Experimental Study on Size Effect in Strength of Pervious Concrete and its Associated Factor

2013 ◽  
Vol 634-638 ◽  
pp. 2684-2692 ◽  
Author(s):  
Xi Xi He ◽  
Shan Wu

Based on the test results of compressive strength and splitting strength of three kinds of cubic specimens of pervious concrete whose side length is respectively 100mm, 150mm and 200 mm, the size effect on strength and its associated impact factors which include porosity and particle size of coarse aggregate analyzed. In the test, water cement ratio of every group of concrete mix proportion is constant. The main results are as follows: (1) Size effect on concrete of the pervious concrete is greater than that of ordinary concrete; (2) Size effect on splitting strength is greater than that on cubic compressive strength. (3) Size effect on splitting strength significantly increases with the increase of the aggregate size; (4) Weibull modulus m obtained in statistical test for compressive strength equals to 9, which should be more than twice the value of tensile strength. (5)Size effect on strength of concrete is related to its statistical discreteness, that is, the size effect is more obvious when the dispersion coefficient Cv is greater; (6)Weibull’s statistical size effect can be used to describe the size effect on strength indicators of concrete; Theoretical values of Weibull’s statistical size effect derived from the experiment agree with the test results well. (7) The abnormal trends of size effect are related to the abnormal changes of dispersion coefficient.

2019 ◽  
Vol 276 ◽  
pp. 01025
Author(s):  
Tri Mulyono ◽  
Anisah

The benefit of pervious concrete lies in its ability to transport a large volume of water through its pores to the underlying strata, and it often serves as a pavement for vehicles and pedestrians. This research aimed to determine the properties of pervious concrete based on trials in the laboratory. The method used in this research was a laboratory experiment in accordance with the appropriate standards. The local material used in the mixture was a material composition with Portland Cement Composite with a water-cement (W/C) ratio 0.27 to 0.34, with aggregates of various types and sizes and fly ash and superplasticizer as the added ingredients. The mixture for the trial used 4.25 for the aggregatecement ratio (A/C) with a proportion of 6% for the fine aggregate (sand), 15% flay ash and a low dosage of superplastizer. The test results showed a slight difference in compressive strength and split tensile strength alongside variations in the W/C, including the use of different aggregate types and sizes. The permeability when using natural aggregate was more porous compared to the crushed stone. The effect of the aggregate size from small to large will result in decreased density (unit weight) and increased void in the mixture. Good agreement was reached in the 0.30 wcr mixture with an aggregate size that passed through a 12.5 mm sieve, that was retained at 9.5 mm and that provided suitable compressive strength.


2014 ◽  
Vol 887-888 ◽  
pp. 824-829
Author(s):  
Qing Fang Lv ◽  
Ji Hong Qin ◽  
Ran Zhu

Laminated veneer lumber is taken as an object of study, and use LVL specimens of different sizes for compression test and tensile test. The goal of the experiment is to investigate the size effect on compressive strength and tensile strength as well as the influence of the secondary glued laminated face, which appears in the secondary molding processes. The results show that both compressive strength and tensile strength have the size effect apparently and the existence of the secondary glued laminated face lower the compressive strength of LVL specimens. Afterwards, the relationship between compressive strength and volume along with tensile strength and area are obtained by the test results.


2010 ◽  
Vol 152-153 ◽  
pp. 1176-1179 ◽  
Author(s):  
Feng Lan Li ◽  
Qian Zhu

To improve the application of the new proto-machine-made sand in structural engineering, tests are carried out to study the drying shrinkage of concrete affected by stone powder in proto- machine-made sand. The target cubic compressive strength of concrete is 55 MPa, the main factor varied in mix proportion of concrete is the contents of stone powder by mass of proto-machine-made sand from 3 % to 16 %. The drying shrinkage strains of concrete are measured by the standard method at the ages of 1 d, 3 d, 7 d, 14 d, 28 d, 60 d, 90 d, 120 d, 150 d and 180 d. Based on test results, the drying shrinkage of concrete affected by the contents of stone powder in proto-machine-made sand is analyzed and compared with that of similar test of concrete with traditional machine-made sand, which shows that there is the optimum content of stone powder resulting in the lower drying shrinkage of concrete. The formula for predicting drying shrinkage strain of concrete is proposed.


