scholarly journals Mechanical Behavior of Recycled Fine Aggregate Concrete with High Slump Property in Normal- and High-Strength

Author(s):  
Minkwan Ju ◽  
Kyoungsoo Park ◽  
Won-Jun Park

AbstractThis study investigated the mechanical behavior of normal strength (NS) and high strength (HS) concrete containing recycled fine aggregates (RFAs). A high slump mixing design was employed, which may be potentially used as filled structural concrete. The compressive strength, tensile strength, and elastic modulus were measured according to the RFA replacement ratio and curing time. In addition, the shrinkage strain was measured in a temperature and humidity chamber over 260 days. The compressive strength and elastic modulus of RFA concrete were approximately 70–90% of those of virgin concrete. The decreases in the compressive strength and elastic modulus for NS concrete were larger than those for HS concrete. This could be explained by the difference in failure mechanism between NS and HS concrete. The average ratio of the compressive strength at 190 days to that at 28 days was 1.15–1.3, and the ratio of the tensile strength at 190 days to that at 28 days was 1.15–1.25. These demonstrate good strength development. The ratios between the elastic modulus and compressive strength for RFA concrete were dissimilar to those for virgin concrete but similar to those for recycled coarse aggregate concrete. ACI 318-14 (Building code requirements for structural concrete and commentary, 2014) and Model Code (Fib model code for concrete structures, 2010) overestimated the elastic modulus of RFA concrete. Therefore, this study suggested an empirical expression to approximate the elastic modulus of RFA concrete. The increase in shrinkage owing to the use of RFA was at most 5–6% of the ultimate compressive strain of concrete.

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yanlin Huang ◽  
An Zhou

In recent years, with the rapid development of the construction industry, the demand for natural river sand has become increasingly prominent. Development of alternatives to river sand has become an interesting direction for concrete research. In this paper, coal gangue was proposed to replace part of the river sand to produce coal gangue fine aggregate concrete, while waste polyethene terephthalate (PET) bottles were used as raw materials to make PET fibers to improve the mechanical properties of coal gangue fine aggregate concrete. There were two parts of the test conducted. In the first part, the compressive strength of the gangue fine aggregate concrete cube, splitting tensile strength, axial compressive strength, and static elastic modulus were studied when the substitution rate of coal gangue increased from 0% to 50%. Referring to the equation of the full stress-strain curve of plain concrete, the stress-strain constitutive equation of coal gangue fine aggregate concrete was analyzed and studied. By comparing with plain concrete, it was found that the coal gangue concrete with a replacement rate of 50% had higher compressive strength and tensile strength, but its brittleness was significantly greater than that of plain concrete in the later stage. In the second part, by studying the effect of different PET fiber content on the mechanical properties of coal gangue fine aggregate concrete with a replacement rate of 50%, it was found that when the addition of PET fiber was 0.1% and 0.3%, not only were compressive strength, splitting tensile strength, static elastic modulus, and flexural strength of the gangue fine aggregate concrete effectively improved but also the brittleness of concrete can be significantly reduced. The study found that after adding 0.3% PET fiber, the coal gangue fine aggregate concrete with a replacement rate of 50% has better mechanical properties and less brittleness.


2012 ◽  
Vol 446-449 ◽  
pp. 2028-2032 ◽  
Author(s):  
Jian Geng ◽  
Yong Yong Chen ◽  
Jia Ying Sun ◽  
Wei Chen

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.


2021 ◽  
Vol 31 (1) ◽  
pp. 139-160
Author(s):  
Mehdi Khoshvatan ◽  
Majid Pouraminia

Abstract In the paper, the effects of different percentages of additives (perlite, LECA, pumice) on the mechanical properties of structural lightweight aggregate concrete were tested and evaluated. For the research, 14 mixing designs with different amounts of aggregate, water, and cement were made. Experimental results showed that the specific gravity of lightweight structural concrete made from a mixture of LECA, pumice, and perlite aggregates could be 25-30% lighter than conventional concrete. Lightweight structural concrete with a standard specific gravity can be achieved by using a combination of light LECA with perlite lightweight aggregates (LA) and pumice with perlite in concrete. The results indicated that LECA lightweight aggregates show more effective behavior in the concrete sample. Also, the amount of cement had a direct effect on increasing the strength regardless of the composition of LAs. The amount of cement causes compressive strength to increase. Furthermore, the stability of different experimental models increased from 156 to 345 kg m 3 while increasing the amount of cement from 300 to 400 kg m 3 in the mixing designs of LECA and perlite for W/C ratios of 0.3, 0.35, and 0.4. For a fixed amount of cement equal to 300 kg, the compressive strength is reduced by 4% by changing the water to cement ratio from 0.5 to 0.4. The compression ratios of strength for 7 to 28 days obtained in this study for lightweight concrete were between 0.67-0.8. Based on the rate of tensile strength to compressive strength of ordinary concretes, which is approximately 10, this ratio is about 13.5 to-17.8 in selected and optimal lightweight concretes in this research, which can be considered good indirect tensile strength for structural lightweight concretes.


