Effect of Aggregate Packing on Strength of Reactive Powder Concrete: Modeling and Experimental Evaluation

2020 ◽  
Vol 998 ◽  
pp. 299-304
Author(s):  
Umut Bektimirova ◽  
Islam Mukhammedrakhym ◽  
Chang Seon Shon ◽  
Dichuan Zhang ◽  
Jong Kim
Keyword(s):  
Compressive Strength ◽  
Experimental Verification ◽  
Experimental Evaluation ◽  
Reactive Powder Concrete ◽  
Strength Development ◽  
Model Calculations ◽  
Fraction Size ◽  
Aggregate Packing ◽  
Reactive Powder ◽  
Test Result

This research investigates the effects of aggregate packing degree on the strength of Reactive Powder Concrete (RPC) mixtures on the basis of the Toufar model. To optimize the packing degree of sand for strength development of RPC, various sand blends with the combination of different fraction size were used. In addition, 10 different blends that showed best packing degree were chosen to investigate the compressive strength of RPC. It was found that experimental verification results conform to Toufar model calculations. The test result shows that packing degree had a significant effect on the strength of RPC: Mixtures with higher packing degree can achieve higher compressive strength. Furthermore, Results indicate the Toufar model can predict packing degree of aggregate blends.

scholarly journals Effect of silica fume/binder ratio on compressive strength development of reactive powder concrete under two curing systems

2018 ◽  
Vol 162 ◽  
pp. 02022 ◽  
Author(s):  
Mohammed Abed ◽  
Mohammed Nasr ◽  
Zaid Hasan
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
Hot Water ◽  
Reactive Powder Concrete ◽  
Strength Development ◽  
Accelerated Curing ◽  
Binder Ratio ◽  
Compressive Strength Development ◽  
Reactive Powder ◽  
Curing Systems

This paper aims to investigate the influence of Silica fume proportion ratio in respect to the total amount of binder on compressive strength of reactive powder concrete cured in two curing systems. Four ratios of Silica fume (0%, 15%, 25% and 35%) as replacement of cement weight were considered. After de-molding, two curing systems were used: the first included immersing the cubic specimens in water at 24 ± 2°C until the test. In the second, the specimens were immersed in hot water at 105 ± 5°C (accelerated curing) for 48 hours, then in water at 24 ± 2°C until the test. The results show that mix which contains 25% Silica fume imparts more enhancement on compressive strength as compared to the control mix. Also, it was found that the second system of curing has more influence on compressive strength development than the first one, especially at earlier ages.

Quantitative Study of Hydration of C3S and C2S in the Reactive Powder Concrete together with its Strength Development

2019 ◽  
Vol 889 ◽  
pp. 294-303
Author(s):  
Quoc Si Bach
Keyword(s):  
Heat Flux ◽  
Compressive Strength ◽  
Portland Cement ◽  
Quantitative Study ◽  
Isothermal Calorimetry ◽  
Pozzolanic Reaction ◽  
Reactive Powder Concrete ◽  
Strength Development ◽  
Compressive Strength Development ◽  
Reactive Powder

The compressive strength development always go along with the microstructure development in concrete through the process of cement hydration. In the hydrated products of cement, calcium silicate hydrate (C-S-H) forms a network of nanoparticles so C-S-H gel is the main compound giving compressive strength of concrete. As we know that C-S-H gel produced by the reactions with water of two main minerals in cement such as Tricalcium Silicate () and Dicalcium Silicate (). In addition, the increase of C-S-H content in concrete due to the pozzolanic reaction of the pozzolan with calcium hydroxide (CH). With the aim of this research is quantitative study of hydration of and in the Reactive Powder Concrete (RPC) together with its compressive strength development, three concrete formulas were estimated in this study which made from three different types of cement ownership different mineral compositions content were tested on compressive strength and on heat flux emitted from hydration process by isothermal calorimetry. The purpose of measuring heat flux emitted from chemical reaction process in concrete is to verify the hydration kinetic model for portland cement containing the silica fume. Basing on this simulation program, the amount of C-S-H gel in concrete is calculated. The research results showed that the the C-S-H content formed in binder paste of RPC is proportional to compressive strength development. The (Ordinary Portland Cement) OPC with higher content have compressive strength development earlier.

