scholarly journals Effect of Remixing & Intermittent Curing Sequences on Strength of Pavement Quality Concrete

2020 ◽  
Vol 9 (4) ◽  
pp. 2000-2013
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Fresh Concrete ◽  
Time Lag ◽  
Blend Ratio ◽  
Curing Method

The paper is concerned with determining the effect of remixing of two different grades of concrete proving blend ratio, time lag & intermittent curing sequence. Two mix designs (M40 & M50) selected and provide blend ratio (0 to infinity) at 0,30,60,90 & 120min time lag. In this research, the problem related to improper casting & curing sequence, which ultimate formation of the cold joint due to old and fresh concrete. Curing method applied with four sequences Air0 Water28, Air28 Water0, Air7 Water21, and Air21 Water7.Concrete samples were made and tested for their compressive strength, flexural strength, elastic modulus, and shrinkage properties in the laboratory. As compared to the strength of freshly prepared concretes to the hard in situ concrete tends to show a reduction in its various strengths due to improper curing & formation of cold joints. This reduction is further possible to be minimized to a certain extent on blending some quantity of a relatively fresh mix to the existing quantity of the hard in situ concrete.

scholarly journals Prediction of Strength of Remixed Concrete by Application of Orthogonal Decomposition, Neural Analysis and Regression Analysis

2019 ◽  
Vol 9 (1) ◽  
pp. 434-443
Author(s):  
K.L. Bidkar ◽  
P.D. Jadhao
Keyword(s):  
Compressive Strength ◽  
Regression Analysis ◽  
Fresh Concrete ◽  
Time Lag ◽  
Lag Time ◽  
Orthogonal Decomposition ◽  
The Other ◽  
Blend Ratio ◽  
Analysis Tools

AbstractCompressive strength is the foremost property of concrete which is influenced by a number of parameters. These parameters plays important role for the characteristics achieved by concrete. Orthogonal decomposition, neural analysis and regression analysis tools can be utilized where the dependence and independence of these parameters to be considered. In this paper these analyses are considered for remix concrete, in which apart from the cement contents, w/c ratio, proportions of C.A., F.A., the other parameters like blend ratio (r=Qo/Qf, Qo=quantity of old partially set concrete, Qf =quantity of fresh concrete) time lag ( time between preparation and placing of concrete) also plays the important role.

scholarly journals Assessment of the Rheological and Mechanical Properties of Geopolymer Concrete Comprising Fly Ash and Fluid Catalytic Cracking Residue as Aluminosilicate Precursor

2021 ◽  
Vol 11 (7) ◽  
pp. 3032
Author(s):  
Tuan Anh Le ◽  
Sinh Hoang Le ◽  
Thuy Ninh Nguyen ◽  
Khoa Tan Nguyen
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Flexural Strength ◽  
Catalytic Cracking ◽  
Fluid Catalytic Cracking ◽  
High Alumina ◽  
Geopolymer Concrete ◽  
Sem Images

The use of fluid catalytic cracking (FCC) by-products as aluminosilicate precursors in geopolymer binders has attracted significant interest from researchers in recent years owing to their high alumina and silica contents. Introduced in this study is the use of geopolymer concrete comprising FCC residue combined with fly ash as the requisite source of aluminosilicate. Fly ash was replaced with various FCC residue contents ranging from 0–100% by mass of binder. Results from standard testing methods showed that geopolymer concrete rheological properties such as yield stress and plastic viscosity as well as mechanical properties including compressive strength, flexural strength, and elastic modulus were affected significantly by the FCC residue content. With alkali liquid to geopolymer solid ratios (AL:GS) of 0.4 and 0.5, a reduction in compressive and flexural strength was observed in the case of geopolymer concrete with increasing FCC residue content. On the contrary, geopolymer concrete with increasing FCC residue content exhibited improved strength with an AL:GS ratio of 0.65. Relationships enabling estimation of geopolymer elastic modulus based on compressive strength were investigated. Scanning electron microscope (SEM) images and X-ray diffraction (XRD) patterns revealed that the final product from the geopolymerization process consisting of FCC residue was similar to fly ash-based geopolymer concrete. These observations highlight the potential of FCC residue as an aluminosilicate source for geopolymer products.

