131.
Han Ay Lie; Purwanto
Proceeding : 1st Annual Conference on Architecture and Civil Engineering, 2013, pp. 88-93, vol. 1, 2011.
@proceedings{17,
title = {The Effect of the Interfacial Transition Zone between Aggregate and Mortar to the Overall Performance of Concrete Structures, a comparative study, from micro to macro},
author = {Han Ay Lie and Purwanto},
url = {https://dl4.globalstf.org/?wpsc-product=the-effect-of-the-interfacial-transition-zone-between-aggregate-and-mortar-to-the-overall-performance-of-a-concrete-structure-a-comparative-study-from-micro-to-macro
https://www.researchgate.net/publication/260661635_The_Effect_of_the_Interfacial_Transition_Zone_between_Aggregate_and_Mortar_to_the_Overall_Performance_of_Concrete_Structures_a_comparative_study_from_micro_to_macro},
year = {2011},
date = {2011-08-01},
urldate = {2011-08-01},
journal = {The Effect of the Interfacial Transition Zone between Aggregate and Mortar to the Overall Performance of Concrete Structures, a comparative study, from micro to macro},
volume = {1},
publisher = {Proceeding : 1st Annual Conference on Architecture and Civil Engineering, 2013, pp. 88-93},
series = {Designing and Constructing in Sustainability},
abstract = {The Interfacial Transition Zone (ITZ) between the aggregate and the mortar in concrete has long been recognized as the "weak link" in the material. Research in this field conducted at the Material Laboratory, Diponegoro University resulted in the normal-tensile and shear behavior of the ITZ, based on newly developed test methods. The load-displacement response of the ITZ in their normal and shear mode was lucidly explained. At further stages, a Finite Element Model (FEM) was developed modeling concrete as a three-phase, rather than a two-phase material by including the ITZ into the model. The results of this integrated method showed that the ultimate stress as well as the stiffness modulus of concrete is strongly influenced by the ITZ. In this paper a numerical analysis to the effect of these deviations to a multi-storey structure, is studied. The results demonstrated that the ITZ influences the structure's performance significantly. Techniques to improving the ITZ in concrete can therefore have a positive impact on the overall structural behavior.
Keywords: component; ITZ; Finite Element; Stiffness Modulus; Load-displacement response},
keywords = {},
pubstate = {published},
tppubtype = {proceedings}
}
The Interfacial Transition Zone (ITZ) between the aggregate and the mortar in concrete has long been recognized as the "weak link" in the material. Research in this field conducted at the Material Laboratory, Diponegoro University resulted in the normal-tensile and shear behavior of the ITZ, based on newly developed test methods. The load-displacement response of the ITZ in their normal and shear mode was lucidly explained. At further stages, a Finite Element Model (FEM) was developed modeling concrete as a three-phase, rather than a two-phase material by including the ITZ into the model. The results of this integrated method showed that the ultimate stress as well as the stiffness modulus of concrete is strongly influenced by the ITZ. In this paper a numerical analysis to the effect of these deviations to a multi-storey structure, is studied. The results demonstrated that the ITZ influences the structure's performance significantly. Techniques to improving the ITZ in concrete can therefore have a positive impact on the overall structural behavior.
Keywords: component; ITZ; Finite Element; Stiffness Modulus; Load-displacement response
Keywords: component; ITZ; Finite Element; Stiffness Modulus; Load-displacement response
132.
Han Ay Lie; Nuroji
35th Conference on OUR WORLD IN CONCRETE & STRUCTURES, 2010, 2010.