2019 ◽  
Vol 14 (1) ◽  
pp. 30
Author(s):  
Handika Setya Wijaya ◽  
Adrianus Tandi

Concrete is one of the construction materials that is currently widely used by the community to build buildings. This is evidenced by the large number of construction of buildings, roads, irrigation channels and other construction. Until now, Indonesian people still use a little concrete. The problem that we want to know is how the effect of adding mosquito wire fiber to compressive strength, tensile strength and elastic modulus of concrete using concrete quality fc '= 19.3 MPa. The purpose of this study is to add additional mosquito wire fiber can be used as an added component of concrete components that have high strength and good quality but are economically valuable for compressive strength, tensile strength and elastic modulus. The method used is secondary and primary data. The results of this study are compressive strength 0% = 15,839 MPa, 1% = 13,657 MPa, 3% = 10,137 MPa, 5% = 9,173 MPa, tensile strength 0% = 7,392 MPa, 1% = 8,205 MPa, 3% = 8,504 MPa, 5% = 9,038 MPa. and elastic modulus 0% = 29131,385 N / mm2, 1% = 14575.68 N / mm2, 3% = 10303,133 N / mm2, 5% = 7030,893 N / mm2. The results of this study found that the addition of mosquito wire fiber can reduce the compressive strength of concrete and modulus. While the tensile strength and modulus of elasticity increase. So that the mosquito wire is not suitable for concrete compressive strength and elastic modulus.


2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Kyoung-Chul Kim ◽  
In-Hwan Yang ◽  
Changbin Joh

This paper describes an experimental study on the mechanical properties of high-strength fiber-reinforced concrete (HSFRC). The experimental parameters included the content and length of the steel fiber as well as the use of either a single-type fiber or hybrid steel fibers. The steel fiber contents were 1.0, 1.5, and 2.0% based on the volume of HSFRC, and the steel fiber lengths were 13, 16.5, and 19.5 mm. In addition, hybrid steel fibers incorporating steel fibers of different lengths were used. Compression tests and crack mouth opening displacement tests were performed for each HSFRC mixture with different experimental parameters. The mechanical properties of the HSFRC, such as compressive strength, elastic modulus, and tensile strength, increased with the steel fiber content. The mechanical property results of the HSFRC mixture using a single fiber length of 13 mm were greater than the results of the other mixtures. The compressive strength, elastic modulus, and tensile strength of the HSFRC mixture with hybrid steel fibers were similar to those of the mixtures with a single length of steel fiber. Additionally, based on the test results of the material properties, equations for predicting the elastic modulus and tensile strength of the HSFRC were suggested; the predictions using the proposed formula closely agreed with the experimental results.


2016 ◽  
Vol 722 ◽  
pp. 201-206 ◽  
Author(s):  
Tereza Pavlů ◽  
Magdaléna Šefflová

The main aim of this contribution is verification of durability properties of concrete with partial replacement of cement by recycled cement powder (RCP) sourced from pure waste concrete. The main topic of this article is the study of influence of partial replacement of cement by RCP to the carbonation resistance of fine aggregate concrete with partial replacement of cement. The compressive strength, tensile strength in bending and depth of carbonation were tested after 56 days of CO2 curing. Partial replacement of cement was 0, 5, 10 and 15 % for all these tests. The properties were investigated by using prismatic specimens.


2021 ◽  
Vol 55 (4) ◽  
Author(s):  
Dhanalakshmi A ◽  
M. Shahul Hameed

High-strength self-compacting concrete (HSSCC) is widely used as an eco-effective structure that is more durable than traditional cement that is more prone to demolitions and damage. One of today’s notable innovations is self-compacting concrete (SCC). The variety of materials and the utilization of siphons encourage the concrete’s use, which is significant. The worries about complex pieces are understandable due to the ease, with which precarious projecting zones are formed. This article presents high-strength self-compacting concrete, including quartz sand (QS) and marble-sludge powder (MSP) used as a partial replacement of fine aggregate (M sand). The substitution impact of QS and MSP on the strength of HSSCC is investigated. Further, V-funnel, L-box, slump flow, J-ring and slump cone are used to investigate the chemical, physical and mechanical properties such as splitting tensile strength, compressive strength, bond strength and flexural strength. The replacement of fine aggregate with 15 % of marble-sludge powder and 45 % of quartz sand (HSSCC concrete) gives an unprecedented outcome in the form of solidity and consistency. The findings show that the HSSCC 9 mix exhibits the compressive strength, splitting tensile strength, flexural strength and, more noteworthy, bond strength of 82.25 MPa, 8.10 MPa, 27.10 MPa and 11.89 MPa, respectively.


