scholarly journals Assessment of the influence of fly ash additive on the tightness of concrete with furnace cement CEM IIIA 32,5N

2017 ◽  
Vol 66 (4) ◽  
pp. 153-164
Author(s):  
Anna Szcześniak ◽  
Jacek Zychowicz ◽  
Adam Stolarski

The analysis of influence of fly ash additive to concrete on the basis of cement CEM IIIA 32,5 N on the tightness and strength was presented in the paper. Researches were carried out for three types of concrete made with the use of CEM IIIA 32,5N LH HSR NA cement. The basic recipe of concrete does not contain the additive of fly ash, while two other concretes contain the fly ash additive in an amount of 25% and 33% of the cement mass. Laboratory investigations of the concrete samples were carried out under conditions of long-term maturation in the range of the water tightness and the depth of water penetration in concrete, compressive strength and tensile strength of concrete at splitting. Keywords: concrete testing, furnace cement, fly ash additive, water tightness of concrete, strength of concrete.

2013 ◽  
Vol 12 (3) ◽  
Author(s):  
Sudarmadi Sudarmadi

In this paper a case study about concrete strength assessment of bridge structure experiencing fire is discussed. Assessment methods include activities of visual inspection, concrete testing by Hammer Test, Ultrasonic Pulse Velocity Test, and Core Test. Then, test results are compared with the requirement of RSNI T-12-2004. Test results show that surface concrete at the location of fire deteriorates so that its quality is decreased into the category of Very Poor with ultrasonic pulse velocity ranges between 1,14 – 1,74 km/s. From test results also it can be known that concrete compressive strength of inner part of bridge pier ranges about 267 – 274 kg/cm2 and concrete compressive strength of beam and plate experiencing fire directly is about 173 kg/cm2 and 159 kg/cm2. It can be concluded that surface concrete strength at the location of fire does not meet the requirement of RSNI T-12-2004. So, repair on surface concrete of pier, beam, and plate at the location of fire is required.


The present study appraises the recitals of carboxylic acid- based admixture to increase concrete water tightness and self-sealing capacity of the cement and geopolymer concrete. Outcomes of the previous studies in particular, adding 1% by cement mass of the carboxylic polymer reasons for reduction in the water dispersion under pressure of 7-day wet cured concrete by 50% associated to that of the conforming reference concrete. At 7 days, M4 mix compressive strength is about 43.5% less than M3 mix. The compressive strength of M4 increases and is about 37.6% less than M3 mix at 28 days of curing. At 7 days, M4 mix split tensile strength is about 17.5% less than M3 mix (cement concrete with 0.45 w/c ratio). The split tensile strength of M4 declines and is about 42.3% less than M3 mix at 28 days of curing. The strength of the geopolymer concrete tends to increase as the time period increases due to the presence of fly ash in it. So it is expected that geopolymer concrete will give more strength than cement concrete in long term with the presence of carboxylic acid


2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Weilai Yao ◽  
Shiyong Jiang ◽  
Wei Fei ◽  
Tao Cai

Compressive strength and tensile strength are important mechanical properties of concrete. The long-term strength of concrete under real service environment is an important parameter when evaluating existing buildings, which should also be properly considered in structural design. In this study, the relationship between compressive and splitting tensile strength of old concrete existing for long period under marine environment was investigated. At a deserted harbour, concrete cores samples were drilled by pairs in site. For each pair of samples, the two cores were drilled from the adjacent location and conducted to compressive, splitting tensile test, respectively. 48 compressive and splitting tensile strengths were finally obtained. From the test results, tensile strength presents general uptrend with compressive strength, and the two parameters are well positively correlated. Exponential model generally recommended by building codes or literatures is still capable of describing the relationship between compressive and tensile strength of old deteriorated concrete, when function parameters are properly determined. Based on statistical theory and the experimental result of this study, a method for predicting long-term tensile strength of concrete is developed and an example is given, which may provide a potential way to estimate long-term concrete strength under real marine environment.


2014 ◽  
Vol 897 ◽  
pp. 301-304
Author(s):  
Ester Helanová ◽  
Rostislav Drochytka ◽  
Radek Janovský

The fly ash aerated concrete is a modern material combining high use value with environmental aspects of its production. It is mainly an utilisation of secondary raw materials with related minimum consumption of natural resources. The resulting properties the aerated concrete product obtains by autoclaving during which a complete line of calcium hydro silicates are formed due to occurring hydrothermal reaction and tobermorite mineral is the most important one. This mineral has a significant influence principally on aerated concrete strength. This article thus verifies the autoclaving time influence on tobermoritic phase developments and to this related compressive strength of the fly ash aerated concrete.