scholarly journals Examining Polyethylene Terephthalate (PET) as Artificial Coarse Aggregates in Concrete

2020 ◽  
Vol 6 (12) ◽  
pp. 2416-2424
Author(s):  
Erniati Bachtiar ◽  
Mustaan Mustaan ◽  
Faris Jumawan ◽  
Meldawati Artayani ◽  
Tahang Tahang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Polyethylene Terephthalate ◽  
Coarse Aggregate ◽  
Fresh Concrete ◽  
Coarse Aggregates ◽  
Volume Weight ◽  
Concrete Mixtures ◽  
Strength Tests ◽  
Recycled Polyethylene

This study aims to examine the effect of recycled Polyethylene Terephthalate (PET) artificial aggregate as a substitute for coarse aggregate on the compressive strength and flexural strength, and the volume weight of the concrete. PET plastic waste is recycled by heating to a boiling point of approximately 300°C. There are five variations of concrete mixtures, defined the percentage of PET artificial aggregate to the total coarse aggregate, by 0, 25, 50, 75 and 100%. Tests carried out on fresh concrete mixtures are slump, bleeding, and segregation tests. Compressive and flexural strength tests proceeded based on ASTM 39/C39M-99 and ASTM C293-79 standards at the age of 28 days. The results showed that the use of PET artificial aggregate could improve the workability of the concrete mixture. The effect of PET artificial aggregate as a substitute for coarse aggregate on the compressive and flexural strength of concrete is considered very significant. The higher the percentage of PET plastic artificial aggregate, the lower the compressive and flexural strength, and the volume weight, of the concrete. Substitution of 25, 50, 75 and 100% of PET artificial aggregate gave decreases in compressive strength of 30.06, 32.39, 41.73 and 44.06% of the compressive strength of the standard concrete (18.20 MPa), respectively. The reductions in flexural strength were by respectively 19.03, 54.50, 53.95 and 61.00% of the standard concrete's flexural strength (3.59 MPa). The reductions in volume weight of concrete were by respectively 8.45, 17.71, 25.07 and 34.60% of the weight of the standard concrete volume of 2335.4 kg/m3 Doi: 10.28991/cej-2020-03091626 Full Text: PDF

scholarly journals Kajian Karakteristik Beton Memadat Sendiri yang Menggunakan Serat Ijuk (Hal. 54-65)

2018 ◽  
Vol 4 (4) ◽  
pp. 54
Author(s):  
Iis Nurjamilah ◽  
Abinhot Sihotang
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Coarse Aggregate ◽  
Fresh Concrete ◽  
High Strength ◽  
Self Compacting Concrete ◽  
Palm Fiber ◽  
Fiber Concrete ◽  
Dilute Mixture

ABSTRAKKajian karakteristik beton memadat sendiri yang menggunakan serat ijuk merupakan sebuah kajian yang dilakukan untuk mengetahui pengaruh penambahan serat ijuk terhadap karakteristik beton memadat sendiri (SCC). Beton memadat sendiri yang menggunakan serat ijuk (PFSCC) didesain memiliki campuran yang encer, bermutu tinggi (= 40 MPa) dan memiliki persentase kekuatan lentur yang lebih baik. PFSCC  didapatkan dari hasil pencampuran antara semen sebanyak 85%, fly ash 15%, superplastizicer 1,5%, serat ijuk 0%, 0,5%; 1%; 1,5%; 2% dan 3% dari berat binder (semen + fly ash), kadar air 190 kg/m3, agregat kasar 552,47 kg/m3 dan pasir 1.063 kg/m3. Semakin banyak persentase penambahan serat ijuk ke dalam campuran berdampak terhadap menurunnya workability beton segar. Penambahan serat ijuk yang paling baik adalah sebanyak 1%, penambahan tersebut dapat meningkatkan kekuatan tekan beton sebesar 13% dan lentur sebesar 1,8%.Kata kunci: beton memadat sendiri (SCC), beton berserat, beton memadat sendiri yang menggunakan serat ijuk (PFSCC), serat ijuk ABSTRACTThe study of characteristics self compacting concrete using palm fibers is a study conducted to determine the effect of adding palm fibers to characteristics of self compacting concrete (SCC). palm fibers self compacting concrete (PFSCC) is designed to have a dilute mixture, high strength (= 40 MPa), and have better precentage flexural strength. PFSCC was obtained from mixing of 85% cement, 15% fly ash, 1.5% superplastizicer, 0%, 0.5%, 1%, 1.5%, 2% and 3% palm fibers from the weight of binder  (cement + fly ash), water content 190 kg/m3, coarse aggregate 552.47 kg/m3 and sand 1,063 kg/m3. The more persentage palm fibers content added to the mixture makes workability of fresh concrete decreases. The best addition of palm fiber is 1%, this addition can increases the compressive strength 13% and flexural strength 1.8%.Keywords: self compacting concrete (SCC), fiber concrete, Palm fiber self compacting concrete (PFSCC), palm fiber

