4.7.3 High Performance Concrete (HPC)

1. 4.7.3 High Performance Concrete (HPC) • Introduction • Characteristics • Techniques • Proportion ratio • Properties • Application

2. Introduction • HPC refers to excellent materials made by strict construction craftworks, It is convenient to cast and compact with no segregate It is steady in volume and mechanical property. • ACI international conference first proposed that high performance concrete can’t be made by regular materials and technology to meet synthetic properties and uniformity in 1990. • It has good performance in toughness, durability. • It can be applied to high architectures, bridges and those exposed in harsh environment.

3. Characteristics • HPC is a new kind of concrete with great feasibility, high strength and durability. • Its characteristics are as follows: • The concrete mixture has good performance in mobility, self-impact and can ensure uniformity and impact with slight vibration or without vibration. • The concrete mixture shows good cohesion, water retentivity, plasticity, stability and pump ability with no segregate in water. • It can be used in mass concrete casting because low hydration heat is produced in the process of setting and hardening. • It can keep volume steady and have small shrinkage deformation after hardening, so there are few defaults such as micro cracks inside concrete and it forms a stable structure.

4. Characteristics • Its characteristics are as follows: • It has good protective ability of reinforced bars in concrete in high solidity and strong resistance of permeability of water, corrosive liquid and chlorineion. • It contains little Ca(OH)2 and hydrated calcium sulfate, which are easy to be eroded by sulfate and magnesium to ensure the resistance to seawater corrosion. • Concrete has excellent permeability and proper content of gas with even and impact bubbles so it has good performance in freeze-thaw resistance and fastness to efflorescence. It is easy to be cast for the concrete structure in the area which can be touched by waves. • It can be used in prefabricated concrete for its high strength and lower content of binding material, which is less than that in ordinary concrete.

5. Techniques • Selection Cement with medium heat, MDF, DSP; super fine mineral admixture; superplasticizer; Dmax<15mm. • Parameter W/ C<0.4, W<175; Sp=36-42%; binding material=500-600 • Craft works control Forced mixing, high frequent vibration; pumping up, SL>200; protection in early days

6. Tab.4.7.2 Proportion Ratio

7. Properties • Comparison of Properties (Tab.4.7.3) • Dry Shrinkage (Tab.4.7.4) • Time and the Slump Loss (Tab.4.7.5)

8. Tab.4.7.3 Comparison of Properties

9. Tab.4.7.4 Dry Shrinkage

10. Tab.4.7.5 Time and the Slump Loss

11. Application In foreign countries: • German concrete structure design has reached to C110 • In Norway C105, HPC in 85～90 is widely used in road construction • Denmark Belt-connection between tunnels and bridges • Designed for 100 years • Applied in tower structure, prefabricated beam and block • Japan • Super strength and high performance concrete for apartment buildings • Super durable concrete over 500 years has been developed

12. Application In China： • Shanghai Jin Mao Tower C60 • Beijing West Railway Station C60 • Beijing Jing’an Center C80 • Liaoning Goods and Material Mansion C80 • Nanjing Posts and Telecommunications Center C60 • Changchun International C55 • Guangzhou Humen Bridge C50 • Shanghai Yangpu Bridge C50 • Steel concrete for Changjiang River Bridge Wanxian County C60