EFFECTS OF REPLACING CEMENT BY DATE PALM TREES WASTES ON CONCRETE PERFORMANCE

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ahmad Salah Edeen Nassef ◽  
Kalifa Hamed AlMuqbali ◽  
Sheikha Mahmood Al Naqabi
Keyword(s):  
Compressive Strength ◽  
Date Palm ◽  
Cement Content ◽  
Concrete Strength ◽  
Palm Tree ◽  
Compression Tests ◽  
Tree Leaves ◽  
Concrete Compressive Strength ◽  
Sustainable Environment ◽  
Palm Trees

This paper was studying the effects of palm tree wastes on the behavior of the concrete to reduce cement content in the concrete to ensure a sustainable environment. Both fibers of palm tree and the ash of palm tree leaves are used in this study considering different percentages of palm tree wastes, which are replaced the cement, to investigate both of workability and strength of the concrete. Also, the combination of palm tree leaves ash and fibers of palm trees is investigated. The slump and compression tests are carried out to evaluate both workability and concrete strength. The palm fibers were reducing the workability of concrete at both of different percentage of replacement and different fiber lengths. The slump is reduced by 26.667% at 2 cm fibers length and it is completely lost at 5 cm length fibers at the same percentage of replacement of 5% of the cement content. The palm fibers were weakening concrete compressive strength at different percentages and different fiber lengths. Palm leaves ash was enhancing concrete workability and concrete compressive strength.

PENGKAJIAN KEKUATAN BETON STRUKTUR JEMBATAN PASCA KEBAKARAN

2013 ◽  
Vol 12 (3) ◽  
Author(s):  
Sudarmadi Sudarmadi
Keyword(s):  
Compressive Strength ◽  
Concrete Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Test Results ◽  
Concrete Compressive Strength ◽  
Strength Assessment ◽  
Concrete Testing

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.

scholarly journals Evaluation of Self-Compacting Concrete Strength with Non-Destructive Tests for Concrete Structures

2019 ◽  
Vol 9 (23) ◽  
pp. 5109 ◽  
Author(s):  
Miguel C. S. Nepomuceno ◽  
Luís F. A. Bernardo
Keyword(s):  
Compressive Strength ◽  
Concrete Strength ◽  
Surface Hardness ◽  
Pulse Velocity ◽  
Concrete Compressive Strength ◽  
Self Compacting Concrete ◽  
Coarse Aggregates ◽  
Pull Out ◽  
Concrete Maturity ◽  
Non Destructive

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.

scholarly journals Experimental study on the effect of concrete strength and corrosion level on bond between steel bar and concrete

2021 ◽  
Vol 72 (4) ◽  
pp. 498-509
Author(s):  
Vuong Doan Dinh Thien ◽  
Hung Nguyen Thanh ◽  
Hung Nguyen Dinh
Keyword(s):  
Compressive Strength ◽  
Bond Strength ◽  
Concrete Strength ◽  
Concrete Block ◽  
Bond Stress ◽  
Concrete Compressive Strength ◽  
Pull Out ◽  
Steel Bar ◽  
Stress Degradation ◽  
Slip Displacement

Corrosion of the steel reinforcement bars reduces the area of the steel bar and the bond stress between the steel bars and around concrete that decreases the capacity of concrete structures. In this study, the bond stress between steel bar with a diameter of 12mm and concrete was examined with the effect of different corrosion levels and different concrete grades. A steel bar was inserted in a concrete block with a size of 20×20×20cm. The compressive strength of concrete was 25.6MPa, 35.1MPa, and 44.1MPa. These specimens were soaked into solution NaCl 3.5% to accelerate the corrosion process with different corrosion levels in the length of 60mm. The pull-out test was conducted. Results showed that the bond strength of the corroded steel bar was higher than that predicted from CEB-FIP. Slip displacement and the range of slip displacement at the bond strength were reduced when the concrete compressive strength was increased. The rate of bond stress degradation occurred faster with the increment of the corrosion level when the concrete compressive strength was increased.