Evaluation of Relations among Basic Mechanical Properties of Concrete with Machine-Made Sand

2011 ◽  
Vol 418-420 ◽  
pp. 441-444 ◽  
Author(s):  
Feng Lan Li ◽  
Yan Zeng ◽  
Chang Yong Li
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Rough Surface ◽  
Design Code ◽  
Ordinary Concrete ◽  
Axial Compressive Strength ◽  
Different Characteristics

Due to many different characteristics such as irregular polygon particle with pointed edges, rough surface and larger content of stone powder, machine-made sand has ignorable effects on the properties of concrete. As the basis for the design of concrete structures, the relations among the basic mechanical properties of concrete such as compressive strength, tensile strength, flexural strength and elastic modulus should be clearly understood. This paper summarizes the test data from the published references, and discusses the relations among these properties by statistical analyses compared with those of ordinary concrete. The results show that the axial compressive strength and the tensile strength can be prospected by the same formulas of ordinary concrete specified in current Chinese design code, but the prospected tensile strength should multiply a reducing coefficient when the strength grade of concrete is lower than C30. The elastic modulus of concrete with machine-made sand is larger than that of ordinary concrete, which should be prospect by the formula in this paper. Meanwhile, the formula of flexural strength is suggested.

Influence of Variable Temperature Curing on Mechanical Properties of Fly Ash Concrete

2011 ◽  
Vol 250-253 ◽  
pp. 178-181
Author(s):  
Ya Ding Zhao ◽  
Xue Ying Li ◽  
Ling Chao Kong ◽  
Wei Du
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Flexural Strength ◽  
Variable Temperature ◽  
Improve Performance ◽  
Curing Conditions ◽  
Fly Ash Concrete ◽  
Better Than

Under variable temperature curing conditions(30 oC ~70 oC), concrete with fly ash whose compressive strength, flexural strength, and dynamic elastic modulus are better than ones without fly ash.Compared with constant temperature 20oC, 50 oC and 70 oC, variable temperature curing(VTC) is benefit for the improvement of mechanical properties of 30% fly ash concrete, but which is no advantage to improve performance of 50% fly ash concrete.

scholarly journals Mechanical Properties of Coarse Aggregate Electric Arc Furnace Slag in Cement Concrete

2021 ◽  
Vol 7 (10) ◽  
pp. 1716-1730
Author(s):  
Huu-Bang Tran
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Flexural Strength ◽  
Silica Fume ◽  
Arc Furnace ◽  
Coarse Aggregates ◽  
Eaf Slag ◽  
Electric Arc Furnace Slag ◽  
Furnace Slag

