scholarly journals Concrete with Reused Concrete Sand

2019 ◽  
Vol 8 (6) ◽  
pp. 4868-4873
Keyword(s):  
Elastic Modulus ◽  
Compression Strength ◽  
Drying Shrinkage ◽  
Shrinkage Strain ◽  
Ordinary Concrete ◽  
Mixed Concrete

This paper examines the impacts of substitution of reused concrete sand (RCS) with sands, on the new and hardened physiognomies of concrete. the property of RCS blended concrete was examined and likened with ordinary concrete of 40 MPa compression strength. the physiognomies of RCS concrete vary from ordinary concrete arranged with characteristic sand, as an outcome of the quality of connected mortar, old cement glue, and more fines. the outcomes demonstrate that the RCS concrete demonstrations tantamount workability in contrast with ordinary concrete. the mechanical physiognomies (compressive, flexure, split tensile and elastic modulus) of concrete developed with RCS was lower in compression to ordinary concrete however worthy up to 60percentage RCS in the blend. The drying shrinkage strain of 100percentage RCC mixed concrete at twenty-eight days was watched twice in compression to controlled concrete and it demonstrated more abrasion value in that comparison and furthermore concrete developed with 100 percent RCS indicated 41percentage and 11.3percentage lower in sorption value at ahead of schedule and later age organize individually in that examination.

Relationship between Drying Shrinkage Strain of Concrete and Quality of Coarse Aggregate

2020 ◽  
Vol 58 (3) ◽  
pp. 223-228
Author(s):  
H. Yamada ◽  
H. Katahira ◽  
H. Watanabe
Keyword(s):  
Coarse Aggregate ◽  
Drying Shrinkage ◽  
Shrinkage Strain

scholarly journals Dimensional Stability of SBR-Modified Cementitious Mixtures for Use in 3D Additive Construction

2019 ◽  
Vol 9 (16) ◽  
pp. 3386 ◽  
Author(s):  
Kwan Kyu Kim ◽  
Jaeheum Yeon ◽  
Hee Jun Lee ◽  
Jung Heum Yeon
Keyword(s):  
Thermal Expansion ◽  
Elastic Modulus ◽  
Dimensional Stability ◽  
Coefficient Of Thermal Expansion ◽  
Construction Material ◽  
Drying Shrinkage ◽  
Shrinkage Strain ◽  
Thermal Shrinkage ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber

This study experimentally investigated the dimensional stability of SBR (styrene butadiene rubber)-modified cementitious mixtures in order to determine whether their properties are sustainable as a 3D additive construction material. Dimensional stability refers to resistance to material deformation caused by changes in internal relative humidity and temperature. Hence, drying and thermal shrinkage, which are the primary factors affecting dimensional stability, were tested. The mixing ratio of SBR-modified cementitious mixtures was determined based on a predetermined optimal flow of 70% ± 1% applicable for 3D additive construction applications. The results of this study showed that the elastic modulus, and drying shrinkage strain, excluding the coefficient of thermal expansion, all significantly improved as the SBR/cement ratio increased. In particular, drying shrinkage can be a disadvantage in 3D additive construction because drying in the printed mixtures is rapid due to the large specific exposure area of moldless construction. Consequently, mitigating drying shrinkage is very important. The elastic modulus, drying shrinkage, and coefficient of thermal expansion were all found to be associated with the dimensional stability obtained in this study. It was concluded that using SBR-modified cementitious mixtures was advantageous in terms of dimensional stability.

scholarly journals Development of Flotation Device for Removing Unburnt Carbon in Fly Ash for Use in Hardened Cementitious Materials

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6517
Author(s):  
Hangwei Lin ◽  
Koji Takasu ◽  
Hidehiro Koyamada ◽  
Hiroki Suyama
Keyword(s):  
Elastic Modulus ◽  
Fly Ash ◽  
Drying Shrinkage ◽  
Cementitious Materials ◽  
Unburned Carbon ◽  
Ordinary Concrete ◽  
Circulating Water ◽  
Micro Bubble ◽  
Concrete Mixer ◽  
Flotation Method

The unburned carbon in fly ash inhibits the performance of concrete. A device using the flotation method to remove unburned carbon in fly ash was developed, and the operating condition of the device was experimentally examined. According to the results, the device was able to remove unburnt carbon from fly ash by using the installed micro bubble nozzles and a whirl-type pump. The removal efficiency of unburnt carbon improved when prior forced stirring was carried out by a concrete mixer for 3 min, and a scavenger was added into the fly ash slurry at a density of about 60 wt%. It has also been confirmed that the method of circulating water is more effective than the method of not circulating water. The elements of the modified fly ash slurry (MFAS) have also been experimentally confirmed as not being too different from untreated fly ash, except for the fact that the content of unburned carbon is reduced. The compressive strength and drying shrinkage characteristics of concrete made with MFAS were investigated. The use of MFAS will reduce the performance of concrete compared to that of ordinary concrete. This shows that in a certain range (15–30%), the influence of MFAS on drying shrinkage is constant. The static elastic modulus and dynamic elastic modulus were also investigated. The above results show that the application of MFAS prepared by the flotation method to concrete is feasible.

