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

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.

2021 ◽  
Vol 11 (9) ◽  
pp. 3866
Author(s):  
Jun-Ryeol Park ◽  
Hye-Jin Lee ◽  
Keun-Hyeok Yang ◽  
Jung-Keun Kook ◽  
Sanghee Kim

This study aims to predict the compressive strength of concrete using a machine-learning algorithm with linear regression analysis and to evaluate its accuracy. The open-source software library TensorFlow was used to develop the machine-learning algorithm. In the machine-earning algorithm, a total of seven variables were set: water, cement, fly ash, blast furnace slag, sand, coarse aggregate, and coarse aggregate size. A total of 4297 concrete mixtures with measured compressive strengths were employed to train and testing the machine-learning algorithm. Of these, 70% were used for training, and 30% were utilized for verification. For verification, the research was conducted by classifying the mixtures into three cases: the case where the machine-learning algorithm was trained using all the data (Case-1), the case where the machine-learning algorithm was trained while maintaining the same number of training dataset for each strength range (Case-2), and the case where the machine-learning algorithm was trained after making the subcase of each strength range (Case-3). The results indicated that the error percentages of Case-1 and Case-2 did not differ significantly. The error percentage of Case-3 was far smaller than those of Case-1 and Case-2. Therefore, it was concluded that the range of training dataset of the concrete compressive strength is as important as the amount of training dataset for accurately predicting the concrete compressive strength using the machine-learning algorithm.


2017 ◽  
Vol 36 (3) ◽  
pp. 734-739
Author(s):  
F Falade ◽  
B Ukponu ◽  
OJ Ugbaja

This paper presents the results of the study on the influence of superplasticizer and varying aggregate size on the drying shrinkage and compressive strength of laterised concrete. Four different samples of laterised concrete were made from prescribed mix ratio of 1:1:2 which include; two control specimens made with different coarse aggregate sizes (12.5mm and 19mm) and another two specimens that have the same composition as the control samples with addition of superplasticizer (Conplast 430). The compressive strength and drying shrinkage were determined at the curing periods (7, 14, 21 and 28 days). The results showed that specimens made with 12.5mm diameter coarse aggregate and superplasticizer developed a maximum compressive strength (44N/mm2) at 28th day. This maximum compressive strength was 29.6%, 31.8% and 4.6% greater than the compressive strength developed by the control specimens and specimens made with 19mm diameter coarse aggregate and superplasticizer. Specimens made with 19mm diameter coarse aggregate and superplasticizer developed the minimum shrinkage strain (1.48⨯0-3) at 90th day. This value was 17%, 13.5% and 8.1% less than shrinkage strain of the control specimens and specimen made with 12.5mm coarse aggregate size and superplasticizer. The addition of superplasticizer increased the compressive strength and reduced the shrinkage strain of all specimens; while increase in coarse aggregate size reduced both compressive strength and drying shrinkage.  http://dx.doi.org/10.4314/njt.v36i3.11


2012 ◽  
Vol 2290 (1) ◽  
pp. 105-114 ◽  
Author(s):  
Liam Butler ◽  
Jeffrey S. West ◽  
Susan L. Tighe

This study focuses on characterizing several recycled concrete aggregate (RCA) sources, developing concrete mixture proportions that incorporate RCA as coarse aggregate, and investigating the effect of coarse aggregate properties on the main mixture proportion parameters [i.e., cement content, water demand, and water–cement (w/c) ratio]. Four aggregate types were investigated: one control virgin aggregate source and three RCAs produced from the crushing of hardened concrete. Numerous aggregate tests, including density, absorption, abrasion resistance, adhered mortar content, and crushing value, were performed. Fourteen mixture proportions were developed with the use of three mixture proportion scenarios (control, direct replacement, and strength based) and two compressive strength levels (40 and 60 MPa). The effect of RCA on compressive strength and workability was evaluated by replacement of natural coarse aggregate with RCA. Contrary to numerous studies, one of the RCA concretes (RCA-1) had compressive strengths up to 12% higher than the equivalent control mixture. Mixture proportions (water, cement, and w/c ratio) were later adjusted to ensure that the RCA concretes had compressive strength and slump values similar to the control concretes. Variations in water demand, cement content, and w/c ratio could then be directly attributed to the properties of the RCA source. RCA-1 concrete required less cement (and a higher w/c ratio) to achieve strengths and slumps similar to the control concrete. The findings and recommendations of this research will assist concrete producers, engineers, and field technicians involved in the selection of RCA sources in developing mixture proportions for structural-grade RCA concrete.


