Mechanical properties and durability of high-strength concrete containing macro-polymeric and polypropylene fibers with nano-silica and silica fume

2017 ◽  
Vol 132 ◽  
pp. 170-187 ◽  
Author(s):  
Saber Fallah ◽  
Mahdi Nematzadeh
Keyword(s):  
Mechanical Properties ◽  
Silica Fume ◽  
High Strength Concrete ◽  
High Strength ◽  
Polypropylene Fibers ◽  
Nano Silica ◽  
Strength Concrete

Analysis of Post-Combustion High-Strength Concrete Compressive Strength Using Polypropylene Fibers

2020 ◽  
Vol 26 (1) ◽  
pp. 118-127
Author(s):  
Teuku Budi Aulia ◽  
Muttaqin Muttaqin ◽  
Mochammad Afifuddin ◽  
Zahra Amalia
Keyword(s):  
Compressive Strength ◽  
Thermal Stress ◽  
Silica Fume ◽  
High Temperatures ◽  
High Strength Concrete ◽  
High Strength ◽  
Polypropylene Fibers ◽  
Concrete Compressive Strength ◽  
Strength Concrete ◽  
Maximum Value

High-strength concrete is vulnerable to high temperatures due to its high density. The use of polypropylene fibers could prevent structure explosion by forming canals due to melted fibers during fire, thus release its thermal stress. This study aims to determine the effect of polypropylene fibers on compressive strength of high-strength concrete after combustion at 400ºC for five hours. High-strength concrete was made by w/c-ratio 0.3 with cement amount 550 kg/m3 and added with silica fume 8% and superplasticizer 4% by cement weight. The variations of polypropylene fibers were 0%, 0.2% and 0.4% of concrete volume. The compression test was carried out on standard cylinders Ø15/30 cm of combustion and without combustion specimens at 7 and 28 days. The results showed that compressive strength of high-strength concretes without using polypropylene fibers decreased in post-combustion compared with specimens without combustion, i.e., 0.81% at 7 days and 23.42% at 28 days. Conversely, the use of polypropylene fibers can increase post-combustion compressive strength with a maximum value resulted in adding 0.2% which are 25.52% and 10.44% at 7 and 28 days respectively. It can be concluded that the use of polypropylene fibers is effective to prevent reduction of high-strength concrete compressive strength that are burned at high temperatures.

scholarly journals Effects of Plastic Waste on the Heat-Induced Spalling Performance and Mechanical Properties of High Strength Concrete

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3262
Author(s):  
Abrahão Bernardo Rohden ◽  
Jessica Regina Camilo ◽  
Rafaela Cristina Amaral ◽  
Estela Oliari Garcez ◽  
Mônica Regina Garcez
Keyword(s):  
Mechanical Properties ◽  
High Strength Concrete ◽  
Mechanical Performance ◽  
High Strength ◽  
Plastic Waste ◽  
Polypropylene Fibers ◽  
Strength Concrete ◽  
Polymer Melting ◽  
Computed Tomography Images ◽  
X Ray Computed

This paper investigates a potential application of hard-to-recycle plastic waste as polymeric addition in high strength concrete, with a focus on the potential to mitigate heat-induced concrete spalling and the consequent effects on the mechanical properties. The waste corresponds to soft and hard plastic, including household polymers vastly disposed of in landfills, although technically recyclable. Mechanical and physical properties, cracking, mass loss, and the occurrence of spalling were assessed in high strength concrete samples produced with either plastic waste or polypropylene fibers after 2-h exposure to 600 °C. The analysis was supported by Scanning Electron Microscopy and X-Ray Computed Tomography images. The plastic waste is composed of different polymers with a thermal degradation between 250 to 500 °C. Polypropylene (PP) fibers and plastic waste dispersed in concrete have proved to play an essential role in mitigating heat-induced concrete spalling, contributing to the release of internal pressure after the polymer melting. The different morphology of plastic waste and polypropylene fibers leads to distinct mechanisms of action. While the vapor pressure dissipation network originated by polypropylene fibers is related to the formation of continuous channels, the plastic waste seems to cause discontinuous reservoirs and fewer damages into the concrete matrix. The incorporation of plastic waste improved heat-induced concrete spalling performance. While 6 kg/m3 of plastic increased the mechanical performance after exposure to high temperature, the incorporation of 3 kg/m3 resulted in mechanical properties comparable to the reference concrete.