2018 ◽  
Vol 8 (8) ◽  
pp. 1217 ◽  
Author(s):  
Hanbing Liu ◽  
Guobao Luo ◽  
Haibin Wei ◽  
Han Yu

Pervious concrete (PC), as an environmental friendly material, can be very important in solving urban problems and mitigating the impact of climate change; i.e., flooding, urban heat island phenomena, and groundwater decline. The objective of this research is to evaluate the strength, permeability, and freeze-thaw durability of PC with different aggregate sizes, porosities, and water-binder ratios. The orthogonal experiment method is employed in the study and nine experiments are conducted. The compressive strength, flexural strength, permeability coefficient, porosity, density, and freeze-thaw durability of PC mixtures are tested. Range analysis and variance analysis are carried out to analyze the collected data and estimate the influence of aggregate size, porosity, and water-binder ratio on PC properties. The results indicate that porosity is the most important factor determining the properties of PC. High porosity results in better permeability, but negatively affects the mechanical strength and freeze-thaw durability. PC of 15% porosity can obtain high compressive strength in excess of 20 MPa and favorable freeze-thaw durability of 80 cycles without sacrificing excessive permeability. Aggregate size also has a significant effect on freeze-thaw durability and mechanical strength. Small aggregate size is advantageous for PC properties. PC with 4.75–9.5 mm coarse aggregate presents excellent freeze-thaw durability. The influence of the water-binder ratio on PC properties is not as significant as that of aggregate size and porosity. An optimal mix ratio is required to trade-off between permeability, mechanical strength, and freeze-thaw durability.


2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Teewara Suwan ◽  
Pitiwat Wattanachai

Global warming is a vital issue addressed to every sector worldwide, including the construction industry. To achieve the concept of green technology, many attempts have been carried out to develop low-carbon footprint products. In the construction sector, Autoclaved Aerated Concrete (AAC) has become more popular and been manufactured to meet the construction demand. However, errors from manufacturing process accounted for approximately 3 to 5% of the AAC production. The development of AAC waste as lightweight aggregate in concrete is one of the potential approaches which was extendedly studied in this paper. The results showed that the compressive strength of AAC-LWA concrete was decreased with an increase in volume and coarse size. The optimum mix proportion was the AAC aggregate size of 1/2′′ to 3/8′′ with 20 to 40% replacement to normal weight aggregate. Internal curing by AAC-LWA was also observed and found to provide sufficient water inside the specimens, leading to an achievement in higher compressive strength. The main goal of this study is not only utilising unwanted wastes from industry (recycling of waste materials) but also building up a new knowledge of using AAC-LWA as an internal curing agent as well as the production of value-added lightweight concrete products.


2011 ◽  
Vol 225-226 ◽  
pp. 577-580
Author(s):  
Yong Ye ◽  
Yi Zhou Cai

The objective of this study is to investigate and evaluate the effect of fine aggregates (aggregate size smaller than or equal to 2.36 mm) on the compressive strength and creep behavior of asphalt mixtures. The variables that are considered in the study include the sizes and gradations of fine aggregate. A kind of standant aggregate gradation and four kinds of reduced aggregate gradation mixture specimens are used. Uniaxial compression and static creep tests were realized at different loading conditions. The test results showed that the different fine aggregate sizes do not result in significant differences in compressive strength and creep values using the same percentage of fine aggregates (38.4%). Only the different gradations showed a little differences for mixtures made with different gradations but same aggregate size (between 2.36 and 1.18 mm).


2012 ◽  
Vol 229-231 ◽  
pp. 233-238 ◽  
Author(s):  
Ze Hui Chen ◽  
Chang Wu Liu ◽  
Ji Wei Deng

Using the MTS testing machine, the uniaxial compressive test of varisized da-qing limestones were undertaken, and the effect of dimensions about compressive strength, peak strain, elastic modulus and destructional forms of rock specimens were studied. It demonstrates that along with the increase of length-diameter ratio, peak strain and compressive strength turn smaller, elastic modulus gradually increases, the destruction of rock samples have a transformation from splitting failure to shear failure. Combined with the test results, Obert L model and Yang Shengqi model, the two size-effect models with extensive applications are analyzed and contrasted. And the conclusion is drawn that Obert L model has a relatively broad applicability, while Yang Shengqi model has a stronger Targeting and higher accuracy. Thus based on the Yang Shengqi model, the size-effect model of da-qing limestone is put forward, and the result indicates that this model corresponds well with the test results, having certain practical value.


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.


2019 ◽  
Vol 209 ◽  
pp. 463-475 ◽  
Author(s):  
Fan Yu ◽  
Daquan Sun ◽  
Jue Wang ◽  
Minjun Hu

2021 ◽  
Vol 871 ◽  
pp. 330-339
Author(s):  
Fang Hua Li

Self-compacting steel fiber concrete must meet the strength standard after steel fiber is added and must have good fluidity. The test results show that the addition of steel fiber to concrete will affect the fluidity of concrete. Compared with ordinary concrete, the addition of steel fiber will improve the compressive strength and flexural tensile strength of concrete to varying degrees. The mix proportion test can be carried out in stages, i.e. the mix proportion meeting all performance indexes used is determined first, then steel fiber is added and adjusted to determine the best mix proportion.


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