scholarly journals Time-Varying Compressive Strength Model of Aeolian Sand Concrete considering the Harmful Pore Ratio Variation and Heterogeneous Nucleation Effect

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Yugen Li ◽  
Huimei Zhang ◽  
Xiaoyu Liu ◽  
Guangxiu Liu ◽  
Dawei Hu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Heterogeneous Nucleation ◽  
American Concrete Institute ◽  
Time Varying ◽  
Strength Model ◽  
Aeolian Sand ◽  
Mu Us Desert ◽  
Nucleation Effect ◽  
Influence Mechanism ◽  
Ratio Variation

The aim of this study was to analyze the influence mechanism of aeolian sand on the mechanical property of concrete and establish the time-varying compressive strength model. Test studies on the development of concrete’s compressive strength with aeolian sand from the Mu Us Desert were carried out. Influence mechanism of aeolian sand on the strength of concrete was revealed by using the nuclear magnetic resonance (NMR) to analyze the pore ratio and structures of aeolian sand concrete (ASC) and using the X-ray single crystal diffraction (XRD) to calculate the relative contents of hydration products semiquantitatively. Results show that the strength first increases and then decreases with the increase of aeolian sand content, where 20% was the best replacement ratio. With less than 20% content, it promoted the strength by changing the pore structure of concrete and accelerating the cement hydration speed based on its filling effect and chemical activity; when the content was more than 20%, it led to a decrease of strength because of an increase of harmful pore ratio and a weakening of the interface transition zone (ITZ), where the stress concentration and damage when loading are easier to occur. At last, a time-varying compressive strength model of ASC considering the harmful pore ratio variation and heterogeneous nucleation effect was established based on the discussion, published date, and American Concrete Institute (ACI) model, which agrees well with the experimental results and can easily predict the strength of concrete.

scholarly journals Optimised Mix Design for Normal Strength and High Performance Concrete Using Particle Packing Method

2011 ◽  
Vol 57 (4) ◽  
pp. 357-371 ◽  
Author(s):  
S. Gopinath ◽  
A. Ramachandra Murthy ◽  
D. Ramya ◽  
Nagesh R. Iyer
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
American Concrete Institute ◽  
Particle Packing ◽  
Mix Design ◽  
Concrete Compressive Strength ◽  
Normal Strength Concrete ◽  
Normal Strength ◽  
Packing Method

Abstract This paper presents the details of optimized mix design for normal strength and high performance concrete using particle packing method. A critical review of mix design methods have been carried out for normal strength concrete using American Concrete Institute (ACI) and Bureau of Indian Standards (BIS) methods highlighting the similarities and differences towards attaining a particular design compressive strength. Mix design for M30 and M40 grades of concrete have been carried out using ACI, BIS and particle packing methods. Optimization of concrete mix has been carried out by means of particle packing method using EMMA software, which employs modified Anderson curve to adjust the main proportions. Compressive strength is evaluated for the adjusted proportions and it is observed that the mixes designed by particle packing method estimates compressive strength closer to design compressive strength. Further, particle packing method has been employed to optimize the ingredients of high performance concrete and experiments have been carried out to check the design adequacy of the desired concrete compressive strength.

scholarly journals Mechanical Properties and Environmental Evaluation of Ultra-High-Performance Concrete with Aeolian Sand

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3148 ◽  
Author(s):  
Hongyan Chu ◽  
Fengjuan Wang ◽  
Liguo Wang ◽  
Taotao Feng ◽  
Danqian Wang
Keyword(s):  
Compressive Strength ◽  
Environmental Impact ◽  
Young’S Modulus ◽  
High Performance ◽  
High Performance Concrete ◽  
Young's Modulus ◽  
Ultra High Performance Concrete ◽  
Aeolian Sand ◽  
Binder Ratio ◽  
Water Binder Ratio

Ultra-high-performance concrete (UHPC) has received increasing attention in recent years due to its remarkable ductility, durability, and mechanical properties. However, the manufacture of UHPC can cause serious environmental issues. This work addresses the feasibility of using aeolian sand to produce UHPC, and the mix design, environmental impact, and mechanical characterization of UHPC are investigated. We designed the mix proportions of the UHPC according to the modified Andreasen and Andersen particle packing model. We studied the workability, microstructure, porosity, mechanical performance, and environmental impact of UHPC with three different water/binder ratios. The following findings were noted: (1) the compressive strength, flexural strength, and Young’s modulus of the designed UHPC samples were in the ranges of 163.9–207.0 MPa, 18.0–32.2 MPa, and 49.3–58.9 GPa, respectively; (2) the compressive strength, flexural strength, and Young’s modulus of the UHPC increased with a decrease in water/binder ratio and an increase in the steel fibre content; (3) the compressive strength–Young’s modulus correlation of the UHPC could be described by an exponential formula; (4) the environmental impact of UHPC can be improved by decreasing its water/binder ratio. These findings suggest that it is possible to use aeolian sand to manufacture UHPC, and this study promotes the application of aeolian sand for this purpose.

