scholarly journals THE INFLUENCE FACTOR ON THE COMPRESSIVE STRENGTH OF POROUS CONCRETE : The influence of vibration and coarse aggregate size on the binder distribution and compressive strength in porous concrete

Author(s):  
Toshihiro OTANI ◽  
Kiyoshi MURAKAMI ◽  
Yoshiaki SATO ◽  
Yoshiyuki MITSUI ◽  
Takayuki HIRAI
2014 ◽  
Vol 911 ◽  
pp. 433-437 ◽  
Author(s):  
A.H. Nur Hidayah ◽  
Md Nor Hasanan ◽  
P.J. Ramadhansyah

Properties of Porous Concrete Paving Blocks (PCPB) were investigated in this study. Two groups of coarse aggregate sizes were performed; passing 8 mm retains 5 mm and passing 10 mm retains 8 mm. For mixture design, 100 % of coarse aggregate were used. However, fine aggregate was eliminated in this investigation. The density, water absorption, flakiness index and elongation index test were performed to determine the properties of the coarse aggregate used in this study. Compression test and skid resistance test were used to evaluate the performance of PCPB. The results show that PCPB containing coarse aggregate size 5 8 mm give high compressive strength compared to others PCPB specimen. In addition, both PCPB specimens give an in increasing in skid resistance approximately 30 % compared to Concrete Paving Blocks (CPB).


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.


Author(s):  
Samson Olalekan Odeyemi

The need for porous concrete has become increased due its ability to control surface water, increase the rate of recharging groundwater, and reduce pollution of the ecosystem. Granite is a coarse aggregate that is quite expensive when compared with gravel in Nigeria. Therefore, this research is aimed at optimizing blended granite and gravel in the production of porous concrete. Samples of blended granite-gravel porous concrete of varying mix proportions were produced using cement to aggregate mix ratio of 1:4. The samples were tested for their porosity, workability and compressive strengths. The data collected were analyzed with the aid of Design Expert 10.0. It was observed that the optimal combination for the granite-gravel blended porous concrete is 12% granite, 88% gravel, and a water-cement ratio of 0.66%. This combination gave a porous concrete with a compressive strength of 48.4 N/mm2, percentage porosity of 6% and a compacting factor of 0.91. These values when compared to that of the control specimen revealed that the optimal mix gave a porous concrete with higher porosity, higher workability and a better compressive strength.


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.


Author(s):  
Lawrence Echefulechukwu Obi

This work was necessitated by the observations made at construction sites where artisans and craftsmen were left alone in concrete production. It was discovered that they used inadequate quantity and size of coarse aggregates due to difficulty associated in the mixing as if the coarse aggregates were not needed in concrete production. The research has established that the coarse aggregates and their sizes play critical roles in the development of adequate strength in concrete. It was observed that with proper mixing, the slump test results did not witness shear or collapse type of slump rather there were true slump in all cases of the test. The workability decreased with slight differences when the coarse aggregate size was increased. The increase in the coarse aggregates yielded appreciable increase in the compressive strength. It can therefore be inferred that the quality of concrete in terms of strength can be enhanced through an increase in the coarse aggregate size when proper mix ratio, batching, mixing, transporting, placing and finishings are employed in concrete productions.


2021 ◽  
Vol 28 (3) ◽  
pp. 48-60
Author(s):  
Mahdi Mahdi ◽  
Raad Irzooki ◽  
Mazin Abdulrahman

Rainwater harvesting and flood prevention in cities are significant urban hydrological concerns. The use of porous pavement is one of the most effective solutions to handle this matter. Thus, this study aims to develop Porous Interlocking Concrete Pavement (PICP) using recycled aggregate from concrete waste. This porous pavement, then later, can be utilized in low traffic areas and parking lots to harvest water by infiltration and reduce surface runoff. First, the physical properties of the porous concrete blocks, such as density (unit weight), absorption, coefficient of permeability, and porosity, were studied. Also, the mechanical properties of concrete mixtures like compressive strength and flexural strength were tested. This study used two types of PICP, the first one with ordinary coarse aggregate (P1) and the second with recycled crushed concrete coarse aggregate (P2), and then compared their performance to the conventional concrete pavement blocks used the two types of coarse aggregate (R1 and R2). The results show that the unit weight (density) of porous types was reduced by 25% and 26%, and the total porosity increases by around 2.4 times and 18 times respectively, as compared to conventional concrete pavement types. However, the compressive strength and flexural strength of porous concrete types decreased by (55% and 71%), respectively, compared to conventional types. Overall, the infiltration test results showed that the infiltrated water through porous concrete increased by about 83% in comparison to conventional concrete. From the results, utilizing porous concrete pavement can be considered a promising material in terms of water harvesting and decreasing rainwater flooding. Additionally, using recycled concrete can bring economical and environmental benefits.


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


2019 ◽  
Vol 2 (2) ◽  
pp. 72
Author(s):  
Edi Kurniadi ◽  
Lava Himawan

<p><em>No fines concrete can be known such as porous concrete, no-fines concrete and pervious concrete, because not use of sand in the mixture causing the cavities between coarse aggregates. When the rainy season, especially in urban areas there are many flood because the water is difficult to infiltration into the ground. Because permeable nature of non-fines concrete which can accelerate the absorption of water to the soil and to the water channel, reduce run-off and increase groundwater reserves. In this research will study for compressive strength and infiltration in non-finnes concrete. This research uses coarse aggregates from the results of stone crushing machines with coarse aggregate sizes (5-10) mm. cement: aggregate ratio used 1: 2; 1: 3; 1: 4; 1: 5; 1: 6; 1: 7; 1: 8. The study began with material checking, planning of material requirements, making non-sand concrete, then testing compressive strength, and infiltration testing at the age of 28 days. The results showed that the compressive strength of non-finnes concrete with a variation of the ratio of cement : gravel 1: 2  is  33.19 MPa while for a mixture of 1: 8 it is 5.23 MPa. The Infiltration rate has increased along with the greater variation in the ratio of the mixture. The maximum infiltration rate for a mixture of 1: 8 is 9.44 mm/sec. The infiltration rates in no-finnes concrete can be used to accelerate the absorption of water into the soil and can function to reduce water on the surface of the yard.</em></p>


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