• International Journal of Concrete Structures and Materials
• /
• v.6 no.4
• /
• pp.239-246
• /
• 2012

Pervious concrete is a tailored-property concrete with high water permeability which allow the passage of water to flow through easily through the existing interconnected large pore structure. This paper reports the results of an experimental investigation into the development of pervious concrete with reduced cement content and recycled concrete aggregate for sustainable permeable pavement construction. High fineness ground granulated blast furnace slag was used to replace up to 70 % cement by weight. The properties of the pervious concrete were evaluated by determining the compressive strength at 7 and 28 days, void content and water permeability under falling head. The compressive strength of pervious concrete increased with a reduction in the maximum aggregate size from 20 to 13 mm. The relationship between 28-day compressive strength and porosity for pervious concrete was adversely affected by the use of recycled concrete aggregate instead of natural aggregate. However, the binder materials type, age, aggregate size and test specimen shape had marginal effect on the strength-porosity relationship. The results also showed that the water permeability of pervious concrete is primarily influenced by the porosity and not affected by the use of recycled concrete aggregate in place of natural aggregate. The empirical inter-relationships developed among porosity, compressive strength and water permeability could be used in the mix design of pervious concrete with either natural or recycled concrete aggregates to meet the specification requirements of compressive strength and water permeability.

• Computers and Concrete
• /
• v.20 no.6
• /
• pp.655-661
• /
• 2017

Fiber reinforced concretes exhibit higher tensile strength depending on the percent and type of the fiber used. These concretes are used to reduce cracks and improve concrete behavior. The use of these fibers increases the production costs and reduces the compressive strength to a certain extent. Therefore, the use of fiber reinforced concrete in regions where higher tensile strength is required can cut costs and improve the overall structural strength. The behavior of fiber reinforced concrete and normal concrete adjacent to each other was investigated in the present study. The concrete used was self-compacting and did not require vibration. The samples had 0, 1, 2 and 4 wt% polypropylene fibers. 15 cm sample cubes were subjected to uniaxial loads to investigate their compressive strength. Fiber Self-Compacting Concrete was poured in the mold up to 0, 30, 50, 70 and 100 percent of the mold height, and then Self-Compacting Concrete without fiber was added to the empty section of that mold. In order to investigate concrete behavior under bending moment, concrete beam samples with similar conditions were prepared and subjected to the three-point bending flexural test. The results revealed that normal Self-Compacting Concrete and Fiber Self-Compacting Concrete may be used in adjacent to each other in structures and structural members. Moreover, no separation was observed at the interface of Fiber Self-Compacting Concrete and Self-Compacting Concrete, either in the cubic samples under compression or in the concrete beams under bending moment.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1999.10a
• /
• pp.237-240
• /
• 1999

This study was performed to analyze strength characteristics of concrete using FWS(foundry waste sand), as a way of study for reusing the FWS disused in the foundry as the fine aggregate for concrete. As the experimental results, the slump of concrete showed a decline with the increase of replacement ratio of FWS. The compressive strength of concrete made with FWS 25% replacement river sand showed higher value than that of concrete not containing FWS, but the flexural strength of concrete containing FWS was decreased 21% compared with that of concrete not containing FWS at age of 28days.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2001.11a
• /
• pp.355-362
• /
• 2001

This study deals with cracking control of concrete deck in steel-concrete composite bridges according to the concrete slab casting sequences. In correlation studies between casting sequences, time dependent effects of concrete creep and shrinkage are implemented in the analytical model. Finally, the methods of cracking control in terms of concrete slump and relative humidity are suggested to prevent early transverse cracking of concrete slab.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2000.10a
• /
• pp.241-246
• /
• 2000

In the strut-tie model design of structural concrete, the importance of the effective strength of concrete strut has been overlooked by many practitioners. The authors believe that the effective strength of concrete strut is an important factor not only in determining steel tie forces but also in verifying the nodal zone strength and geometric compatibility condition of a selected strut-tie model. This study evaluate the effect of the effective strength of concrete strut on structural concrete design by applying the different effective strut strengths to the strut-tie model design of a post-tensioned anchorage zone and a continuous concrete deep beam.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1993.10a
• /
• pp.232-236
• /
• 1993

The Tunnel Form(T/F) system instead of traditional euro form has been tried to reduce construction duration and to improve concrete quality in reinforced concrete wall type apartment construction. To find the relationship for concrete compressive strength between cylinder mold and slab, the different curing locations of concrete cylinder mold in the room have been investigated. The test results showed that the compressive strength of the cylinder concrete with middle-upper location in the room was most near concrete compression strength with respect to slab concrete strength.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1997.04a
• /
• pp.649-656
• /
• 1997

The properties of super-flowing concrete with low heat cement were experimentally investigated and compared with ordinary 25-240-15 concrete with type Vcement. The cement content of super-flowing concrete with the low heat cement was 400 kg/$\textrm{m}^3$. However the hydration heat of super-flowing concrete is relatively lower than that ordinary concrete with type V cement. Also the ability to resist chloride ion penetration of super-flowing concrete with low heat cement is 5 times better than that of the ordinary concrete.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2005.05b
• /
• pp.81-84
• /
• 2005

We investigated the effect of inorganic impurities such as clay bricks and asphalt concrete in recycled aggregate on the properties of lean concrete. The optimized moisture content of lean concrete with clay bricks increased, because the absorption ratio of clay bricks is high. On the other hand, lean concrete with asphalt concrete produced an opposite result owing to low absorption ratio. The results showed that inorganic impurities did not have a significant effect on compressive .strength of lean concrete containing below 30$\%$ clay bricks and below 10$\%$ asphalt concrete.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1996.04a
• /
• pp.160-165
• /
• 1996

The tensile of concrete in one of important factor for study of reinforced concrete as well as prestressed concrete structures. In many countries, a numerous experimental studies are being undertaken to investigate correlation between compressive and tensile strength of concrete. This study is focused on identifying the relationship between the compressive strength and torsional tensile strength of concrete and, on crack of RC and PC structure.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1990.10a
• /
• pp.123-124
• /
• 1990

Seaside concrete structure is deteriorated by chloride-ion, sulphate and salt cristalization in concrete pore. Therefore the amount of these chemical substance should be analyzed for evaluating the durability of seaside concrete structure. In this study, the amount of chloride-ion in concrete was surveyed in order to estimate the damage state of concrete structure within am influence of seawater.