Preparation of polymeric foams with bimodal cell size: An application of heterogeneous nucleation effect of nanofillers

2019 ◽  
Vol 147 ◽  
pp. 107-115 ◽  
Author(s):  
Yang Chen ◽  
Chenglong Weng ◽  
Zhen Wang ◽  
Tim Maertens ◽  
Ping Fan ◽  
...  
Keyword(s):  
Cell Size ◽  
Heterogeneous Nucleation ◽  
Polymeric Foams ◽  
Nucleation Effect

scholarly journals Effect of Aggregate Type and Specimen Configuration on Concrete Compressive Strength

Crystals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 625 ◽  
Author(s):  
Sherif Yehia ◽  
Akmal Abdelfatah ◽  
Doaa Mansour
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Modulus Of Elasticity ◽  
American Concrete Institute ◽  
Recycled Aggregates ◽  
Concrete Compressive Strength ◽  
Split Tensile Strength ◽  
Standard Size ◽  
Noticeable Effect ◽  
The Difference

In this paper, concrete mixes utilizing two sizes of natural aggregate and two sources of lightweight and recycled aggregates were used to investigate the effect of aggregate type and specimen size and shape on the compressive strength of concrete. In addition, samples from ready-mix concrete producers with different strengths were evaluated using standard size cylinders and cubes. Results were obtained on the 7th, 28th, and 90th day. In addition, flexural strength, split tension, and modulus of elasticity were evaluated on the 28th and 90th day. Statistical analyses were conducted to examine the significance of the difference between the compressive strength values for each two mixes using tests of hypotheses. Moreover, other mechanical properties as a function of compressive strength were discussed and compared to those predicated by the American Concrete Institute (ACI) specifications. Results indicate specimen shape has a noticeable effect on the compressive strength as the Cylinder/Cube ratio on the 90th day was ranging between 0.781 and 0.929. The concrete compressive strength and modulus of elasticity were significantly affected by the aggregate type. The flexural strength and split tensile strength were less affected by the aggregate type, which was also confirmed by the values predicted with the ACI equations.

Effect of BaSO4 on the compressive strength and reduction behavior of pellets

2020 ◽  
Vol 117 (2) ◽  
pp. 207
Author(s):  
Jiantao Ju ◽  
Chenmei Tang ◽  
Xiangdong Xing ◽  
Shan Ren ◽  
Guangheng Ji
Keyword(s):  
Compressive Strength ◽  
Theoretical Basis ◽  
Energy Dispersive Spectrometer ◽  
Reduction Process ◽  
Reduction Degree ◽  
Experimental Conditions ◽  
Reduction Behavior ◽  
Influence Mechanism ◽  
Scanning Electron ◽  
Peak Value

To provide theoretical basis for the production of pellets, the effect of BaSO4 in the range of 0 to 5.0% on properties of pellets was studied under experimental conditions. The influence mechanism of BaSO4 on the compressive strength of preheated pellets as well as roasted pellets and reduction behavior of roasted pellets was investigated by means of scanning electron microscopy-energy dispersive spectrometer (SEM-EDS). From the results, it can be observed that the compressive strength of preheated pellets varies slightly whereas roasted pellets has a great change when BaSO4 content increases from 0 to 5%. The compressive strength of roasted pellets initially increases then decreases, which reaches the peak value of 3411 N with BaSO4 content of 1.5%. The reduction degree enhances from 80.7 to 97.9% and FeO content reduces from 2.33 to 1.57% with increasing BaSO4 content from 0 to 5.0%. The degree of polycrystalline of hematite improves and the hole size increases obviously when BaSO4 content varies from 0 to 1.5%. The crystallization of hematite decreases and the holes whose distribution is uneven increases when BaSO4 content is more than 1.5%. In reduction process, the wustite reduces and metallic iron increases with increasing BaSO4 content from 0 to 5.0%.

Research on the Basic Mechanical Properties of Fly Ash Fiber Reinforced Concrete

2011 ◽  
Vol 261-263 ◽  
pp. 8-12
Author(s):  
Shu Shan Li ◽  
Ming Xiao Jia ◽  
Dan Ying Gao
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Compressive Modulus ◽  
Fiber Reinforced Concrete ◽  
Cement Ratio ◽  
Influence Mechanism ◽  
Fiber Concrete ◽  
Early Strength

The basic mechanical properties of fly ash fiber concrete were tested. The influences to the compressive strength, splitting tensile strength and compressive modulus of elasticity of fiber concrete by water-cement ratio, dosage of fly ash and other factors were analyzed. The influence mechanism of fly ash to concrete is discussed. The results indicate that with the increase of the dosage of fly ash, the early strength of double-doped concrete is reduced, while the later strength of concrete was obviously increased.

scholarly journals Variasi Abu Ampas Tebu dan Serat Bambu sebagai Bahan Campuran Pembuatan Beton Ramah Lingkungan

