scholarly journals Assessment of the early-age compressive strength of concrete

2021 ◽  
Vol 20 (2) ◽  
pp. 005-014
Author(s):  
Dorota Michałowska-Maziejuk ◽  
Barbara Goszczyńska

This paper analyses the results of concrete compressive strength tests on cubic samples with different w/c ratios during the early stage of hardening (at 7, 14, and 28 days). Statistical and strength parameters were assessed and the quality of the concrete was estimated. The expected concrete grade, C25/30, was confirmed against the formulation provided by the prefabrication plant. Then, the amount of individual constituents was adjusted to obtain the target grade of concrete, i.e., C20/25. The concrete grade was estimated based on concrete strength parameters measured at three time points and compared with the expected 28-day strength values determined as per Eurocode 2 and with the concrete grade defined by these values. The paper also provides an overview of the most widely used methods of testing concrete compressive strength.

2019 ◽  
Vol 9 (2) ◽  
pp. 47-54
Author(s):  
Fepy Supriani ◽  
Mukhlis Islam

Concrete strength is influenced by several variables, among others by its constituent material, mix design, workmanship, and curing. The objective of concrete curing is to maintain the concrete in certain conditions after the dismantling of the formwork hence the optimization of concrete strength can be achieved close to the designed strength. This study aims to determine the effect of concrete curing on its compressive strength. Designed concrete compressivestrength of 20 MPa with slump values of 60-100 mm to be used. The specimens are cube-shaped with 15 cm dimension. Concrete compressive strength tests were conducted at 28 days and 56 days of concrete age. The types of concrete curing consist of 9 variations, i.e., not treated, water immersed and water sprinkling. Optimum 28 days age of compressive strength of concrete obtained from specimens that immersed in fresh water, which was 31,3 MPa. The concretespecimens that were put outdoor without any curing and treatment generates second highest compressive strength value of 28.6 MPa. The 28 days age of concrete compressive strength values cured with water sprinkling with addition of burlap wrapping are still under the compressive strength of uncured concrete. Significant changes to the strength of cured concrete occurred at age of 56 days and uncured concrete strength decreased up to 19%. The optimum increase occurred in concrete cured with burlap sack wrapping and water sprinkling that was conducted routinely for 3 days by 27,84%. With increasing age (durability) the treated concrete has better strength.


2014 ◽  
Vol 897 ◽  
pp. 234-237
Author(s):  
Adam Hubáček

Sprayed concrete is widely applied in spite of developing economical crisis. The paper focuses on possibilities of manufacture and testing basic physical parameters of sprayed concrete prepared in common laboratory mixer and compacted by vibration combined with defined level of pressure. The aim is assessment of basic properties of sprayed concrete: compressive strength of early age sprayed concrete, strength of drilled core, assessment of homogeneity and density of concrete, determination of elasticity modules. On the basis of results, possible correlation relationships will be predicted for this manufacture process and for common application by means of spraying onto a structure.


Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 544
Author(s):  
Justyna Czajkowska ◽  
Maciej Malarski ◽  
Joanna Witkowska-Dobrev ◽  
Marek Dohojda ◽  
Piotr Nowak

Contact of concrete with aggressive factors, technological structures, reduces their durability through microstructural changes. This work presents the results of research on determining the influence of post grit chamber sewage and sewage from the active sludge chamber in three different environments, i.e., acidic, neutral, and alkaline, on the structure and compressive strength of concrete. Compressive strength tests were carried out after 11.5 months of concrete cubes being submerged in the solutions and compared. To complete the studies, the photos of the microstructure were done. This made it possible to accentuate the relationship between the microstructure and performance characteristics of concrete. The time of storing the cubes in both acidic environments (sewage from post grit chamber and active sludge chamber) has a negative influence on their compressive strength. The compressive strength of cubes decreases along with the time. Compressive strength of cubes increases with increasing pH of the environment.


