• Title/Summary/Keyword: aggregate size

Search Result 588, Processing Time 0.037 seconds

A Study on the Influence of Aggregate on the Estimation of Compressive Strength by Small Size Core (소구경 코어에 의한 콘크리트 압축강도 추정에 미치는 골재의 영향에 관한 연구)

  • 김경민;백병훈;한민철;윤기원;한천구;송성진
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2002.11a
    • /
    • pp.51-54
    • /
    • 2002
  • This study is intended to investigate an influence of the kinds and the maximum size of aggregate on the compressive strength of small size core specimen. According to the results, the compressive strength of standard specimen is large in order of basalt, granite and limestone aggregate, and shows increasing tendency as the maximum size of aggregate grows large. The compressive strength of concrete using basalt aggregate shows similar tendency to granite aggregate, and that of concrete using limestone aggregate decreases slightly, compared with granite aggregate. The reducing ratio of the compressive strength of 25mm core specimen is least when the maximum size of aggregate is 10mm. But the compressive strength of 50 and 100mm core specimen is almost not influenced by the maximum size of aggregate.

  • PDF

Fundamental Properties of Porous Concrete by Aggregate Size

  • Kim, Moo-Han;Kim, Gyu-Yong;Baik, Yong-Kwan;Kim, Jae-Hwan;Cho, Bong-Suk
    • International Journal of Concrete Structures and Materials
    • /
    • v.18 no.2E
    • /
    • pp.117-124
    • /
    • 2006
  • Porous concrete has been used recently for the purpose of decreasing the load on the earth environment. It consists solely of cement, water and coarse aggregate of uni form size. Its fundamental properties are considerably affected by the physical properties of aggregate because the aggregate is the main material for the most part in its mix proportion. Because of this reason, this study carried out an investigation of the influence of the size and type of aggregate on the fundamental properties of porous concrete. It is shown that the fundamental properties of porous concrete was seldom affected by the size of aggregate except for the case of using $2.5{\sim}5mm$ aggregate but varied significantly by the type of aggregate. In particular, the compressive strength of porous concrete using $2.5{\sim}5mm$ aggregate was much higher than that using other aggregate, and its void ratio and coefficient of permeability was lower. Moreover, the capacity to maintain the permeability of porous concrete was found to vary by the size and type of aggregate. Of particular notice was that it decreased greatly when $2.5{\sim}5mm$ aggregate was used. Unlike ordinary concrete, porous concrete exhibited very high dynamic modulus of elasticity at early age and continued to increase but slowly afterwards.

Application of Scaling Theories to Estimate Particle Aggregation in a Colloidal Suspension

  • Park, Soongwan;Koo, Sangkyun
    • Korean Chemical Engineering Research
    • /
    • v.60 no.2
    • /
    • pp.260-266
    • /
    • 2022
  • Average aggregate size in particulate suspensions is estimated with scaling theories based on fractal concept and elasticity of colloidal gel. The scaling theories are used to determine structure parameters of the aggregates, i.e., fractal dimension and power-law exponent for aggregate size reduction with shear stress using scaling behavior of elastic modulus and shear yield stress as a function of particle concentration. The structure parameters are utilized to predict aggregate size which varies with shear stress through rheological modeling. Experimentally rheological measurement is conducted for aqueous suspension of zinc oxide particles with average diameter of 110 nm. The predicted aggregate size is about 1135 nm at 1 s-1 and 739 nm at 1000 s-1 on the average over the particle concentrations. It has been found that the predicted aggregate size near 0.1 s-1 agrees with that the measured one by a dynamic light scattering analyzer operated un-sheared.

Passing Performance of HPC Between Reirforcing Bar with Maximum Size of Coarse Aggregate (굵은골재의 최대치수에 따른 고성능 콘크리트의 간극통과성)

  • Yoon, Seob;Baik, Dae-Hyun;Kim, Jung-Bin;Park, Chang-Soo;Lee, Seong-Yeun;Han, Cheon-Goo
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2006.05b
    • /
    • pp.129-132
    • /
    • 2006
  • This paper is to investigate passing performance of high performance concrete between reinforcing bar depending on maximum size of coarse aggregates. Increase in maximum size of coarse results in decrease in water demand and sand to aggregate to secure target slump flow. The larger the maximum size of coarse aggregates is, the denser the space between reinforcing bar is, the amount of concrete passed through the reinforcing bar cage shows to decrease. HPC has favorable passing performance, regardless of aggregate size, when only vertical reinforcing bar is arranged. Whereas, when vertical and horizontal reinforcing bar is arranged at the same time, proper space between reinforcing bar is considered larger than 32mm in case of using 20mm coarse aggregate, 38mm in case of using 25mm aggregate. The increase in maximum size of coarse aggregate leads to increase compressive strength slightly. Length change shows to be decreased with the increase in maximum size of coarse aggregate.

  • PDF

Development of Aggregate Recognition Algorithm for Analysis of Aggregate Size and Distribution Attributes (골재 크기와 분포 특성을 분석하기 위한 골재 인식 알고리즘 개발)

  • Seo, Myoung Kook;Lee, Ho Yeon
    • Journal of Drive and Control
    • /
    • v.19 no.3
    • /
    • pp.16-22
    • /
    • 2022
  • Crushers are equipment that crush natural stones, to produce aggregates used at construction sites. As the crusher proceeds, the inner liner becomes worn, causing the size of the aggregate produced to gradually increase. The vision sensor-based aggregate analysis system analyzes the size and distribution of aggregates in production, in real time through image analysis. This study developed an algorithm that can segmentate aggregates in images in real time. using image preprocessing technology combining various filters and morphology techniques, and aggregate region characteristics such as convex hull and concave hull. We applied the developed algorithm to fine aggregate, intermediate aggregate, and thick aggregate images to verify their performance.