scholarly journals THE SUITABILITY OF SEAWATER ON CONCRETING IN THE NIGER – DELTA ZONE

2019 ◽  
pp. 39-48
Keyword(s):  
Compressive Strength ◽  
Niger Delta ◽  
Mathematical Theory ◽  
Regression Models ◽  
Cement Content ◽  
Suitable Condition ◽  
Maximum Level ◽  
Minimum Level ◽  
Concrete Compressive Strength ◽  
Factorial Regression

This study was carried out in order to determine the suitability or otherwise of seawater for concreting. The study was carried out using the Box-Wilson symmetric composite plan B3, comprising 15 experimental points with 3 levels of treatment each. In accordance with the principle of the mathematical theory of experiment, multi-factorial regression models were evolved. The cement content at maximum level[x1 (+), water content at the minimum level [x2 (-)] and retarding admixture at minimum level of treatment [x3(-)] proved to be the most suitable condition for concreting. The result as follows were; Concrete slump: 60mm, Concrete density: 2450g/cm3, Concrete compressive strength: 22.56N/mm2, 26.65N/mm2 and 30.09N/mm2 for 7days, 14days and 28 days, respectively.

scholarly journals The Effect of Soil Mineral Composition on the Compressive Strength of Cement Stabilized Rammed Earth

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 324 ◽  
Author(s):  
Piotr Narloch ◽  
Piotr Woyciechowski ◽  
Jakub Kotowski ◽  
Ireneusz Gawriuczenkow ◽  
Emilia Wójcik
Keyword(s):  
Compressive Strength ◽  
Mineral Composition ◽  
Cement Content ◽  
Rammed Earth ◽  
Compression Tests ◽  
Soil Mineral ◽  
Sem Images ◽  
Mineral Compositions ◽  
Strength Result ◽  
Distribution Water

Cemented stabilized rammed earth (CSRE) is a building material used to build load bearing walls from locally available soil. The article analyzes the influence of soil mineral composition on CSRE compressive strength. Compression tests of CSRE samples of various mineral compositions, but the same particle size distribution, water content, and cement content were conducted. Based on the compression strength results and analyzed SEM images, it was observed that even small changes in the mineral composition significantly affected the CSRE compressive strength. From the comparison of CSRE compressive strength result sets, one can draw general qualitative conclusions that montmorillonite lowered the compressive strength the most; beidellite also lowered it, but to a lesser extent. Kaolinite lightly increased the compressive strength.

Effect of coarse aggregate size on strength and workability of concrete

2006 ◽  
Vol 33 (2) ◽  
pp. 206-213 ◽  
Author(s):  
Peter J Tumidajski ◽  
B Gong
Keyword(s):  
Compressive Strength ◽  
Water Demand ◽  
Coarse Aggregate ◽  
Cement Content ◽  
Aggregate Size ◽  
Concrete Compressive Strength ◽  
Aggregate Fraction ◽  
Maximum Compressive Strength

The properties of concrete were studied when the proportions of 37.5 and 19.5 mm stone in the coarse aggregate were varied. With the cement content of 160 kg/m3 and the ratio of water/cement (w/c) greater than 0.9, the compressive strength is maximum at 25 percent by weight (w/o) of 37.5 mm stone. Conversely, for the cement content of 350 kg/m3 and w/c ratios of less than 0.50, maximum compressive strength is substantively reduced. For both 160 kg/m3 and 350 kg/m3 cement contents, workability improves slightly as the proportion of the 37.5 mm stone is increased. For 100 mm fixed slumps and cement content of less than 160 kg/m3, there was little change in compressive strength as the proportion of 37.5 mm stone increased. However, when cement content was increased from 190 to 350 kg/m3, maximum compressive strength was observed, which shifted downward from 50 w/o to 25 w/o of 37.5 mm stone. In general, to maintain a 100 mm slump, water demand decreased as the proportion of 37.5 mm stone in the coarse aggregate fraction increased.Key words: concrete, compressive strength, workability, slump, aggregate, size, cement.