The feasibility of using EAF slag aggregate, fly ash, and silica fume in pavement Electric Arc Furnace Slag Concrete (CEAFS) is the focus of this research. EAF slag aggregate is volume stable and suitable for use in concrete, according to the findings of the testing. EAF slag was utilized to replace natural coarse aggregates in the CEAFS mixes. CEAFS was created by blending 50% crushed stone with 50% EAF slag in coarse aggregates, with fly ash (FA) and silica fume (SF) partially replacing cement at content levels (i.e. FA: 0, 20, 30, and 40%; SF: 0, 5, and 10%). The soil compaction approach was used to evaluate the optimal moisture level for CEAFS mixes containing EAF slag aggregate fly ash and silica fume. A testing program was used to investigate the weight of CEAFS units and their mechanical qualities (compressive strength, flexural strength, and elastic modulus). As a result, the fresh and hardened unit weights in the CEAFS are comparable. Moreover, variations in the concentration of mineral additives FA and SF in adhesives, as well as the CEAFS mixed aggregate ratio, have an impact on compressive strength, flexural strength, and elastic modulus at all ages. However, combining EAF slag aggregate with (FA0% +SF10%; FA10% +SF0%; FA10% +SF10%; and FA20% +SF10%) the CEAFS mixtures have improved mechanical characteristics over time. According to this study, CEAFS pavements can be made with EAF slag aggregate fly ash and silica fume. In addition, a formula correlation was suggested to compute CEAFS (i.e. compressive strength with elastic modulus and compressive strength with flexural strength). Doi: 10.28991/cej-2021-03091755 Full Text: PDF

Effect of Low Temperature on Mechanical Properties of Concrete with Different Strength Grade

2011 ◽  
Vol 477 ◽  
pp. 308-312 ◽  
Author(s):  
Xiao Ping Cai ◽  
Wen Cui Yang ◽  
Jie Yuan ◽  
Yong Ge ◽  
Bao Sheng Zhang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Low Temperature ◽  
Flexural Strength ◽  
Splitting Tensile Strength ◽  
Growth Ratio ◽  
Strength Grade

The effect of low temperature (-35°C) on the mechanical properties of concrete with different strength grade such as compressive strength, flexural strength, splitting tensile strength and elastic modulus was studied. The results showed that all of the mechanical properties were improved at -35°C. It was also can be found from the tests, as the strength grade increased, the growth ratios at -35°C of compressive strength, flexural strength and splitting tensile strength decreased. But the growth ratio of elastic modulus increased with the increasing of strength grade.

Effect of the Ratio of Silica Source on Ultra-Light Calcium Silicate Material In Situ Strengthened with Xonotlite Whiskers

2013 ◽  
Vol 648 ◽  
pp. 131-134 ◽  
Author(s):  
Fei Liu ◽  
Ting Li ◽  
Xiao Dan Wang ◽  
Jian Xin Cao
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Hydrothermal Synthesis ◽  
Flexural Strength ◽  
Calcium Silicate ◽  
In Situ Growth ◽  
Silicate Material ◽  
Silica Source ◽  
Microstructure And Mechanical Properties

The ultra-light calcium silicate material was reinforced with the method of xonotlite whisker in-situ growth via hydrothermal synthesis. Effects of different ratios of silica sources on microstructure and mechanical properties of the reinforcement were studied in this paper. The results indicated that the ratios of silica sources posed great impacts on microstructure and mechanical properties of the reinforcement. The reinforcement with density of 118 Kg•m-3, flexural strength of 0.42 MPa and compressive strength of 0.66 MPa was successfully prepared under the condition of K2SiO3:H2SiO3 (mol) =2:1.

Effect on Mechanical Properties of Rubberized Concrete due to Pretreatment of Waste Tire Rubber with NaOH

2013 ◽  
Vol 357-360 ◽  
pp. 897-904 ◽  
Author(s):  
Qing Wen Ma ◽  
Jin Chao Yue
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Strain Ratio ◽  
Zinc Stearate ◽  
Ultimate Strain ◽  
Rubberized Concrete ◽  
Volume Percentage ◽  
Strength Tests ◽  
Rubber Particles

Rubber particles were dipped into NaOH solution in order to wipe the zinc stearate generated in the process of preparation of rubber power. Rubber with different particle diameters and mixing amount (sand replaced in equal volume percentage) was adopted to produce rubberized concrete specimens. A series of tests including compressive strength tests, flexural strength tests, elastic modulus tests and ultimate strain ratio tests were done respectively. The results of tests showed that the value of the compressive strength, flexural strength and elastic modulus decreased with the increase of the mixing amount of rubber, while the decrease amplitude was different from each other. The value of ultimate strain increased a little and the ability of toughness and deformation of rubberized concrete were enhanced obviously through dipping rubber particles into NaOH solution.

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