• KIEAE Journal
• /
• v.8 no.5
• /
• pp.55-60
• /
• 2008

The purpose of this study is to increase the use of Hwangto and examine the strength according to what it is compounded with. Hwangto-concrete containing Hwanto without cement nor organic chemical products were compared to the traditional cement concrete through some durability experiments. We expect to gain more knowledge on the potentials of Hwangto-concrete as an architectural source. 1) As Hwangto binder amount rises, the value of slump increases too. The reason is that the increase of the quantity of cement causes the increase of the amount of material and the decrease of the amount of aggregate. 2) When the mixed component into Hwangto-concrete remains at 2%, the compress strength is generally dispersed high along the per unit fission, in case the amount of which is at $400(g/m^3)$. The highest compress strength is 39MPa. It means that it can be applied to common structures and we need to conduct a basic property test to ensure the strength and fluidness. 3) Hwangto-concrete is expected to be highly used in the ocean structure and chemical industry because it has better resistance to sulfuric acid and to hydrochloric acid than the cement-concrete has. The result of this study is as follows. It is expected that Hwangto-concrete will be widely applied and further research on its durability and tests for its basic substantial characteristics based on future component added to it.

• Architectural research
• /
• v.11 no.1
• /
• pp.25-33
• /
• 2009

This study presents the testing of 15 hwangtoh-based cementless concrete mixes to explore the significance and limitations of the development of eco-friendly concrete without carbon dioxide emissions while maintaining various beneficial effects. Hwangtoh, which is a kind of kaolin, was incorporated with inorganic materials, such as calcium hydroxide, to produce a cement-less binder. The main variables investigated were the water-to-binder ratio and fine aggregate-to-total aggregate ratio to ascertain the reliable mixing design of hwangtoh-based cementless concrete. The variation of slump with elapsed time was recorded in fresh concrete specimens. Mechanical properties of hardened concrete were also measured: including compressive strength gain, splitting tensile strength, moduli of rupture and elasticity, stress-strain relationship, and bond resistance. In addition, mechanical properties of hwangtoh-based cement-less concrete were compared with those of ordinary portland cement (OPC) concrete and predictions obtained from the design equations specified in ACI 318-05 and CEB-FIP for OPC concrete, wherever possible. Test results show that the mechanical properties of hwangtoh-based concrete were significantly influenced by the water-to-binder ratio and to less extend by fine aggregate-to-total aggregate ratio. The moduli of rupture and elasticity of hwangtoh-based concrete were generally lower than those of OPC concrete. In addition, the stress-strain and bond stress-slip relationships measured from hwangtoh-based concrete showed little agreement with the design model specified in CEB-FIP. However, the measured moduli of rupture and elasticity, and bond strength were higher than those given in ACI 318-05 and CEB-FIP. Overall, the test results suggest that the hwangtoh-based concrete shows highly effective performance and great potential as an environmental-friendly building material.