@proceedings{25,
title = {The Normal and Shear Modulus Properties of the Interfacial Transition Zone in Concrete; Newly Developed Testing Procedures},
author = {Han Ay Lie and Nuroji},
url = {https://www.researchgate.net/publication/260666968_THE_NORMAL_AND_SHEAR_MODULUS_PROPERTIES_OF_THE_INTERFACIAL_TRANSITION_ZONE_IN_CONCRETE_NEWLY_DEVELOPED_TESTING_PROCEDURES},
year = {2010},
date = {2010-08-01},
booktitle = {The Normal and Shear Modulus Properties of the Interfacial Transition Zone in Concrete; Newly Developed Testing Procedures},
publisher = {35th Conference on OUR WORLD IN CONCRETE & STRUCTURES, 2010},
abstract = {The transition zone of the aggregate surface adjacent to the mortar has a distinctive formation, in terms of its mechanical as well as its physical properties. This layer is recognized as the ITZ (Interfacial Transition Zone) and considered the “weak link”, since micro cracks are commonly initiated in this area. The properties of this ITZ only about 50 μm in dimension, are jet to be investigated. SEM (Scanning Electron Microscope) images can only provide qualitative information such as formation, type and relative amount of crystals; therefore other means are required to represent a better understanding to the behavior of the ITZ. The mechanical and physical properties of the ITZ are highly influenced by the differentiation in porosity and strength, as compared to the mortar matrix away from the ITZ. The modulus properties of the ITZ are investigated through newly developed laboratory testing techniques, resulting in load-to-area-displacement curves that can further be incorporated into mathematical or Finite Element Models. The normal and shear properties are tested by individual techniques, both resulting in the load-to-area versus displacement relationship of the ITZ. Further, this experimental study will evaluate the effect of bleeding and aggregate surface roughness to the ITZ’ normal and shear behavior. Two types of aggregates are studied; natural aggregates and steel-slag which is a residue of the steel industry and at present considered as a polluting waste. However, these testing techniques can be expanded to investigate the stiffness behavior of all cement based ITZ aggregates.
Keywords: interfacial transition zone, mortar matrix, aggregate, shear and normal modulus},
keywords = {},
pubstate = {published},
tppubtype = {proceedings}
}
The transition zone of the aggregate surface adjacent to the mortar has a distinctive formation, in terms of its mechanical as well as its physical properties. This layer is recognized as the ITZ (Interfacial Transition Zone) and considered the “weak link”, since micro cracks are commonly initiated in this area. The properties of this ITZ only about 50 μm in dimension, are jet to be investigated. SEM (Scanning Electron Microscope) images can only provide qualitative information such as formation, type and relative amount of crystals; therefore other means are required to represent a better understanding to the behavior of the ITZ. The mechanical and physical properties of the ITZ are highly influenced by the differentiation in porosity and strength, as compared to the mortar matrix away from the ITZ. The modulus properties of the ITZ are investigated through newly developed laboratory testing techniques, resulting in load-to-area-displacement curves that can further be incorporated into mathematical or Finite Element Models. The normal and shear properties are tested by individual techniques, both resulting in the load-to-area versus displacement relationship of the ITZ. Further, this experimental study will evaluate the effect of bleeding and aggregate surface roughness to the ITZ’ normal and shear behavior. Two types of aggregates are studied; natural aggregates and steel-slag which is a residue of the steel industry and at present considered as a polluting waste. However, these testing techniques can be expanded to investigate the stiffness behavior of all cement based ITZ aggregates.
Keywords: interfacial transition zone, mortar matrix, aggregate, shear and normal modulus
Keywords: interfacial transition zone, mortar matrix, aggregate, shear and normal modulus
133.
Han Ay Lie; Nuroji
Laboratory Testing and Modeling the Interfacial Transition Zone of Slag-Concrete Journal Article
In: Media Komunikasi Teknik Sipil, vol. 17, no. 3, pp. 209-223, 2009, ISSN: 2549-6778 (Online) 0854-1809 ( Print).
@article{99,
title = { Laboratory Testing and Modeling the Interfacial Transition Zone of Slag-Concrete},
author = {Han Ay Lie and Nuroji},
url = {https://ejournal.undip.ac.id/index.php/mkts/article/view/5171},
issn = {2549-6778 (Online) 0854-1809 ( Print)},
year = {2009},
date = {2009-05-04},
urldate = {2009-05-04},
journal = {Media Komunikasi Teknik Sipil},
volume = {17},
number = {3},
pages = {209-223},
abstract = {The transition zone at the aggregate surface has a distinctive formation, in terms of its mechanical as well as its physical properties. This layer is recognized as the ITZ (Interfacial Transition Zone) and considered the “weak link”, since micro cracks are commonly initiated in this area. The properties of this ITZ are jet to be investigated. SEM (Scanning Electron Microscope) images only provide qualitative information such as formation, type and relative amount of crystals. Therefore, other means are required to represent a better understanding to the behavior of the ITZ. The mechanical and physical properties of the ITZ are highly influenced by the differentiation in porosity and strength. A mathematical or FEM (Finite Element Model) can be used to bridge this lack of information. This paper deals with the the modeling approach of ITZ as well as the concept of laboratory testing for validation of the model.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The transition zone at the aggregate surface has a distinctive formation, in terms of its mechanical as well as its physical properties. This layer is recognized as the ITZ (Interfacial Transition Zone) and considered the “weak link”, since micro cracks are commonly initiated in this area. The properties of this ITZ are jet to be investigated. SEM (Scanning Electron Microscope) images only provide qualitative information such as formation, type and relative amount of crystals. Therefore, other means are required to represent a better understanding to the behavior of the ITZ. The mechanical and physical properties of the ITZ are highly influenced by the differentiation in porosity and strength. A mathematical or FEM (Finite Element Model) can be used to bridge this lack of information. This paper deals with the the modeling approach of ITZ as well as the concept of laboratory testing for validation of the model.