Influence of Curing Pressure on Unconfined Compressive Strength of Cemented Clay

2018 ◽  
Vol 928 ◽  
pp. 263-268 ◽  
Author(s):  
Anuchit Uchaipichat
Keyword(s):  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Cement Content ◽  
Soft Clay ◽  
Peak Stress ◽  
Confining Pressure ◽  
Compression Tests ◽  
Unconfined Compression ◽  
Soil Cement ◽  
Curing Pressure

The soil-cement columns are generally installed and cured in the soft clay layers under confining pressure. The strength of the soil-cement columns may be influenced by confining pressure during curing period. In this study, the main objective was to study the influence of curing pressure on unconfined compressive strength of cemented clay. A series of unconfined compression tests was performed on a cement admixed clay sample cured under pressure values of 0 kPa (atmospheric pressure), 25kPa, 50kPa and 100 kPa using a typical unconfined compression equipment. The test samples with values of cement content of 0.5, 1.0 and 2.0 percent were cured for 28 days.The stress-strain curves obtained from all tests show a peak value of stress. The unconfined compressive strength or peak stress obviously increased with increasing cement content for all curing pressure conditions. It can be observed that the strength of samples gradually increased with curing pressure for cement content of 0.5 percent. For cement contents of 1.0 and 2.0 percent, the strengths of samples cured under pressures of 25 kPa dramatically increased from the strength of samples cured without pressure (0 kPa), however, the strengths of samples for curing pressures of 25, 50 and 100 kPa were not clearly different.

Analysis of the Impact of Concrete Compressive Strength Reduction in Joint Core Area on Super High-Rise Structures

2013 ◽  
Vol 438-439 ◽  
pp. 690-695
Author(s):  
Xiao Yu ◽  
Na Wu ◽  
Zhao Yang ◽  
Kai Xu
Keyword(s):  
Compressive Strength ◽  
Cross Sections ◽  
Concrete Strength ◽  
Nonlinear Finite Element ◽  
Core Area ◽  
Concrete Compressive Strength ◽  
Element Analysis ◽  
High Rise ◽  
The Impact ◽  
Joint Core Area

t is focused on a super high-rise building structure, of which the concrete compressive strength is reduced in joint core. The whole structure is calculated with program SATWE. Based on this calculation, integral stress analysis by MIDAS when concrete strength is reduced in joint core area and nonlinear finite element analysis by ANSYS on the joints of the worst cross-sections in the whole structure are developed. Thus the adverse effect of reduced concrete strength in joint core area on super high-rise structures is found out.

The Application of Bounded Normal Distribution in Statistics of Concrete Strength

2013 ◽  
Vol 671-674 ◽  
pp. 1641-1647
Author(s):  
Xu Yan ◽  
Yong Zhi Zuo ◽  
Qiao Zhi Lu ◽  
Da Huo ◽  
Ming Liu
Keyword(s):  
Compressive Strength ◽  
Normal Distribution ◽  
Goodness Of Fit ◽  
Concrete Strength ◽  
Concrete Compressive Strength ◽  
Mean Values ◽  
Coefficients Of Variations ◽  
Log Normal ◽  
Original Strength ◽  
Log Normal Distribution

23,037 values of concrete compressive strength from construction sites were obtained from Beijing Building Construction Research Institute from 2009-2012 by standard cubes testing method. The mean values, standard deviations, coefficients of variations, maxima and minima were derived from the original strength values analyzed and compared with the data in 1989. The results make up for the lack in C25/C30 and the maxima/minima of every strength class of concrete of the former data. Both the coefficients of variations and mean values have increased in recent years. The log-normal distribution commonly used in concrete compressive strength statistics is not that suitable for strength modeling for it is unbounded. So a bounded normal distribution was given in this paper. By Geary's test, the goodness-of-fit of bounded normal distribution is better than log-normal distribution has been proved.

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