scholarly journals Influence of Humidity on the Elastic Modulus and Axis Compressive Strength of Concrete in a Water Environment

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5696
Author(s):  
Guohui Zhang ◽  
Changbing Li ◽  
Hai Wei ◽  
Mingming Wang ◽  
Zhendong Yang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Water Saturation ◽  
Water Environment ◽  
Systematic Research ◽  
Saturation State ◽  
Soaking Time ◽  
Axial Compressive Strength ◽  
Saturated Concrete ◽  
Compressive Strength Of Concrete

Concrete structures are often in different humidity conditions that have a significant impact on the elastic modulus of concrete, therefore, systematic research on the evolution of the law of concrete elastic modulus under different humidity conditions is needed. In this study, the variation laws of the water saturation of concrete specimens with strength grades C15, C20, and C30 were obtained, and then the influence laws of the water saturation on the concrete axial compressive strength were carried out, and the prediction model of elastic modulus of concrete with respect to water saturation was constructed. The results showed that the water saturation of concrete with strength grades C15, C20, and C30 increased with an extension of immersion time, and the water saturation showed an approximately linear rapid growth within three soaking hours, reaching 47.56%, 71.63%, and 47.29%, respectively. Note, the concrete reached saturation state when the soaking time was 240 h. The axial compressive strength with strength grades C15, C20, and C30 decreased with increased water saturation, and the axial compressive strength of saturated concrete decreased by 27.25%, 21.14%, and 20.76%, respectively, as compared with the dry state concrete. The elastic modulus of concrete with strength grades C15, C20, and C30 increased with increased water saturation, and the elastic modulus of saturated concrete was 1.18, 1.19, and 1.24 times higher than those of dry concrete, respectively.

scholarly journals Bond Properties of Steel Bar in Concrete under Water Environment

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3517 ◽  
Author(s):  
Li Song ◽  
Fulai Qu ◽  
Guirong Liu ◽  
Shunbo Zhao
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Water Environment ◽  
Splitting Tensile Strength ◽  
Soaking Time ◽  
Bond Slip ◽  
Pull Out ◽  
Steel Bar ◽  
Compressive Strength Of Concrete ◽  
Good Agreement

The present study concerns the bond behavior of steel bar in concrete under a water environment. This topic was put forward because of the changes of concrete under a water environment and the importance of reliable anchorage of steel bar for reinforced concrete structures. Thirty bond specimens with deformed steel bars were immersed in water and experimentally studied by pull-out tests. The soaking time from 28 day to 360 day and the cubic compressive strength of concrete with 20 N/mm2 and 40 N/mm2 were considered as the main parameters. The results indicate that the moisture content, compressive strength, and splitting tensile strength of concrete are affected by the water environment; the splitting tensile strength varies almost linearly with the compressive strength of concrete; and the descent portion of the bond–slip curve dropped slowly owing to the confinement of stirrups. On the basis of the test data, the formulas for the prediction of bond strength, residual strength, and the corresponding slips with different soaking time are proposed. Finally, the constitutive relation of bond–slip with two portions in the water environment is established with good agreement with the experimental bond–slip curves.

Fuzzy application in the prediction of axial compressive strength of Portland concrete based on traces and curing time

2021 ◽  
Author(s):  
DENNIS SANTOS TAVARES ◽  
BRUNA CAMPOS AMARAL ◽  
DAVID AUGUSTO RIBEIRO ◽  
TADAYUKI YANAGI JUNIOR ◽  
FRANCISCO CARLOS GOMES ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Construction Industry ◽  
Fuzzy Systems ◽  
Main Property ◽  
Membership Functions ◽  
Curing Time ◽  
Axial Compressive Strength ◽  
Compressive Strength Of Concrete ◽  
Input Variables ◽  
Main Material

Concrete is the main material used in the construction industry and its main property is the axial compressive strength. Usually the prediction of compressive strength is restricted to limited empirical equations and / or laboratory dosages. The objective of this study is to develop fuzzy systems capable of obtaining the axial compressive strength of concrete, from the mixtures and curing time. Several fuzzy systems were developed with Mamdani inference and different defuzzification methods. Triangular membership functions were adopted for the input variables in all systems and triangular functions for the output variables. The developed models were simulated and evaluated using three statistical indexes. The systems with Mamdani inference and centroid, bisector and mom defuzzification proved to be reliable and highly effective. The best performance was obtained by the fuzzy centroid defuzzification system according to the analyses.,