Effect of Maximum Size of Coarse Aggregate on Passing Performance of Concrete between Reinforcing Bars (굵은골재의 최대치수가 콘크리트의 간극통과성에 미치는 영향)

  • Baik Dae-Hyun;Yoon Seob;Kim Jung-Bin;Lee Seong-Yeun;Yoon Ki-Won;Han Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2006.05a
    • /
    • pp.77-80
    • /
    • 2006
  • This study investigated filling performance of concrete which can pass between reinforcing bars and be fully filled, and examined fundamental properties of concrete which is before or after hardened state, in response to maximum size of coarse aggregate. This study was also originally intended to find out one of the method that can improve concrete quality, using crushed coarse aggregate. Test showed that passing ratio of concrete decreased as aggregate site increased and as space between reinforcing bars decreased. In addition concrete using bigger size of coarse aggregate exhibited slightly higher compressive strength and showed lower length change ratio of drying shrinkage.

  • PDF

Initial Performance Evaluation of Fine-size Exposed Aggregate PCC Pavement by Experimental Construction (시험시공을 통한 소입경 골재노출 콘크리트포장의 초기 공용성 평가)

  • Kim, Young-Kyu;Choi, Don-Hwa;Lee, Seung-Woo;Kim, Hyung-Bae
    • International Journal of Highway Engineering
    • /
    • v.12 no.1
    • /
    • pp.87-98
    • /
    • 2010
  • Surface of fine-size exposed aggregate Portland cement concrete pavements is consists of exposed coarse aggregate by removing upper 2~3mm mortar of concrete slab. Fine-size exposed aggregate PCC pavements have advantages of maintaining low-noise and adequate skid-resistance level during the performance period. In order to provide the successful exposed concrete aggregate pavement, uniform distribution of the coarse aggregate on pavement surface through adequate the mix design and exposing method. In this study, evaluated initial performance of fine-size exposed aggregate PCC pavement by experimental construction. And it was known that fine-size exposed aggregate concrete pavement which can reduce the noise and maintain the adequate level of skid resistance and strength.

An Experimental Study on the Properties of Concrete according to G/S ratio classified by Maximum Size of Coarse Aggregate (굵은골재 최대치수별 굵은골재/잔골재 용적비에 따른 콘크리트의 특성에 관한 실험적 연구)

  • Kim, Duk-Hyun;Lee, Sang-Soo;Song, Ha-Young;Kim, Eul-Yong
    • Journal of the Korea Institute of Building Construction
    • /
    • v.4 no.2
    • /
    • pp.97-103
    • /
    • 2004
  • In this study, the experiment was carried out to investigate and analyze the influence of coarse aggregate's mix ratio and maximum size on the properties of concrete. The main experimental variables were water/cement ratio 45% and 65%, coarse aggregate/fine aggregate ratio 90%, 130% and 170%, maximum size of coarse aggregate 15mm, 25mm and 40mm. According to the test results, the principal conclusions are summarized as follows. 1) The slump and flow of fresh concrete were found to be higher in the order of G/S ratio 170%, 130%, 90%, also in the order of maximum size 40mm, 25mm, 15mm. 2) The compressive strength of hardened concrete were found to be higher in the order of G/S ratio 170%, 130%, 90%, also in the order of maximum size 15mm, 25mm, 40mm.

Long-Term Performance of High Strength Concrete

  • Choi Yeol;Kang Moon-Myung
    • Journal of the Korea Concrete Institute
    • /
    • v.16 no.3 s.81
    • /
    • pp.425-431
    • /
    • 2004
  • This paper describes an experimental investigation of how time-dependent deformations of high strength concretes are affected by maximum size of coarse aggregate, curing time, and relatively low sustained stress level. A set of high strength concrete mixes, mainly containing two different maximum sizes of coarse aggregate, have been used to investigate drying shrinkage and creep strain of high strength concrete for 7 and 28-day moist cured cylinder specimens. Based upon one-year experimental results, drying shrinkage of high strength concrete was significantly affected by the maximum size of coarse aggregate at early age, and become gradually decreased at late age. The larger the maximum size of coarse aggregate in high strength concrete shows the lower the creep strain. The prediction equations for drying shrinkage and creep coefficient were developed on the basis of the experimental results, and compared with existing prediction models.

Effect of Replacement of Recycled Coarse Aggregate with 13mm on Engineering Properties of the Concrete (13mm 크기 순환굵은골재 치환이 콘크리트의 공학적 특성에 미치는 영향)

  • Kang, Byeog-Hoe;Zhao, Yang;Park, Jae Yong;Jo, Man-Ki;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2014.11a
    • /
    • pp.137-138
    • /
    • 2014
  • The aim of this research is suggesting the method of obtaining well-graded aggregates for concrete replacing the recycled aggregate which size range is from 5 to 13 mm to currently used gap-graded natural aggregates which size range is only 13 to 25 mm. according to the tests results, the workability of concrete was improved with replacing the aggregates of 5 to 13 mm of size range because of compensating gap-grading. Furthermore, there was an improvement in compressive strength when the aggregates of 5 to 13 mm of size range was replaced because obtained well-graded aggregates contributed on increasing adhesiveness and filling internal pore system. Comparing replacing recycled aggregate to natural aggregate, there was no significant difference on the performances.

  • PDF