Tests on Mechanical Properties and Anti-Penetration Performance of Steel-Fiber Reactive Powder Concrete

2013 ◽  
Vol 671-674 ◽  
pp. 1761-1765
Author(s):  
Yong Liu ◽  
Chun Ming Song ◽  
Song Lin Yue
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Steel Fiber ◽  
Reactive Powder Concrete ◽  
Calculation Results ◽  
Reactive Powder ◽  
Penetration Tests

In order to get mechanical properties ,some RPC samples with 5% steel fiber are tested, many groups data were obtained such as compressive strength, shear strength and fracture toughness. And a group of tests on RPC with 5% steel-fiber under penetration were also conducted to validate the performance to impact. The penetration tests are carried out by the semi-AP projectiles with the diameter of 57 mm and earth penetrators with the diameter of 80 mm, and velocities of the two kinds of projectiles are 300～600 m/s and 800～900 m/s, respectively. By contrast between the experimental data and the calculation results of C30 reinforced concrete by using experiential formula under penetration, it shows that the resistance of steel-fiber RPC to penetration is 3 times as that of general C30 reinforced concrete.

scholarly journals A Study on Optimum Mixture Ratio of Reactive Powder Concrete

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Mingyang Chen ◽  
Wenzhong Zheng
Keyword(s):  
Compressive Strength ◽  
Steel Fiber ◽  
Raw Materials ◽  
Reactive Powder Concrete ◽  
Mixture Ratio ◽  
Curing Methods ◽  
Main Components ◽  
Cement Strength ◽  
Reactive Powder ◽  
Design Factors

To optimize the main components of reactive powder concrete (RPC) for various curing methods, based on the fluidity and compressive strength, an inclusive experimental research is conducted on 58 different mixture ratios. The results indicate that owing to the increase of the cement strength, the RPC fluidity decreases and the cement strength is not proportional to the compressive strength. The addition of the fly ash and the nano-microbead is an effective way to improve the fluidity, and it is required at the low W/B ratio. However, the influence of the SF grade on the strength and fluidity is almost negligible. By considering the fluidity, strength, and economy of RPC as crucial design factors, SF90 is suggested. The contribution of the steel fiber to the compressive strength cannot be ignored. The upper envelope value of the steel fibers is required for the structure to resist appropriately against the fire. According to the test results, the mixture ratio formula is proposed through considering the characters of different compositions and curing methods. The strength coefficient k1 is introduced to verify the influence of the steel fiber content, and the parameters fb, αa, and αb in the formula are reevaluated. A reasonably good agreement between the calculated strength and those obtained from the tests is reported, except for the case of W/B = 0.16 with P.O.52.5 cement. The basic steps for preparations of different RPC strengths are given, which provide a valuable reference to choose appropriate raw materials and mixture ratio design for different strength values.

scholarly journals Influence of Partial Replacement of Micro-Silica by Fly-Ash on Strength Properties of Reactive Powder Concrete

2020 ◽  
Vol 9 (3) ◽  
pp. 2932-2937
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Mechanical Performance ◽  
Cementitious Materials ◽  
Partial Replacement ◽  
Reactive Powder Concrete ◽  
Experimental Investigations ◽  
Reactive Powder ◽  
Micro Silica

Reactive powder concrete (RPC) is the ultra-high strength concrete made by cementitious materials like silica fumes, cement etc. The coarse aggregates are completely replaced by quartz sand. Steel fibers which are optional are added to enhance the ductility. Market survey has shown that micro-silica is not so easily available and relatively costly. Therefore an attempt is made to experimentally investigate the reduction of micro-silica content by replacing it with fly-ash and mechanical properties of modified RPC are investigated. Experimental investigations show that compressive strength decreases gradually with addition of the fly ash. With 10 per cent replacement of micro silica, the flexural and tensile strength showed 40 and 46 per cent increase in the respective strength, though the decrease in the compressive strength was observed to be about 20 per cent. For further percentage of replacement, there was substantial drop in compressive, flexural as well as tensile strength. The experimental results thereby indicates that utilisation of fly-ash as a partial replacement to micro silica up to 10 per cent in RPC is feasible and shows quite acceptable mechanical performance with the advantage of utilisation of fly-ash in replacement of micro-silica.

scholarly journals Mechanical Testing of Composite Steel and Reactive Powder Concrete Structural Element

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3954
Author(s):  
Jan Bujnak ◽  
Peter Michalek ◽  
Frantisek Bahleda ◽  
Stefania Grzeszczyk ◽  
Aneta Matuszek-Chmurowska ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Composite Structures ◽  
Numerical Models ◽  
Concrete Slab ◽  
Initial Study ◽  
Cementitious Materials ◽  
Mechanical Tests ◽  
Reactive Powder Concrete ◽  
Structural Element ◽  
Reactive Powder