Author(s):  
Masri A Rivai ◽  
Sudirman Kimi ◽  
Revisdah Revisdah

In this study the author take Fly Ash and Powder Glass as an added ingredient in the concrete mix. This research intend to know the effect of Fly Ash and Powder Glass on K-300 concrete compressive strenght.This study uses cube-shaped specimens with the siza of 15 x 15 x 15. The total of test specimens in this study as much as 45 sample, each 9 seal of test specimens in 5 condition that is normal, concrete + fly ash 5% + glass powder 18%, concrete + fly ash 5% + glass powder 21%, concrete + fly ash 5% + glass powder 24%, concrete + fly ash 5% + glass powder 27%.After concrete compressive strenght test, the concrete strength og the concrete at age 3, 7 and 28 days with normal condition at 3 days age aqual to 139.26 Kg/Cm2, at age 7 day equal to 202.17 Kg/Cm2 and age 28 day of 307.01 Kg/Cm2. And the value of compressive strength of concrete characteristic with the use of Fly Ash 5% + glass powder 18% has the highest value of concrete compressive strength that is at 3 days age of 151.13 Kg/Cm2, 7 day age equal to 21175 Kg/Cm2 and age 28 is 312.81 Kg/Cm2 . These result exceed the copressive strength values of normal concrete characteristic and show that fly ash and glass powder can increase the compressive of the concrete.


2018 ◽  
Vol 9 (2) ◽  
pp. 67-73
Author(s):  
M Zainul Arifin

This research was conducted to determine the value of the highest compressive strength from the ratio of normal concrete to normal concrete plus additive types of Sika Cim with a composition variation of 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1 , 50% and 1.75% of the weight of cement besides that in this study also aims to find the highest tensile strength from the ratio of normal concrete to normal concrete in the mixture of sika cim composition at the highest compressive strength above and after that added fiber wire with a size diameter of 1 mm in length 100 mm with a ratio of 1% of material weight. The concrete mix plan was calculated using the ASTM method, the matrial composition of the normal concrete mixture as follows, 314 kg / m3 cement, 789 kg / m3 sand, 1125 kg / m3 gravel and 189 liters / m3 of water at 10 cm slump, then normal concrete added variations of the composition of sika cim 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1.5%, 1.75% by weight of cement and fiber, the tests carried out were compressive strength of concrete and tensile strength of concrete, normal maintenance is soaked in fresh water for 28 days at 30oC. From the test results it was found that the normal concrete compressive strength at the age of 28 days was fc1 30 Mpa, the variation in the addition of the sika cim additive type mineral was achieved in composition 0.75% of the cement weight of fc1 40.2 Mpa 30C. Besides that the tensile strength test results were 28 days old with the addition of 1% fiber wire mineral to the weight of the material at a curing temperature of 30oC of 7.5%.


2014 ◽  
Vol 53 (3) ◽  
pp. 627-642 ◽  
Author(s):  
Ahmed M. Diab ◽  
Hafez E. Elyamany ◽  
Abd Elmoaty M. Abd Elmoaty ◽  
Ali H. Shalan

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.


2015 ◽  
Vol 773-774 ◽  
pp. 949-953 ◽  
Author(s):  
Izni Syahrizal Ibrahim ◽  
Wan Amizah Wan Jusoh ◽  
Abdul Rahman Mohd Sam ◽  
Nur Ain Mustapa ◽  
Sk Muiz Sk Abdul Razak

This paper discusses the experimental results on the mechanical properties of hybrid fibre reinforced composite concrete (HyFRCC) containing different proportions of steel fibre (SF) and polypropylene fibre (PPF). The mechanical properties include compressive strength, tensile strength, and flexural strength. SF is known to enhance the flexural and tensile strengths, and at the same time is able to resist the formation of macro cracking. Meanwhile, PPF contributes to the tensile strain capacity and compressive strength, and also delay the formation of micro cracks. Hooked-end deformed type SF fibre with 60 mm length and fibrillated virgin type PPF fibre with 19 mm length are used in this study. Meanwhile, the concrete strength is maintained for grade C30. The percentage proportion of SF-PPF fibres are varied in the range of 100-0%, 75-25%, 50-50%, 25-75% and 0-100% of which the total fibre volume fraction (Vf) is fixed at 0.5%. The experimental results reveal that the percentage proportion of SF-PPF fibres with 75-25% produced the maximum performance of flexural strength, tensile strength and flexural toughness. Meanwhile, the percentage proportion of SF-PPF fibres with 100-0% contributes to the improvement of the compressive strength compared to that of plain concrete.


2013 ◽  
Vol 438-439 ◽  
pp. 30-35 ◽  
Author(s):  
Nirdosha Gamage ◽  
Sujeeva Setunge ◽  
Kasuni Liyanage

The Victoria State of Australia has the second largest reserves of brown coal on earth, representing approximately 20% of the worlds reserves, and at current use, could supply Victoria with its energy for over 500 years. Its combustion, annually, yields up to 1.3 million tonnes of fly ash, which is largely use for land-fills. Disposal of fly ash in open dumps cause massive environmental problems such as ground water contamination that may create various health problems. This study focuses on the usability of brown coal fly ash to develop a sustainable building material. A series of laboratory investigations was conducted using brown coal fly ash combined with cement and aggregate to prepare cold pressed samples aiming to test their properties. Initial results indicate that compressive strength satisfies minimum standard compressive strength required for bricks or mortar.


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