2012 ◽  
Vol 238 ◽  
pp. 133-137 ◽  
Author(s):  
Wei Xie ◽  
Ya Nan Jin ◽  
Shu Shan Li

To discuss the influence of coarse aggregate size, water cement ratio and ages on the concrete compressive strength,the compressive strength tests were carried out by 54 cubic specimens of pebbles concrete in dimensions of 150mm, 18 cubic specimens with dimensions of 200mm and 72 specimens with size of 150mm×150mm×300mm. The results show that the maximum size of coarse aggregate rises with the decrease of the concrete compressive strength; Concrete compressive strength of coarse aggregate size affects more apparently as the ratio of water-cement decrease; with the increasing of age, concrete compressive strength of the aggregate size effect has no significant changes.


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.


Author(s):  
Ahmad Salah Edeen Nassef ◽  
Kalifa Hamed AlMuqbali ◽  
Sheikha Mahmood Al Naqabi

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.


2018 ◽  
Author(s):  
Erniati Bachtiar

Concrete construction technology is directed to be sustainable and ecofriendly. The waste of the candlenut shell as a substitute for the coarse aggregate of concrete mixture is known that the candlenut shell has a hard texture so it may be used as a substitute for coarse aggregates in concrete. The purpose of the research was to determine the effect of Candlenut shell as a substitute of coarse aggregate on physical properties (slump test, bleeding, segregation, volume weight) and mechanical properties (compressive strength and tensile strength) of concrete using Candlenut shell as replacement material of the coarse aggregate. The variation of the research was percentage of the Candlenut shell in the concrete mixture, that was 0%, 25%, 50%, 75% and 100% to the coarse aggregate volume in the concrete mixture. Number of specimens in reseach was each 5 pieces each variation. Testing of mechanical properties of concrete (compressive strength and tensile strength) was performed at 28 days. Testing of the concrete for compressive strength test and tensile strength on age 28 days. Concrete using candlenut shell as a substitute of coarse aggregates has decreased compressive strength respectively 11.72 MPa (37.71%) for 25% candlenut shell; 15.54 MPa (50.00%) for 50% candlenut shell; 18.35 MPa (59.02%) for 75% candlenut shell; And 18,85 MPa (60,66%) for 100% candlenut shell from of the 0% candlenut shell with compressive strength of 31.08 Mpa. Concrete using for 25% candlenut shell as a substitute for coarse aggregates decreased tensile strength respectively of 0.95 MPa (28.70%) for 25% candlenut shell; 1.21 MPa (36.56%) for 50% candlenut shell; 1.27 MPa (38.37%) for 75% candlenut shell; And 1.40 MPa (42.30%) for 100% candlenut shell from of the 0% candlenut shell with the tensile strength of BN of 3.31 MPa. The decrease in the value of compressive strength and tensile strength is strongly influenced by the increasing percentage of Candlenut shells on concrete


2012 ◽  
Vol 2 (1) ◽  
pp. 21-28
Author(s):  
R. G. Solís ◽  
E. Moreno ◽  
E. Arjona

RESUMENLa resistencia del concreto depende de la calidad de la pasta de cemento y de las características de los agregados pétreos. La primera es controlada por la relación agua - cemento, mientras que las propiedades de los agregados generalmente no pueden ser manipuladas ya que se suele utilizar aquellos que están disponibles cerca de la construcción. En muchas regiones rocas con propiedades no deseables son utilizadas como agregado. Por lo tanto, el objetivo de este trabajo fue responder a la pregunta sobre cuál sería la máxima resistencia de diseño que se podría utilizar para concretos fabricados con un tipo específico de agregados obtenidos a partir de la trituración de roca caliza de alta absorción. Se probaron concretos con seis relaciones agua - cemento y dos tamaños de agregado grueso. Se concluyó que con los agregados estudiados es posible fabricar concretos de hasta 500 k/cm2 de f’c.Palabras clave: Absorción; agregados calizos; concreto; relación agua/cemento; resistencia.ABSTRACTConcrete strength depends on the cement paste quality and on the characteristics of the aggregates. The former is controlled by the water to cement ratio, while the properties of the aggregate, in general, cannot be manipulated as it is customary to employ the ones available near the construction site. In many regions rocks with no desirable properties are employed as aggregates. Therefore, the aim of this study was to answer the question about what would that be the maximum compressive strength attainable in concrete made with a specific type of aggregate obtained from crushed limestone of high absorption. Concrete mixtures involved six water to cement ratios and two sizes of coarse aggregate. It was concluded that with this type of aggregate it is possible to made concrete with compressive strength up to 500 k/cm2 of f’c.Key words: Absorption; compressive strength; concrete; limestone aggregate; water/cement ratio.