Experimental Study of Frost-Resistance Properties of Silica Fume Concrete

2014 ◽  
Vol 584-586 ◽  
pp. 1626-1629 ◽  
Author(s):  
Zhi Gang Yin ◽  
Jun Feng ◽  
Shu You Huang ◽  
Bing Fang Zhao
Keyword(s):  
Elastic Modulus ◽  
Silica Fume ◽  
Frost Resistance ◽  
Dynamic Elastic Modulus ◽  
Test Results ◽  
Change Rate ◽  
Ordinary Concrete ◽  
Thawing Cycle ◽  
Different Content

The frost resistance of low strength concrete is researched. In order to evaluate the effect of different content of silica fume on frost resistance，the quality of the cement 6%, 9%, 12% silica fume are respectively added into concrete. Freezing-thawing test results show that: the silica fume concrete has good frost resistance. Content of silica fume on concrete is not almost effect to quality loss rate. In 0-250 times of freezing-thawing cycle range, it is smaller that relative dynamic elastic modulus change rate. Relative dynamic elastic modulus of ordinary concrete decreases rapidly after 250 times of freezing-thawing cycle while dynamic elastic modulus decrease rate of the silica fume concrete tends to slow. The freezing -thawing cycles up to 350 times, silica fume concrete relative dynamic elastic modulus is 1.5 times that of ordinary concrete that show the silica fume concrete frost resistance is better than that of ordinary concrete.

Quality of wheat breads enriched with flour from germinated amaranth seeds

2021 ◽  
pp. 108201322110165
Author(s):  
Luciano M Guardianelli ◽  
María V Salinas ◽  
María C Puppo
Keyword(s):  
Relaxation Time ◽  
Elastic Modulus ◽  
Wheat Flour ◽  
Specific Volume ◽  
Bread Quality ◽  
Maximum Volume ◽  
High Area ◽  
Amaranth Flour ◽  
Fermentation Parameters

Amaranth flour from germinated (GA) and non-germinated (A) seeds (0%-C, 5%, 15%, 25%) were mixed with wheat flour for breadmaking. Fermentation parameters of dough (time-tf, maximum volume-Vmax) were obtained. Specific volume (Vsp) of breads, crust color, texture and relaxation of crumb were analyzed. A high amount of germinated amaranth flour decreased Vmax and increased tf, obtaining breads with low Vsp and darkness crust. A firmed and chewy crumb, although with a more aerated structure (high area occupied by alveoli) was obtained. The GA25 bread presented the softer crumb. The elastic modulus-E1 of crumb increased and the relaxation time-T1 decreased with higher amounts of amaranth flour, suggesting the formation of a more structured crumb; mainly in the case of non-germinated amaranth flour. Wheat flour resisted the inclusion of 25% of germinated amaranth seeds (GA25) without substantial changes in bread quality.

scholarly journals Use the Polymer Concrete as a Substitute for Ordinary Concrete by Improving of Acoustic and Thermal Insulation With Suitable Cost

2017 ◽  
Vol 1 (2) ◽  
pp. 650-661
Author(s):  
Amer M. Ibrahim ◽  
Ali Adwan Hmood ◽  
Noor Al Huda H. Ahmed
Keyword(s):  
Thermal Conductivity ◽  
Compression Strength ◽  
Chemical Interaction ◽  
Economic Feasibility ◽  
Polymer Concrete ◽  
Light Weight ◽  
Novolac Resin ◽  
Ordinary Concrete ◽  
Acoustic Insulation ◽  
Light Weight Aggregate

The purpose of this study is to examine the effect of adding novolac resin by different volumetric percentages to concert as a light weight aggregate In addition to the economic feasibility of the use of these concrete in the field of build and construction .they investigated tht the compression strength, thermal conductivity, acoustic insulation and densities. The results showed ultimate compression strength and acoustic insulation by melting novolac and added to the cement and sand as a polymer concrete in the hot state (by melting novoac >90c).However added novolac resin as aggregate in the cold state to the concrete increase thermal conductivity and increasing compression strength and acoustic insulation .This results gained by chemical interaction of novolac and cement.  

scholarly journals ON THE ROLE OF HISTOMORPHOMETRIC (STEREOLOGICAL) MICROSTRUCTURE PARAMETERS IN THE PREDICTION OF VERTEBRAE COMPRESSION STRENGTH