Author(s):  
I W. Intara ◽  
I M. Alit K. Salain ◽  
N. M. Anom Wiryasa

Research on the use of stone dust (SDT) as a partial replacement of Ordinary Portland Cement (OPC) has been carried out by using cylindrical concrete specimens with Ø = 150 mm and h = 300 mm. Specimens were made by using the ratio, in weight, of cementitious material : sand : crushed stone of 1.00 : 1.93 : 2.67. The water cementitious material ratio is of 0.52. The cementitious material is a mixture of OPC and SDT. The percentage of OPC replacement by SDT varied from 0%-25%. The distribution of grains of sand and crushed stone are designed according to SNI 03-2384-2000: gradation zone 2 for fine aggregate and gradation with a maximum diameter of 20 mm for coarse aggregate. The tests of compressive strength, elastic modulus, tensile strength and permeability on the cylindrical specimens were realized at 28 and 56 days. The result indicates that SDT shows a good pozzolanic reactivity in terms of compressive strength, elastic modulus, tensile strength and permeability. Therefore, it can be used as a component of Portland Cement Composite. The development of compressive strength, elastic modulus, tensile strength and permeability of concrete produced with a mixture of OPC and SDT depends on the amount of SDT used in the mixture and hydration time. The pozzolanic effect of SDT can only be seen at the age of 56 days. The optimal use of SDT as a partial replacement of OPC in concrete applications varied from 5%-10%.


2014 ◽  
Vol 629-630 ◽  
pp. 321-329
Author(s):  
Gai Fei Peng ◽  
Shuo Wang ◽  
Ting Li

This paper presents an original research on the influence of defects in recycled aggregate (RA) on mechanical properties of recycled aggregate concrete (RAC), including compressive strength, splitting tensile strength, fracture energy and elastic modulus. Six types of concretes, with the water to binder ratios (W/B) of 0.26 and 0.60, were prepared using nature aggregate (NA), RA and recycled aggregate treated by 3 mol/L (RA-H). Mechanical properties of RAC was inferior to that of NAC, and treated RA by sulfuric acid solution could improve the mechanical properties. Attached mortar in RA was the main factor resulting in the decrease of mechanical properties of RAC with 0.26 W/B, and for the RAC with 0.60 W/B, the effect of aggregate damage was more significant than that of attached mortar.


2017 ◽  
Vol 8 (4) ◽  
pp. 96
Author(s):  
Yousry B. I. Shaheen ◽  
Fatma M. Eid ◽  
Eng Eman Mahmoud

Sulfates in fine aggregate are a major problem when it exists in excessive amount especially in the Middle East and Iraq. Most of sulfate salts in fine aggregate are composed of calcium, magnesium, potassium and sodium sulfates. Calcium sulfates is the most common salt present in fine aggregate. It is usually finding as gypsum. It is difficult to obtain the specific sulfates content in fine aggregate within standard specifications. This research was conducted to investigate the effect of adding different contents of gypsum to fine aggregate as a replacement by weight on some properties of two types of concrete {self-compacted concrete (SCC) and high strength concrete (HSC)}. In these work three bases mixes of each type of concrete are used: mixes with different contents of metakaolin, mixes with different contents of gypsum and mixes incorporating different contents of metakaolin and gypsum. This study is devoted to determine the allowable content of sulfates in fine aggregate. Three levels of gypsum were tested (0.5, 1, 1.5) % by weight of fine aggregate and three levels of metakaolin were tested (5, 10, 15) % by the weight of cement. The experimental program is devoted to produce concrete with different levels of metakaolin and gypsum and determine its mechanical properties such as compressive strength and splitting tensile strength. The results arrived from this work show that the optimum gypsum content was 1.5% by weight of fine aggregates for mixes of SCC which gives increases in compressive strength and tensile strength, and 1% gypsum for mixes of HSC, results showed also that the metakaolin improved the properties of the two types of concrete and increased the loss which caused by sulfates. The best mix ever in SCC is 1% gypsum with 5% metakaolin, and 1% gypsum with 10% metakaolin for HSC.


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