2017 ◽  
Vol 6 (1) ◽  
pp. 30-40
Author(s):  
Fauzi Rahman ◽  
Fathurrahman Fathurrahman

In 2015 the total area of oil palm plantations in Kalimantan reached 3.47 million Ha with a production of 8.12 million tons per year. Solid waste is in the form of fresh fruit bunches and palm shells. The result of combustion of oil palm shell waste in the form of boiler crust ash is a waste that has chemical elements SiO2, Al2O3, and CaO, with the content of these compounds can affect the strength of the concrete and can increase its strength. In this study, the quality of the concrete mix planned at 28 days is 23 MPa. Concrete testing included compressive strength tests carried out at 3 days, 7 days, 14 days, 28 days, 42 days and 56 days. Before making concrete samples, the mortar compressive strength is tested first by varying the boiler crust ash content by 0%, 15%, 25%, 35%, and 50% to obtain the optimum mixture. Based on the results of the analysis of compressive strength mortar obtained the optimum mixture of 15% for the manufacture of concrete that will be compared with normal concrete. The compressive strength of concrete with the optimum mixture at 28 days is 24.44 Mpa more than the compressive strength of the 23 Mpa plan. Concrete that has the highest compressive strength occurs at the age of 56 days is concrete with the normal mixture with a compressive strength of 34.44 Mpa higher than the compressive strength of concrete with an optimum mixture of 15% boiler crust ash which is 28.51 MPa.


2018 ◽  
Vol 8 (1) ◽  
pp. 32-41
Author(s):  
Muhamad Nasrulloh,

Concrete is a building material widely used in construction projects. In principle to create concretewith very good quality by the quality of its constituents of fine aggregate (sand), coarse aggregate,semen, and air, and the way it works. The fine aggregate (sand) as the base material for concretemanufacture is required in determining the quality of the concrete, since the aggregate is a fillerbound by cement and water into a solid mass, the quality of fine aggregate luminaire (sand) directlyaffects the quality of the concrete. The fine aggregate (sand) used in this study came from 3samples in Blitar area, ie 1 sample from Kelud mountain, 2 samples from Kali Putih, and 3 samplesfrom Brantas River. Location of research at the Laboratory Structural Civil Engineering UniversityTribhuwana Tunggadewi Malang. The method used in this study using laboratory experiments andguided on SNI 03-06912000. After a fine aggregate study of 3 samples in Bitarit obtained theaverage compressive strength test, samples of 1 fine aggregate (sand) of Kelud mount recordedaverage of concrete compressive strength of 7,802 Mpa (highest), sample 2 of fine aggregate ( sand)of Kali Putih resulted in average concrete strength test of 3.208 Mpa (lowest), and a sample of 3 fineaggregate (sand) of Brantas river yielded average concrete strength test of 3,272 MPaBeton merupakan material bahan bangunan yang banyak dipergunakan dalam pelaksanaan proyekkonstruksi. Pada prinsipnya untuk mendapatkan beton dengan kualitas yang baik sangatdipengaruhi oleh kualitas dari bahan – bahan penyusunnya yaitu agregat halus (pasir), agregat kasar,semen, dan air, serta cara pengerjaannya. Agregat halus (pasir) sebagai bahan dasar untukpembuatan beton memegang peranan penting dalam menentukan mutu beton, karena agregatmerupakan bahan pengisi yang diikat oleh semen dan air menjadi massa padat, sehingga kualitasagregat halus (pasir) mempengaruhi langsung terhadap mutu beton. Agregat halus (pasir) yangdibahas pada penelitian ini berasal dari 3 sampel di wilayah Blitar, yaitu sample 1 dari gunung Kelud,sampel 2 dari kali Putih, dan sampel 3 dari sungai Brantas. Lokasi penelitian di LaboratoriumStruktur Teknik Sipil Universitas Tribhuwana Tunggadewi Malang. Metode yang digunakan dalampenelitian ini menggunakan eksperimen laboratorium dan berpanduan pada SNI 03-06912000.Setelah dilakukan penelitian agregat halus dari 3 sampel diBlitar mendapatkan hasil uji kuat tekanrata -rata yaitu, sample 1 agregat halus (pasir) gunung Kelud menghasilkan rata – rata uji kuat tekanbeton sebesar 7,802 Mpa (tertinggi), sample 2 agregat halus (pasir) Kali Putih menghasilkan rata –rata uji kuat tekan beton sebesar 3,208 Mpa (terendah), dan sample 3 agregat halus (pasir) sungaiBrantas menghasilkan rata – rata uji kuat tekan beton sebesar 3,272 Mpa