Effects of Concrete Compositions on the Elastic Modulus

2021 ◽  
Vol 322 ◽  
pp. 41-47
Author(s):  
Rudolf Hela ◽  
Lenka Bodnárová ◽  
Klára Křížová
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Negative Impact ◽  
The Other ◽  
Technological Factors ◽  
Factors Influencing ◽  
Other Hand ◽  
Eurocode 2 ◽  
Compressive Strength Of Concrete ◽  
Reducing Costs

The paper comments on the influence of various technological factors influencing the values of elastic modulus. Today, the composition of concrete combines the classic input components with the significant use of mixed cements, active admixtures and superplasticizers in order to achieve the required compressive strength of concrete and durability while reducing costs. On the other hand, the composition of these concretes has a negative impact on the elastic modulus which are significantly lower than the values derived from compressive strength in Eurocode 2. At the end of the article is a list of measures that are a prerequisite for obtaining the required concrete elastic modulus.

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.

Experimental Study on the Axial Compressive Strength and Elastic Modulus of GHPFRCC

2013 ◽  
Vol 357-360 ◽  
pp. 1138-1141 ◽  
Author(s):  
Xiu Ling Li ◽  
Wang Juan
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
High Performance ◽  
Construction Material ◽  
Structure Design ◽  
Sustainable Construction ◽  
High Performance Fiber ◽  
Maintenance Decisions ◽  
Axial Compressive Strength ◽  
Pva Fiber

The sustainability of the construction material is increasingly coming to the forefront of the structure design and maintenance decisions. To address this, development of a new class of more sustainable construction material is needed, especially in China. This paper reports on the development of the green high-performance fiber-reinforced cementitious composites (GHPFRCC) with high volumes of fly ash and PVA fiber, and emphasizes the axial compressive strength and elastic modulus of GHPFRCC. Experimental results show that the prism axial compressive strength of GHPFRCC ranges from 15MPa to 40MPa. The elastic modulus of GHPFRCC is around 16-35GPa, typically lower than concrete.

scholarly journals Research on the influence of boulder powder content on concrete performance

2021 ◽  
Vol 293 ◽  
pp. 02009
Author(s):  
Guangcheng Meng
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Mineral Admixtures ◽  
Cement Concrete ◽  
Satisfactory Performance ◽  
Compressive Strength Of Concrete ◽  
Electric Flux ◽  
Granite Powder ◽  
Powder Content

To solve the problem of environmental pollution caused by the accumulation of granite powder and the shortage of traditional mineral admixtures, the influence of the amount of granite powder on the mechanical properties of concrete was studied by replacing cement with different amount of granite powder Different amount of granite powder can be used to prepare concrete with satisfactory performance. When the amount of granite powder is small (not more than 5%), granite powder will not reduce the compressive strength of concrete, or even slightly improve the compressive strength of pure cement concrete. When the amount of granite powder is more than 5%, the compressive strength of concrete will gradually decrease; when the amount of granite powder is more than 5%, the compressive strength of concrete will gradually decrease. The elastic modulus of concrete decreased, and the electric flux increased with the increase of the amount of admixture.

Basic Mechanics Characters of Recycled Fine Aggregate Concrete

2012 ◽  
Vol 446-449 ◽  
pp. 2028-2032 ◽  
Author(s):  
Jian Geng ◽  
Yong Yong Chen ◽  
Jia Ying Sun ◽  
Wei Chen
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Fine Aggregate ◽  
Aggregate Concrete ◽  
Recycled Fine Aggregate ◽  
Minimum Particle Size ◽  
Axial Compressive Strength ◽  
Mechanical Characters

In this article, the basic mechanical characters of recycled fine aggregate concrete (RFAC) are studied, and the relationships of recycled fine aggregate (RFA) content, minimum particle size and water content with them are also discussed according to results of cubic compressive strength （f¬¬cu）, flexural strength （ff）, splitting tensile strength（fts）, axial compressive strength（fc）and Yang’s modulus （Ec）. The results indicate that the use of RFA will induce mechanical properties of RFAC to deteriorate, and the deteriorated trend of it become more obviously with RFA content increased and minimum particle size reduced, in addition to, the early compressive strength of RFA develop slowly. The RFAC elastic modulus is significantly lower than ordinary concrete, besides, RFA on elastic modulus was significantly affected than other mechanical properties.