2021 ◽  
Vol 1 (1) ◽  
pp. 1
Author(s):  
Agung Prayogi

Abstract Concrete is the most widely used material throughout the world and innovations continue to be carried out to produce efficient development. Shell charcoal ash and rice husk ash are industrial by-products which have the potential to replace sand for concrete mix, especially in Indragiri Hilir. The research with the title "Effect of Mixture of Rice Husk Ash and Shell Ash Ashes as Substitute for Some Fine Aggregates Against Concrete Compressive Strength" aims to prove the effect of a mixture of shell charcoal ash and husk ash to replace some of the sand to produce maximum compressive strength. Concrete is a mixture of Portland cement, fine aggregate, coarse aggregate, and water. This research uses 5 variations of the mixture to the weight of sand, BSA 0 without a substitute mixture, BSA 1 with a mixture of 5% husk ash and 10% shell charcoal, BSA 2 with a mixture of 5% husk ash and 15% charcoal ash, BSA 3 with a mixture of 5% husk ash and 18% charcoal, BSA 4 with a mixture of 10% husk and 10% charcoal, and BSA 5 with a mixture of 13% husk ash and 10% charcoal ash. SNI method is used for the Job Mix Formula (JMF) mixture in this research. The results of the average compressive strength of concrete at 28 days for JMF of 21.05 MPa, BSA 1 of 23.68 MPa, BSA 2 of 22.23 MPa, BSA 3 of 14.39 MPa, BSA 4 of 13.34 MPa , and BSA 5 of 20.14 MPa. The conclusion drawn from the results of the BSA 1 research with a mixture of 5% husk ash and 15% charcoal ash produced the highest average compressive strength of 23.68 MPa. Abstrak Beton merupakan material paling banyak digunakan diseluruh dunia dan terus dilakukan inovasi untuk menghasilkan pembangunan yang efisien. Abu arang tempurung dan abu sekam padi merupakan hasil sampingan industri yang berpotensi sebagai pengganti pasir untuk campuran beton, khususnya di Indragiri Hilir. Penelitian dengan judul “Pengaruh Campuran Abu Sekam Padi dan Abu Arang Tempurung Sebagai Pengganti Sebagian Agregat Halus Terhadap Kuat Tekan Beton” ini bertujuan membuktikan adanya pengaruh campuran abu arang tempurung dan abu sekam untuk mengganti sebagian pasir hingga menghasilkan kuat tekan maksimum. Beton adalah campuran antara semen portland, agregat halus, agregat kasar, dan air. Penelitian ini menggunakan 5 variasi campuran terhadap berat pasir, BSA 0 tanpa campuran pengganti, BSA 1 dengan campuran 5 % abu sekam dan 10% arang tempurung, BSA 2 dengan campuran 5% abu sekam dan 15% abu arang, BSA 3 dengan campuran 5% abu sekam dan 18% arang, BSA 4 dengan campuran 10% sekam dan 10% arang, dan BSA 5 dengan campuran 13% abu sekam dan 10% abu arang. Metode SNI digunakan untuk campuran Job Mix Formula (JMF)  pada penelitian ini. Hasil rata-rata kuat tekan beton pada umur 28 hari untuk JMF sebesar 21,05 MPa, BSA 1 sebesar 23,68 MPa, BSA 2 sebesar 22,23 MPa, BSA 3 sebesar 14,39 MPa, BSA 4 sebesar 13,34 MPa, dan BSA 5 Sebesar 20,14 MPa. Ditarik kesimpulan dari hasil penelitian BSA 1 dengan campuran 5% abu sekam dan 15% abu arang menghasilkan rata-rata kuat tekan tertinggi yaitu sebesar 23,68 MPa.  


Author(s):  
Suhaib Bakshi

Abstract: Compressive strength of concrete is the capacity of concrete to bear loads of materials or structure sans breaking or being deformed. Specimen under compression shrinks in size whilst under tension the size elongates. Compressive strength essentially gives concept about the properties of concrete. Compressive strength relies on many aspects such as water-cement ratio, strength of cement, calidad of concrete material. Specimens are tested by compression testing machine after the span of 7 or 28 days of curing. Compressive strength of the concrete is designated by the load on the area of specimen. In this research various proportions of such aggregate mixed in preparing M 30 grade and M 40 grade of Concrete mix and the effect is studied on its compressive strength . Several research papers have been assessed to analyze the compressive strength of concrete and the effect of different zones of sand on compressive strength are discussed in this paper. Keywords: Sand, Gradation, Coarse aggregate, Compressive strength


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