2020 ◽  
Vol 4 (2) ◽  
pp. 109-117
Author(s):  
Warsito Warsito ◽  
Anita Rahmawati
Keyword(s):  
Compressive Strength ◽  
Sugarcane Bagasse ◽  
Design Method ◽  
Low Cost ◽  
Waste Product ◽  
American Concrete Institute ◽  
Raw Material ◽  
Mix Design ◽  
Fine Aggregate ◽  
The Times

ABSTRAKBeton merupakan suatu material yang secara umum menjadi kebutuhan masyarakat terhadap fasilitas infrastruktur konstruksi yang semakin meningkat seiring dengan perkembangan zaman, oleh sebab itu pemilihan beton sebagai bahan baku utama konstruksi bangunan sangatlah penting. Beberapa hal yang perlu ditinjau dalam pembuatan beton adalah harganya relatif murah, mudah diperoleh, memiliki kuat tekan tinggi serta mempunyai sifat tahan terhadap faktor kondisi lingkungan. Abu Ampas Tebu (AAT) adalah sisa hasil pembakaran dari ampas tebu. Ampas tebu sendiri merupakan hasil limbah buangan yang berlimpah dari proses pembuatan gula. Tujuan penelitian ini dimaksudkan untuk mengetahui kuat tekan beton yang menggunakan serat bambu dan abu ampas tebu sebagai pengganti agregat halus dengan variasi tertentu yang mencapai 40%. Penelitian ini menggunakan metode kuantitatif eksperimen dan teknik analisa data menggunakan regresi. Variabel yang digunakan dalam penelitian ini adalah variabel bebas yang berupa variasi penggantian sebagian agregat halus menggunakan abu ampas tebu dan serat bambu. Hasil penelitian ini adalah beton dengan perbandingan komposisi campuran yang didapat sebelumnya dan hasil mix design beton normal maut sedang yaitu dengan besar kuat tekan fc’ 14,5 Mpa (K175) sampai dengan fc’17,15 Mpa (K210,6) yang kemudian ditambah dengan bahan AAT sebagai bahan penambah semen dan serat Bambu.Kata Kunci: Abu Ampas Tebu, Beton, Serat Bambu, Agregat ABSTRACTConcrete is a material that generally supports the community's need for construction of infrastructure facilities which is increasing along with the times. Selection of concrete as the main raw material for building construction is very important. There are benefits in making concrete such as low cost, ease to obtain, high compressive strength and resistancy to environmental conditions. Bagasse Ash (AAT) is the residue from the burning of sugarcane bagasse. Sugarcane bagasse itself is an abundant waste product from the sugar making processes. The purpose of this study was to determine the compressive strength of concrete using bamboo fibers and the AAT as a substitute for fine aggregate with certain variations reaching up to 40% with a concrete enhancer chemical aggregate. This research used the American Concrete Institute design method with a value of 0.40 and 0.45 on the concrete age of 28 days. Results found that the samples made were hard concrete with a comparison of the composition of the mixture obtained previously. Results of a normal deadly concrete mix design comprised with a large compressive strength fc '14.5 Mpa (K175) to fc '17, 15 Mpa (K210,6) which was then added to the AAT as aggregates in the cement and Bamboo fiber.Keywords: Bagasse Ash, Concrete, Bamboo, Aggregate

scholarly journals Comparison between the British and American Methods in Designing Concrete using Local Aggregate in the City of Mosul Preparation

2021 ◽  
Vol 11 (6) ◽  
Author(s):  
Mohammed Taher Abdul Rahman Al-Haidari
Keyword(s):  
Compressive Strength ◽  
American Concrete Institute ◽  
Research Center ◽  
Building Research ◽  
Mixing Ratios ◽  
Applied Study ◽  
Concrete Mixtures ◽  
Soft State ◽  
Hardened State ◽  
American Method

This research included an applied study for the design of concrete mixtures by following the method of the American Concrete Institute (ACl) and the method of the Building Research Center in England (British method) to restriction which of these two methods is more suitable for use and application in the design of concrete mixtures when using local aggregate (gravel and sand taken from the area Badush and Aski Mosul), where job mixes were made using the mixing ratios obtained from these two methods, and a comparative study was made for the properties concrete resulting in the soft state (workability )and the hardened state (compressive resistance), and the results proved the following: A- In general, when discussing the results according to mixing ratios and workability levels, the method of the Building Research Center in England (the British method) gave higher results than the results obtained by the American Concrete Institute method (the American method) when using the above local aggregate whereas results shown increase in (workability) and Compressive strength. This increase amounts to the percentages shown in the table below: Compressive strength (%) Slump test (%) workability 10.48 14.40 Precipitation = 10-8 cm 12.10 21.40 Precipitation = 18-15 cm Table (1-1) B- It is possible to make another comparison, when fixing the proportion of water/cement, it turns out that the method of the Building Research Center in England (the British method) gives higher workability than the method of the American Concrete Institute (the American method) and for the same proportion of cement/ water, the American method gives Higher compressive strength than the British method. C- The building research center method is a more practical and applicable method more than the American Concrete Institute method because it takes the type of cement, the type of aggregate and other properties of the aggregate (especially particle shape) into consideration

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