'n Koste vergelykende studie tussen konvensionele ongewapende beton en spanbeton pakhuisvloere wat vir puntlaste ontwerp is
- Authors: Vilonel, Jacobus Philippus
- Date: 2014-11-17
- Subjects: Prestressed concrete construction , Floors, Concrete - Design and construction
- Type: Thesis
- Identifier: uj:12842 , http://hdl.handle.net/10210/12730
- Description: M.Ing. (Civil Engineering) , Please refer to full text to view abstract
- Full Text:
- Authors: Vilonel, Jacobus Philippus
- Date: 2014-11-17
- Subjects: Prestressed concrete construction , Floors, Concrete - Design and construction
- Type: Thesis
- Identifier: uj:12842 , http://hdl.handle.net/10210/12730
- Description: M.Ing. (Civil Engineering) , Please refer to full text to view abstract
- Full Text:
Effect of surface treatments on abrasion and permeation properties of clay concretes
- Solomon, Fitsum, Ekolu, Stephen
- Authors: Solomon, Fitsum , Ekolu, Stephen
- Date: 2014
- Subjects: Reinforced concrete , Concrete construction , Floors, Concrete - Design and construction
- Type: Article
- Identifier: uj:5066 , ISBN 9781614994657 , ISSN 9781614994664 , http://hdl.handle.net/10210/13637
- Description: The resistance of concrete surfaces to various types of wear can be a defining performance characteristic in certain applications. Some concrete structures are required to be abrasion-resistant; among them are dams, canals, roads, floors, footpaths, parking lots, and paths in parks. The work reported in this paper is based on a laboratory study of the concrete-surface treatments (CSTs) consisting of dry shake and screeding. Four control concrete mixtures were prepared with ordinary Portland cement (OPC), having a cement content (CC) of 350 kg/m3 at water-cementitious ratio (w/cc) = 0.70, 0.75; and 280 kg/m3 CC of w/cc = 0.80, 0.85. Other concrete mixtures were then prepared by substituting OPC in the control mixtures with 10, 20, 30, and 40% local raw clay. Compressive strength, abrasion resistance, and air permeability of the surface-treated concretes were measured at the ages of six months, while drying shrinkage was monitored for up to year. Drying shrinkage of concrete reduced with decrease in w/cc ratio and increased with increase in raw clay content. Among all the mixtures, the control concrete of w/cm ratio = 0.70 and the claycement concrete containing w/cm=0.80 at 70% OPC/30% raw clay showed the least and highest shrinkage increments respectively. Abrasion resistance of concrete, measured by the rotating-cutter method, increased with increasing clay content and decreasing compressive strength. However, abrasion performance results of clay-cement concrete mixtures with CSTs were generally higher. Air permeability of the concretes was measured and its relationship with the depth of abrasion of the concrete was examined
- Full Text:
- Authors: Solomon, Fitsum , Ekolu, Stephen
- Date: 2014
- Subjects: Reinforced concrete , Concrete construction , Floors, Concrete - Design and construction
- Type: Article
- Identifier: uj:5066 , ISBN 9781614994657 , ISSN 9781614994664 , http://hdl.handle.net/10210/13637
- Description: The resistance of concrete surfaces to various types of wear can be a defining performance characteristic in certain applications. Some concrete structures are required to be abrasion-resistant; among them are dams, canals, roads, floors, footpaths, parking lots, and paths in parks. The work reported in this paper is based on a laboratory study of the concrete-surface treatments (CSTs) consisting of dry shake and screeding. Four control concrete mixtures were prepared with ordinary Portland cement (OPC), having a cement content (CC) of 350 kg/m3 at water-cementitious ratio (w/cc) = 0.70, 0.75; and 280 kg/m3 CC of w/cc = 0.80, 0.85. Other concrete mixtures were then prepared by substituting OPC in the control mixtures with 10, 20, 30, and 40% local raw clay. Compressive strength, abrasion resistance, and air permeability of the surface-treated concretes were measured at the ages of six months, while drying shrinkage was monitored for up to year. Drying shrinkage of concrete reduced with decrease in w/cc ratio and increased with increase in raw clay content. Among all the mixtures, the control concrete of w/cm ratio = 0.70 and the claycement concrete containing w/cm=0.80 at 70% OPC/30% raw clay showed the least and highest shrinkage increments respectively. Abrasion resistance of concrete, measured by the rotating-cutter method, increased with increasing clay content and decreasing compressive strength. However, abrasion performance results of clay-cement concrete mixtures with CSTs were generally higher. Air permeability of the concretes was measured and its relationship with the depth of abrasion of the concrete was examined
- Full Text:
Identifying the effects of excessive deflection in reinforced concrete beam
- Ogbeifun, E., Pretorius, J. H., Mbohwa, Charles, Ogbeifun, E
- Authors: Ogbeifun, E. , Pretorius, J. H. , Mbohwa, Charles , Ogbeifun, E
- Date: 2014
- Subjects: Reinforced concrete construction , Concrete beams , Floors, Concrete - Design and construction
- Type: Article
- Identifier: uj:5084 , http://hdl.handle.net/10210/13655
- Description: In framed reinforced concrete structure, the beams transfers the dead and live loads to the column and then to the foundation. When there are observed structural failure in the systems supported by the beam, especially where the beam has a large unsupported clear span at a lower level, before any further detailed investigations are initiated, the functional state of the beams should be ascertained. The correct diagnosis of the source of problem is essential for the design of effective rehabilitation scheme. Simple visual inspection corroborated with field test for true horizontality of the beam can provide the lead information that will guide the client on the scope of further investigations. The case study method of qualitative research was adopted to address the research questions, while the research data was collected by reviewing previous investigation reports on a three-storey building, physical inspection and conducting simple site experiment to identify the lead information. The research outcome reveals that the multiple cracks observed in the partition walls especially in the second floors were as a result of excessive deflections in the beams supporting the first and second floors. Based on recommendation, subsequent investigation confirmed this lead information and appropriate rehabilitation scheme was adopted.
- Full Text:
- Authors: Ogbeifun, E. , Pretorius, J. H. , Mbohwa, Charles , Ogbeifun, E
- Date: 2014
- Subjects: Reinforced concrete construction , Concrete beams , Floors, Concrete - Design and construction
- Type: Article
- Identifier: uj:5084 , http://hdl.handle.net/10210/13655
- Description: In framed reinforced concrete structure, the beams transfers the dead and live loads to the column and then to the foundation. When there are observed structural failure in the systems supported by the beam, especially where the beam has a large unsupported clear span at a lower level, before any further detailed investigations are initiated, the functional state of the beams should be ascertained. The correct diagnosis of the source of problem is essential for the design of effective rehabilitation scheme. Simple visual inspection corroborated with field test for true horizontality of the beam can provide the lead information that will guide the client on the scope of further investigations. The case study method of qualitative research was adopted to address the research questions, while the research data was collected by reviewing previous investigation reports on a three-storey building, physical inspection and conducting simple site experiment to identify the lead information. The research outcome reveals that the multiple cracks observed in the partition walls especially in the second floors were as a result of excessive deflections in the beams supporting the first and second floors. Based on recommendation, subsequent investigation confirmed this lead information and appropriate rehabilitation scheme was adopted.
- Full Text:
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