scholarly journals Assessment of Changes in Compressive Strength of Deep Beam Elements Made by Pumping Self-Compacting Concrete Bottom-Up

Author(s):  
Piotr Dybel
2019 ◽  
Vol 9 (23) ◽  
pp. 5109 ◽  
Author(s):  
Miguel C. S. Nepomuceno ◽  
Luís F. A. Bernardo

Self-compacting concrete (SCC) shows to have some specificities when compared to normal vibrated concrete (NVC), namely higher cement paste dosage and smaller volume of coarse aggregates. In addition, the maximum size of coarse aggregates is also reduced in SCC to prevent blocking effect. Such specificities are likely to affect the results of non-destructive tests when compared to those obtained in NVC with similar compressive strength and materials. This study evaluates the applicability of some non-destructive tests to estimate the compressive strength of SCC. Selected tests included the ultrasonic pulse velocity test (PUNDIT), the surface hardness test (Schmidt rebound hammer type N), the pull-out test (Lok-test), and the concrete maturity test (COMA-meter). Seven sets of SCC specimens were produced in the laboratory from a single mixture and subjected to standard curing. The tests were applied at different ages, namely: 1, 2, 3, 7, 14, 28, and 94 days. The concrete compressive strength ranged from 45 MPa (at 24 h) to 97 MPa (at 94 days). Correlations were established between the non-destructive test results and the concrete compressive strength. A test variability analysis was performed and the 95% confidence limits for the obtained correlations were computed. The obtained results for SCC showed good correlations between the concrete compressive strength and the non-destructive tests results, although some differences exist when compared to the correlations obtained for NVC.


2017 ◽  
Vol 67 (325) ◽  
pp. 111 ◽  
Author(s):  
D. Burgos ◽  
A. Guzmán ◽  
K. M.A. Hossain ◽  
S. Delvasto

This study evaluates the use of large amounts of fine powders (fillers) derived from a Colombian volcanic material into the production of self-compacting concrete (SCC) for lower strength applications. The effects on SCC properties were studied with the incorporation of up to 50% of volcanic material of Tolima (MVT) as a partial substitute of the total weight of Portland cement. The workability was determined through slump flow, V-funnel, and L-box test. The compressive strength results were analyzed statistically by MINITAB. These demonstrated that 30% (by total weight of cementitious material) was the maximum allowable percentage of MVT to be used in the production of SCCs. Based on this, mechanical and permeability properties of SCC MVT 30% were evaluated at 28, 90 y 360 curing days. SCC MVT 30% exhibited compressive strength of 21 and 27 MPa after 28 and 360 days of curing, respectively.


2015 ◽  
Vol 05 (01) ◽  
pp. 131-138 ◽  
Author(s):  
Mohamed A. Ahmed ◽  
Yehia A. Hassanean ◽  
Kamal A. Assaf ◽  
Moustafa A. Shawkey

2018 ◽  
Vol 4 (4) ◽  
pp. 54
Author(s):  
Iis Nurjamilah ◽  
Abinhot Sihotang

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


Self compacting concrete achieves compaction by itself without using mechanical vibration techniques. Addition of fibers to SCC results in increased performance mainly in flexure, and also in compressive strength. In this study both the flow and strength properties of single Fiber and blended fiber reinforced self compacting concrete are examined in comparison with control self compacting concrete. crimpled steel fibers having size of 0.45mm diameter x 12.5mm length (aspect ratio 27.7) and 0.45mm diameter x 20 mm length (aspect ratio 44.44) are used in the SCC mix at various percentages by weight of cement i.e. 0%, 2%, 4% and 6%. From the obtained results it can be seen that there is aadverse affect on flow properties. There is a moderate increase in the compressive strength, split tensile strength and considerable increase in the flexural strength of the self compacting concrete using the blended fibers at different percentages i.e. at 2% and 4%, when compared to the single fiber reinforced self compacting concrete.


2014 ◽  
Vol 11 (4) ◽  
pp. 323-330 ◽  
Author(s):  
S. Arivalagan

The present day world is witnessing the construction of very challenging and difficult civil engineering structures. Self-compacting concrete (SCC) offers several economic and technical benefits; the use of steel fiber extends its possibilities. Steel fiber acts as a bridge to retard their cracks propagation, and improve several characteristics and properties of the concrete. Therefore, an attempt has been made in this investigation to study the Flexural Behaviour of Steel Fiber Reinforced self compacting concrete incorporating silica fume in the structural elements. The self compacting concrete mixtures have a coarse aggregate replacement of 25% and 35% by weight of silica fume. Totally eight mixers are investigated in which cement content, water content, dosage of superplasticers were all constant. Slump flow time and diameter, J-Ring, V-funnel, and L-Box were performed to assess the fresh properties of the concrete. The variable in this study was percentage of volume fraction (1.0, 1.5) of steel fiber. Finally, five beams were to be casted for study, out of which one was made with conventional concrete, one with SCC (25% silica fume) and other were with SCC (25% silica fume + 1% of steel fiber, 25% silica fume + 1.5% of steel fiber) one with SCC (35% silica fume), and other were SCC (35% Silica fume + 1% of steel fiber, 35% Silica fume + 1.5% of steel fiber). Compressive strength, flexural strength of the concrete was determined for hardened concrete for 7 and 28 days. This investigation is also done to determine the increase the compressive strength by addition of silica fume by varying the percentage.


2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Fatih Özcan ◽  
Halil Kaymak

In this work, utilization of metakaolin (MK) and calcite (C), working reversely in workability aspect, as mineral admixture in self-compacting concrete (SCC), was investigated. MK and C replaced cement in mass basis at various replacement ratios, separately and together. In total, 19 different SCCs were produced. Binder content and water to binder ratio were selected as 500 kg/m3 and 0.4, respectively. Workability tests including slump flow, T50, L-box, and V-funnel tests were performed. Consistency and setting times of binder paste were measured. While replacement of MK with cement increased the amount of plasticiser requirement, calcite worked reversely and decreased it. Reverse influence of MK and C on plasticiser requirement of SCC made possible to produce SCC at total 45% replacement ratio of MK and C together. Samples of SCC were cured in water at 20°C temperature. Compressive strengths of SCC samples were measured up to six months to evaluate the influence of MK and C, separately and together. Ultrasonic pulse velocity, abrasion, and capillary water absorption values of samples were determined at specified age. MK inclusion in concrete reduces workability, while C inclusion increases it. C and MK inclusion together remedied workability of concrete and enabled to produce SCC with high volume of admixtures. Furthermore, C incorporation increased one-day compressive strength, while MK incorporation reduced it in comparison with control concrete. In long term, C inclusion reduced compressive strength; however, MK inclusion increased it. C inclusion remedied one-day strength of concrete when it was used together with MK. MK inclusion remedied long-term compressive strength when it was used together with C and enabled to produce high-strength SCC with high volume of admixtures. SCC containing MK and C together showed better durability-related property.


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