2018 ◽  
Vol 8 (1) ◽  
pp. 27-36
Author(s):  
M. Esmailpour ◽  
K. Rahmani ◽  
S. Piroti

Abstract The use of various additives (admixtures) in concrete and cement products has been considered by various researchers in recent years. Microsilica (Silica fume) can also be considered as one of the most widely used additives (admixtures) in this section. In this study, 120 concrete specimens were constructed using a mix design based on ACI in the laboratory with an overview of records and advantages of using microsilica in concrete. The microsilica used in concrete specimens has been considered 2%, 5.5% and 7.5% by weight of cement. Finally impact permeability, tension and uniaxial compressive strength tests were done on concrete specimens and their mechanical properties were evaluated. The results show that microsilica improves the mechanical properties of concrete. The results also show that the use of microsilica in ordinary concrete has a very positive effect in controlling the surface cracks and increasing some strength parameters such as tensile and compressive strength of concrete.


2019 ◽  
Vol 2 (1) ◽  
pp. 61-66
Author(s):  
Abdul Gaus ◽  
Imran Imran ◽  
Chairul Anwar ◽  
Liska Novianti

The Pumice sand is a bright colored butian type, containing foam made from glass-walled bubbles and usually referred to as silicate volcanic glass granules. This pumice sand can be used as a substitute for normal sand as fine aggregate in a mixture of concrete mix. Based on the characteristic test examination, it can be seen that in testing the characteristics of pumice sand to the specifications of normal sand in specific gravity testing and weight testing of quicksand obtained results that are smaller than the specifications of normal sand and absorption tests obtained results greater than specifications on normal sand. The results of the normal sand compressive strength at BN is 250.95 kg /cm2 while the results of the floating sand concrete compressive strength on BPA is 224, 965 kg /cm2. Based on the research it can be concluded that with the same quality of concrete, the quality of K-250 is different in comparison to the compressive strength of concrete in normal sand and pumice sand concrete shows almost the same results. Therefore, more in-depth research is needed regarding the use of pumice sand instead of normal sand in a mixture of concrete mix


2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Abdul Gaus ◽  
Imran Imran ◽  
Liska Novianti

Pumice sand is a bright colored butian type, containing foam made from glass-walled bubbles andusually referred to as silicate volcanic glass granules. This pumice sand can be used as a substitutefor normal sand as fine aggregate in a mixture of concrete mix. Based on the characteristic testexamination, it can be seen that in testing the characteristics of pumice sand to the specificationsof normal sand in specific gravity testing and weight testing of quicksand obtained results thatare smaller than the specifications of normal sand and absorption tests obtained results greaterthan specifications on normal sand. The results of the normal sand compressive strength at BN is250.95 kg /cm2 while the results of the floating sand concrete compressive strength on BPA is224, 965 kg /cm2. Based on the research it can be concluded that with the same quality of concrete,the quality of K-250 is different in comparison to the compressive strength of concrete in normalsand and pumice sand concrete shows almost the same results. Therefore, more in-depth researchis needed regarding the use of pumice sand instead of normal sand in a mixture of concrete mix.


2018 ◽  
Vol 7 (1) ◽  
pp. 19-26
Author(s):  
Rida Respati

In this research, we want to experiment to find out the compressive strength of medium quality concrete K-350 with ingredients added MASTER RHEOBUILD 6, whose function is to accelerate hardening, improve the quality of concrete, reduce water use and increase the value of slump. However, it should be noted that errors in dosages and how to use added ingredients can be detrimental to the quality of concrete. The results of the study show that the addition of 0.25, 0.5 and 0.75 liters per 50 kg of cement can increase the concrete compressive strength. The compressive strength of concrete with the addition of 0.25 liters/50 kg of cement has increased 362.67 kg/cm� from the normal concrete compressive strength of 350.58 kg/cm2. The addition of 0.5 liters/50 kg of cement has increased again to 373.24 kg/cm�, and the addition of 0.75 liters/50 kg of cement has increased the concrete compressive strength to 379.29 kg/cm� of normal concrete. Comparison of compressive strength before and after addition of admixture with an increase of 3.45% in addition of 0.25 liters/50 kg of cement, 6.47% in addition of 0.5 liters/50 kg of cement and 8.19% in addition of 0.75 liters/50 kg of cement.


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.


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