134.
Sri Tudjono; Han Ay Lie
Proceeding of the Fifth International Conference on Advances in Steel Structures (ICASS) 2007, 2007.
@proceedings{26b,
title = {The Influence of Bearing Stiffeners to Double – Symmetrical I-Section’s Torsion Stiffness, an Analytical Approach},
author = {Sri Tudjono and Han Ay Lie},
url = {http://rpsonline.com.sg/proceedings/icass07/volume3/html/v3-rp0043.xml},
year = {2007},
date = {2007-12-05},
publisher = {Proceeding of the Fifth International Conference on Advances in Steel Structures (ICASS) 2007},
abstract = {Bearing Stiffeners are preventing web-local-buckling and reinforcing this section for point-loads and shear-forces. This paper discusses bearing stiffeners’ contribution in enhancing double-symmetric I-sections’ torsion capacity. Based on the Saint Venant’s formula torsion stresses are carried solemnly by the section, neglecting the stiffeners’ contribution. However, these stiffeners exhibit significant rotational deformation with the I-section in warping, indicating development of internal forces, restraining the warping. Therefore, the negligence of stiffeners’ contribution in Saint Venant’s torsion formula has to be revised.
Torsions within the stiffeners are the Saint Venant’s and torsion-shear-stresses induced by bending. Assuming out-of-plane stresses neglected, normal and bending-shear torsion stresses are zero, leaving only the Saint Venant’s. From equilibrium at the stiffener-to-flange’s-joint, the stiffeners’ natural boundary conditions equation can be obtained. Their presence leads to a rotational-torsion function differentiation along the beam, between stiffeners. But since all points have identical internal torsion forces, the disturbed differential torsion warping equations are identical. Using the geometrical and natural boundary conditions equation the mathematical-rotational-torsion-solution for each field along the beam is obtained.
It can be concluded that the member’s torsion stiffness increases approaching to linear while the increment will approach a hyperbola as a function of stiffeners’ number and thickness, respectively.},
keywords = {},
pubstate = {published},
tppubtype = {proceedings}
}
Bearing Stiffeners are preventing web-local-buckling and reinforcing this section for point-loads and shear-forces. This paper discusses bearing stiffeners’ contribution in enhancing double-symmetric I-sections’ torsion capacity. Based on the Saint Venant’s formula torsion stresses are carried solemnly by the section, neglecting the stiffeners’ contribution. However, these stiffeners exhibit significant rotational deformation with the I-section in warping, indicating development of internal forces, restraining the warping. Therefore, the negligence of stiffeners’ contribution in Saint Venant’s torsion formula has to be revised.
Torsions within the stiffeners are the Saint Venant’s and torsion-shear-stresses induced by bending. Assuming out-of-plane stresses neglected, normal and bending-shear torsion stresses are zero, leaving only the Saint Venant’s. From equilibrium at the stiffener-to-flange’s-joint, the stiffeners’ natural boundary conditions equation can be obtained. Their presence leads to a rotational-torsion function differentiation along the beam, between stiffeners. But since all points have identical internal torsion forces, the disturbed differential torsion warping equations are identical. Using the geometrical and natural boundary conditions equation the mathematical-rotational-torsion-solution for each field along the beam is obtained.
It can be concluded that the member’s torsion stiffness increases approaching to linear while the increment will approach a hyperbola as a function of stiffeners’ number and thickness, respectively.