Investigation on Performance of Concrete Incorporating Silica Fume and Local UAE Materials

2019 ◽  
Vol 803 ◽  
pp. 222-227 ◽  
Author(s):  
Reem Sabouni ◽  
Hassan Raad Abdulhameed
Keyword(s):  
Mechanical Properties ◽  
Silica Fume ◽  
United Arab Emirates ◽  
High Strength Concrete ◽  
High Strength ◽  
Partial Replacement ◽  
Favorable Effect ◽  
Experimental Program ◽  
Strength Concrete ◽  
Local Materials

In an effort to reduce the amount of cement in the concrete industry and produce greener concrete, emphasis was put on using several industrial by-products such as silica fume, fly ash and slag as partial replacements for cement in concrete. Due to the enormous number of mega reinforced concrete projects constructed in the United Arab Emirates, it is considered to be one of the largest consumers of high strength concrete in the region. On the other hand, only limited research has been done on high strength concrete incorporating local materials in the UAE. The main objective of this research is to conduct an investigation on the performance of high strength concrete containing silica fume as partial replacement of ordinary Portland cement incorporating superplasticizers and local UAE materials by studying its mechanical properties and durability. The experimental program involved two groups: The first group had a water-to-binder material ratio (w/b) of 0.4, whereas, the second group had w/b = 0.3. For both groups the silica fume replacement percentages were 0 (control mix) 5, 7.5, 10, 12.5, and 15 percent. The mechanical properties were tested at 7, 28, and 91 days and the durability tests were performed at 28 days. The results were compared to the control mix and they showed that for all the curing ages studied the use of silica fume as partial replacement of OPC has favorable effect on the compressive strength values and the optimum replacement ratios of silica fume for the tested specimens are found to be at 12.5% and 10% replacement for the w/b ratios of 0.3 and 0.4, respectively. For all the four performed durability tests the replacement of the OPC with silica fume is found to have favorable results and the higher the silica fume percentage replacement of OPC the more favorable the results are. The detailed description of the used mixes and the main conclusions drawn from this research are presented in this paper

scholarly journals Investigation of Using Nano-silica, Silica Fume and Fly Ash in High Strength Concrete

2020 ◽  
Vol 43 (3) ◽  
pp. 211-221
Author(s):  
Mohamed Fahmy ◽  
Mohamed Abu El-Hassan ◽  
Gamal Kamh ◽  
Alaa Bashandy
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
High Strength Concrete ◽  
High Strength ◽  
Nano Silica ◽  
Strength Concrete

scholarly journals Evaluation of Mix Proportions and Mechanical Properties of Normal and High-Strength Fibers Concrete

2019 ◽  
Vol 9 (2) ◽  
pp. 202-207
Author(s):  
Imad R. Mustafa ◽  
Omar Q. Aziz
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Silica Fume ◽  
High Strength Concrete ◽  
Steel Fiber ◽  
High Strength ◽  
Splitting Tensile Strength ◽  
Strength Concrete

An experimental program is carried out to evaluate the mix design and mechanical properties of normal strength concrete (NSC) grade 40 MPa and high-strength concrete grade 60 and 80 MPa. The study investigates using silica fume to produce high-strength concrete grade 80 MPa and highlights the influence of adding steel fiber on the mechanical properties of normal and high-strength concrete. For NSC, the compressive strength is found at 7 and 28 days. While for higher strength concrete, the compressive strength is determined at 7, 28, and 56 days. The splitting tensile strength and flexural strength is determined at 28 days. Based on results, the specimens with 14% silica fume are higher compressive strength than the specimens with 10% silica fume by 21.8%. The presence of steel fiber increased the compressive strength of normal and high-strength concrete at 7, 28, and 56 days curing ages with different percentage and the steel fiber has an important role in increasing the splitting tensile strength and flexural strength of normal and high-strength concrete.

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