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

2013 ◽  
Vol 438-439 ◽  
pp. 15-19
Author(s):  
Chun Jie Liu ◽  
Chun Yan Jia ◽  
Chang Yong Li
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Concrete Structures ◽  
Ordinary Concrete ◽  
Strength Grade ◽  
Fly Ash Concrete ◽  
Axial Compressive Strength

Although the machine-made sand was widely used for concrete in recent years in China, it was short of studies on the relations among the basic mechanical properties of fly-ash concrete with machine-made sand (MSFAC). However, these relations such as the compressive strength, the tensile strength and the elastic modulus with the cubic compressive strength (i.e. strength grade) are the basis of design for concrete structures. 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 only the tensile strength of MSFAC can be safely forecasted by the same formula of ordinary concrete specified in current Chinese design code. When the strength grade is higher than C45, the axial compressive strength of MSFAC is largely forecasted by the formula of ordinary concrete. The elastic modulus of MSFAC is larger than that of ordinary concrete, which should be prospect by the formula in this paper. This work gives out some cautions for the proper use of the MSFAC in concrete structures.

Experimental Study of Composite High Strength Self-Compacting Concrete

2017 ◽  
Vol 865 ◽  
pp. 289-294
Author(s):  
Xi Ri Kang ◽  
Guang Xiu Fang
Keyword(s):  
Compressive Strength ◽  
Engineering Application ◽  
High Strength ◽  
Cementitious Material ◽  
Self Compacting Concrete ◽  
Design Strength ◽  
Mix Proportion ◽  
Optimal Mix ◽  
Axial Compressive Strength ◽  
Compressive Strength Of Concrete

This test uses polycarboxylate superplasticizer by adding 15% quantitative fly ash, 10%, 15%, 20% of slag, and 5%,7.5%, 10% of silica fume of the total amount of the cementitious material to be an equivalent replacement for cement. Ordinary materials were used to make the C70 high strength self-compacting concrete. The concrete slump, expansion degree, and the axial compressive strength of concrete were studied. Through testing, the mix proportion of each group of concrete slump was determined to be above 250mm. And the expansion degree to be above 550mm. The axial compressive strength satisfied the design strength value. At the same time, the optimal mix ratio was proposed. And the economic performance of each group was analyzed. There are references for a similar experimental design and engineering application.

scholarly journals Experimental investigation on the use of steel-concrete bond tests for estimating axial compressive strength of concrete: part 1

2013 ◽  
Vol 6 (5) ◽  
pp. 715-736 ◽  
Author(s):  
B. V. Silva ◽  
M. P. Barbosa ◽  
L. C. P. Silva Filho ◽  
M. S. Lorrain
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Low Cost ◽  
Low Complexity ◽  
Bond Stress ◽  
Pull Out ◽  
Technological Control ◽  
Axial Compressive Strength ◽  
Compressive Strength Of Concrete ◽  
Bond Tests

This study analyzes the feasibility of using steel-concrete bond tests for determining the compressive strength of concrete in order to use it as a complement in the quality control of reinforced concrete. Lorrain and Barbosa (2008) 14] and Lorrain et al. (2011) 15] justify the use of a modified bond test, termed APULOT, to estimate the compressive strength of concrete, hence increasing the possibilities for the technological control of reinforced concrete for constructions. They propose an adaptation of the traditional pull-out test (POT) method, standardized by the CEB / FIP RC6: 1983 8], because it is a low complexity and low cost test. To enable the use of the APULOT test as a technological control test of concrete at construction sites requires determining its methodology and adapting the experimental laboratory practice to the construction itself. The aim of this study is to evaluate the possibility of conducting compressive strength estimates using bond stress data obtained by the traditional pull-out tests (POT). Thus, two concrete compositions of different classes were tested at 3, 7 and 28 days. Ribbed bar specimens (nominal diameters of 8, 10 and 12.5 mm) were also used in the preparation stage, totaling 108 POT tests. The results show that the correlation between the maximum bond stress and the compressive strength of concrete is satisfactory in predetermined cases, at all ages tested, reinforcing the purpose of consolidating this test as a complementary alternative to control the quality of reinforced concrete. In the second part of this paper the test results obtained with the APULOT method are presented and discussed.

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