Torsions within the stiffeners are the Saint Venant’s and torsion-shear-stresses induced by bending. Assuming out-of-plane stresses neglected, normal and bending-shear torsion stresses are zero, leaving only the Saint Venant’s. From equilibrium at the stiffener-to-flange’s-joint, the stiffeners’ natural boundary conditions equation can be obtained. Their presence leads to a rotational-torsion function differentiation along the beam, between stiffeners. But since all points have identical internal torsion forces, the disturbed differential torsion warping equations are identical. Using the geometrical and natural boundary conditions equation the mathematical-rotational-torsion-solution for each field along the beam is obtained.
It can be concluded that the member’s torsion stiffness increases approaching to linear while the increment will approach a hyperbola as a function of stiffeners’ number and thickness, respectively.
135.
Purwanto Purwanto; Bobby Rio Indriyantho; Nuroji Nuroji; Januarti J. Ekaputri; Rydell Riko; Buntara Sthenly Gan; Han Ay Lie
Mix Design Formulation and Stress-Strain Relationship of Fly Ash-Based Workable Geopolymer Concrete: an Experimental Study Journal Article
In: International Review of Civil Engineering (IRECE), vol. 13, no. 4, 0000.
@article{nokey,
title = {Mix Design Formulation and Stress-Strain Relationship of Fly Ash-Based Workable Geopolymer Concrete: an Experimental Study},
author = {Purwanto Purwanto and Bobby Rio Indriyantho and Nuroji Nuroji and Januarti J. Ekaputri and Rydell Riko and Buntara Sthenly Gan and Han Ay Lie},
url = {https://www.praiseworthyprize.org/jsm/index.php?journal=irece&page=article&op=view&path[]=26289},
doi = {https://doi.org/10.15866/irece.v13i4.21515},
journal = {International Review of Civil Engineering (IRECE)},
volume = {13},
number = {4},
abstract = {Geopolymer concrete is known as a concrete made by one of cementitious materials in order to reduce carbon dioxide (CO2) emissions for sustainable development purposes. Instead of using Portland cement for a mortar matrix, mineral residues as a result of power plant processes so-called fly ash are used to replace completely the existence of cement in a concrete structure. A large amount of chemical compounds such as silicon dioxide or silica (SiO2), aluminum oxide (Al2O3) and iron(III) oxide or ferric oxide (Fe2O3) contained in fly ash can substitute Portland cement as a chemical binder in concrete materials. Fly ash Class F which contains more than 70% of SiO2, Al2O3 and Fe2O3 in total with less than 10% of calcium oxide (CaO) has been investigated yielding compressive strengths similar to or even higher than the conventional concrete using Portland cement. In order to obtain a strong chemical binder between aggregates and fly ash, an activator containing a mixture of sodium hydroxide (NaOH) and sodium metasilicate (Na2SiO3) is applied here, where two types of Na2SiO3 (Be52 and Be58) are employed. Further, workability is investigated by comparing Na2SiO3 type Be52 and Na2SiO3 type Be58, with maintaining an acceptable compressive strength. Then the results of proportional mix design variations for geopolymer concrete are analyzed in terms of the modulus of elasticity and the Poisson’s ratio as well as its stress-strain relationship compared to the conventional concrete. },
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Geopolymer concrete is known as a concrete made by one of cementitious materials in order to reduce carbon dioxide (CO2) emissions for sustainable development purposes. Instead of using Portland cement for a mortar matrix, mineral residues as a result of power plant processes so-called fly ash are used to replace completely the existence of cement in a concrete structure. A large amount of chemical compounds such as silicon dioxide or silica (SiO2), aluminum oxide (Al2O3) and iron(III) oxide or ferric oxide (Fe2O3) contained in fly ash can substitute Portland cement as a chemical binder in concrete materials. Fly ash Class F which contains more than 70% of SiO2, Al2O3 and Fe2O3 in total with less than 10% of calcium oxide (CaO) has been investigated yielding compressive strengths similar to or even higher than the conventional concrete using Portland cement. In order to obtain a strong chemical binder between aggregates and fly ash, an activator containing a mixture of sodium hydroxide (NaOH) and sodium metasilicate (Na2SiO3) is applied here, where two types of Na2SiO3 (Be52 and Be58) are employed. Further, workability is investigated by comparing Na2SiO3 type Be52 and Na2SiO3 type Be58, with maintaining an acceptable compressive strength. Then the results of proportional mix design variations for geopolymer concrete are analyzed in terms of the modulus of elasticity and the Poisson’s ratio as well as its stress-strain relationship compared to the conventional concrete.