggregate may be added to reduce the paste volume provided the fine aggregate is fine enough to form a coherent mass with the paste, further research was conducted to develop the mortar type pervious concrete with reduced paste volume and investigate the roles of the mortar volume in porosity, permeability and strength. A new series of concrete mixes with varying mortar volume were tested and the results revealed that the interconnected porosity is the major factor determining the permeability while the open porosity and water/cement ratio are the major factors determining the strength. More importantly, the mortar volume plays a key role in each performance attribute.


2013 ◽  
Vol 448-453 ◽  
pp. 1316-1320
Author(s):  
Hai Chao Wang ◽  
Ke Qiu ◽  
Shu Ling Gao

Using orthogonal design method of four factors and three levels, make a mix ratio experiment on sleeper concrete of China's railway sleepers, used steam curing concrete early compressive strength (stripping strength) as evaluation index. Study on different experimental factors of water-cement ratio, sand ratio, fly ash and admixture differently influenced on the early strength of sleeper concrete and analyze the difference impact of each factor and level for the orthogonal experiment. The result shows that the admixture is the main factor for early strength of concrete, followed by fly ash, water-cement ratio and sand ratio. It can provide technical guidance for railway sleeper field and has practical value.


2018 ◽  
Vol 162 ◽  
pp. 02014
Author(s):  
Mazin Abdulrahman ◽  
Alyaa Al-Attar ◽  
Marwa Ahmad

Reactive Powder Concrete (RPC) is an ultra-high performance concrete which has superior mechanical and physical properties, and composed of cement and very fine powders such as quartz sand and silica fume with very low water/ binder ratio and Superplasticizer. Heat treatment is a well-known method that can further improve the performance of (RPC). The current research including an experimental study of the effect of different curing conditions on mechanical properties of reactive powder concrete (compressive strength, modulus of rupture and splitting tensile strength), the curing conditions includes three type of curing; immersion in water at temperature of 35 OC (which is considered as the reference-curing situation), immersion in water at temperature of 90 OC for 5 hours daily and curing with hot steam for 5 hours daily) until 28 days according to ASTM C684-99 [8]. This research includes also the study of effect of adding silica fume as percentage of cement weight on mechanical properties of reactive powder concrete for different percentage ratios (5%,10% and 15%). Super plasticizer is also used with ratio of (1.8%) by weight of cementitious material; constant water cement ratio (0.24) was used for all mixes. For each reactive concrete mix, it has been cast into a cubes of (150*150*150) (to conduct the compression test), a cylinders of 150mm diameter with 300mm height (to conduct split test) and prisms of (500*100*100)mm to conduct the modulus of rupture test. The results showed that the best method of curing (according to its enhancing the RPC mechanical properties) is the method of immersion in hot water at temperature 90 OC for the all silica fume percentages, and the best used silica fume percentage was (10%) for the all used curing methods.


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