2019 ◽  
Vol 38 (1) ◽  
pp. 63 ◽  
Author(s):  
Leszek Karol Wojnar ◽  
Aneta Gądek-Moszczak ◽  
Jacek Pietraszek
Keyword(s):  
Compression Strength ◽  
Correlation Coefficients ◽  
Diagnostic Techniques ◽  
Micro Ct ◽  
Compression Tests ◽  
Mineral Density ◽  
3D Images ◽  
Microstructure Parameters

The well-documented relation between bone mineral density (BMD) and bone compression strength constitutes the basis for osteoporosis diagnostics and the assessment of fracture risk. Simultaneously, this relation demonstrates a considerable scatter of results as bones of identical mineral density may have significantly different properties. The experimentally confirmed theorem that two materials or tissues of identical microstructure have identical properties leads to the evaluation of various quantitative stereological parameters (also referred to in biomedicine as histomorphology). These parameters, obtained from analysis of 2D or 3D images, have been used in numerous attempts to explain changes in bone strength. Although numerous correlation dependencies, often with high correlation coefficients, were evaluated, we do not know which parameters are worth evaluating, and there is no physical interpretation of these relations. An extended statistical analysis was accomplished on the basis of analysis of 3D images from 23 lumbar (L3) vertebrae scanned with micro-CT and the results of subsequent compression tests. A new parameter called SDF (structure destruction factor) was proposed in order to characterise the quality of 3D trabecular structures, and its significance was demonstrated. The final correlation function, which uses only three stereological parameters, made it possible to predict compression strength with considerable precision. The estimated values correlated very well with the apparent values (correlation coefficient r=0.96). Finally, the stereological parameters most suitable for characterisation of bone compression strength were chosen and a mechanism responsible for the changes in mechanical properties was proposed. The results obtained defined the necessary improvements in diagnostic techniques that would allow for more efficient quantitative microstructure evaluation and guidelines on how to improve treatment of patients with weakened bones.

scholarly journals PENENTUAN SIFAT MEKANIS DAN FISIS BATU BATA DENGAN PENAMBAHAN ARANG TEMPURUNG KELAPA ASAL ALOR

2018 ◽  
Vol 3 (1) ◽  
pp. 80-85
Author(s):  
Ernawati Kawa ◽  
Minsyahril Bukit ◽  
Albert Zicko Johannes
Keyword(s):  
Mechanical Properties ◽  
Physical Properties ◽  
Compression Strength ◽  
Physical And Mechanical Properties ◽  
Strength Test ◽  
Coconut Shell ◽  
Mechanical And Physical Properties ◽  
Maximum Limit

Abstrak Telah dilakukan penelitian tentang penentuan sifat mekanis dan fisis batu bata dengan penambahan tempurung kelapa asal alor. Penenlitian ini bertujuan mengetahui kualitas batu bata yang memenuhi standar kelayakan sebagai bahan konstruksi dengan penambahan arang tempurung kelapa aal alor dengan presentasi 0%, 5%, 10%, 15% terhadap tanah liat (lempung). Batu bata dicetak dengan prosedur pemadatan, pengringn dan pembakaran. Setelah prosedur pencetakkan selesai kemudian di lanjutkan dengan pengujian sefat mekanis dan sifat fisis, yaitu uji kuat tekan (compression strength), densitas (density), porositas (porosity) hasil  kuat tekan batu bata didapatkan berdasarkan pengujian: a) uji kuat tekan, batu bata tanpa penambahan (0%) : 4,94 meemenuhi standar kuat tekan kelas 50 (SNI 15-2094-2000), b) uji porositas, batu bata 0% dan 5% : 3,82% dan 17,93% memenuhi standar porositas dengan batas maksimum 20% (SNI 15-2094-2000) dan uji densitas, batu bata tidak ada yang memenuhi standar (SII 0021-1978) Kata kunci: sifat mekanis, sifat fisis, tempurung kelapa, densitas, porositas, kuat tekan Abstract A research had been conducted to determine physical and mechanical properties of the bricks with the addition coconut shell charcoal from alor. This research aims at the quality of the bricks to meet the standars of eligibility as a contruction material. The addition of coconut shell charcoal is variate with the presentage 0%, 5%, 10%, 15% to the clay mass. The brick being printed with procedure compaction, drying, and baking. After the printing procedure is done then next is testing the mechanical and physical properties, that is compression strength test, density test, and porosity test. The brick quality result is obtained based on the test: a) compression strength test, the brick without addition (0%) : 4,94  (SNI 15-2094-2000) is comply with the standard compression strength the class 50 , b) porosity test, the brick 0% and 5% (3,82% and 17,93%) meet the standard with the maximum limit 20% ( SNI 15-2094-2000)  , and c) density test, every bricks does not meet the standard (SII 0021- 1978). Keywords: mechanical properties, physical properties, coconut shell, density, porosity, compression strength

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