Reactive powder concrete (RPC), typically with higher compressive strength, is particularly attractive to structural engineers to apply them in infrastructures for enhancing their resistance under severe environments and loads. The main objective of the initial study presented in the paper was to investigate the behavior of two types of these new cementitious materials differing in the nature of microfibers. The RPC mixes were reinforced with steel and then with basalt microfibers. To evaluate the structural performance of developed unconventional materials, properties were investigated experimentally and compared with the control normal concrete mix. Mechanical tests indicated that dispersing fine fibers for making RPC, a mean compressive strength of 198.3 MPa and flexural strength 52.6 MPa or 23.2 MPa, respectively, were developed after 28 days of standard curing at ambient temperatures. In composite structures consisting of steel girders and a concrete slab, it is necessary to prevent the relative slip at the steel and concrete interface using shear connectors. The very high RPC strength enabled a material saving, weight-reduced application of precast construction, and particularly effective joint to steel beams. The investigation of such shear connection efficiency, in the case of the higher strength concrete deck, using standard push-out test specimens was executed. Finite element numerical models were developed. The outputs of the studies are presented in the paper.

scholarly journals Effect of Mix Proportion Parameters on Behaviors of Basalt Fiber RPC Based on Box-Behnken Model

2019 ◽  
Vol 9 (10) ◽  
pp. 2031 ◽  
Author(s):  
Hanbing Liu ◽  
Shiqi Liu ◽  
Shurong Wang ◽  
Xin Gao ◽  
Yafeng Gong
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Basalt Fiber ◽  
Fiber Content ◽  
Reactive Powder Concrete ◽  
Basalt Fibers ◽  
Factors Affecting ◽  
Remarkable Effect ◽  
Mix Proportion ◽  
Reactive Powder

Basalt fibers are widely used in the modification of concrete materials due to its excellent mechanical properties and corrosion resistance. In this study, the basalt fibers were used to modify reactive powder concrete (RPC). The effect of four mix proportion parameters on the working and mechanical properties of basalt fiber reactive powder concrete (BFRPC) was evaluated by the response surface methodology (RSM). The fluidity, flexural and compressive strength were tested and evaluated. A statistically experimental model indicated that D (the silica fume to cement ratio) was the key of interactions between factors, affecting other factors and controlling properties of BFRPC. The increase in basalt fiber content had a remarkable effect on increasing the flexural and compressive strength when D = 0.2. The addition of basalt fiber obviously improved the mechanical properties of RPC. While when D = 0.4, the decrease of fiber content and the increase of quartz sand content could increase the compressive strength.

Research on Impact Behavior of Reactive Powder Concrete

2010 ◽  
Vol 150-151 ◽  
pp. 779-782
Author(s):  
Qing Xin Zhao ◽  
Zhao Yang Liu ◽  
Jin Rui Zhang ◽  
Ran Ran Zhao
Keyword(s):  
Compressive Strength ◽  
Impact Toughness ◽  
Flexural Strength ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Impact Behavior ◽  
Reactive Powder Concrete ◽  
Flexural Toughness ◽  
Reactive Powder ◽  
The Impact

By means of the three-point bending impact equipment, with the measurement of ultrasonic velocity, the impact behavior and damage evolution of reactive powder concrete (RPC) with 0, 1%, 2% and 3% volume fraction of steel fiber were tested. The results showed that steel fiber significantly improved the compressive strength, flexural strength, flexural toughness and impact toughness of RPC matrix. The compressive strength, flexural strength, flexural toughness of RPC with 3% steel fiber increased by 40.1%, 102.1%, and 37.4 times than that of plain concrete, respectively, and simultaneously, the impact toughness of RPC with 3% steel fiber was 93.2 times higher than that with 1% steel fiber. RPC with 2% and 3% steel fiber dosage both had relatively high compressive strength, flexural strength and flexural toughness; however, compared with the sample with 2% steel fiber dosage, the impact toughness of RPC with 3% steel fiber dosage increased by more than 10 times. Therefore, taking economy and applicability into consideration, if we mainly emphasis on the compressive strength, flexural strength and flexural toughness, RPC with 2% steel fiber is optimal. While if impact toughness is critical, RPC with 3% steel fiber would be the best choice.

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