4.7.7 Green Concrete

• There are three types of green concrete including – functional concrete– eco-concrete – recycled concrete

• In eco-concrete there are– permeable concrete– virescence concrete – sound absorption concrete

• Functional concrete has been introduced in the previous sections. We will focus on – virescence concrete– recycled concrete

Introduction

Virescence Concrete

• Virescence concrete is suitable for plant, vegetation and its products.

• There are 3 types: – Virescence concrete with holes

• It is designed to leave holes in the block for plant

– Virescence concrete with connected pores• It contains connected holes to provide spaces for root gro

wth and nutrient absorption

– Virescence concrete with holes in multilayers• It is made out of concrete with holes added by cavities an

d multilayers

Fig.4.7.12 Structure of Green Concrete

Fig.4.7.13 Virescence Concrete with Holes in Multilayers

• The upper layer is concrete with holes and cavities but the lower layer is concrete with holes not cavities.

• The two layers are glued together to form the space for earth filling.

• It is applied in parts, which has no direct connection with earth, for example, on the balcony in apartment buildings and top of the wall of the yard in the city.

• It can enlarge the green area in the city and make it more beautiful.

Virescence Concrete with Holes in Multilayers

Recycled Concrete

• Recycled concrete refers to the concrete whose aggregate or part of aggregate are made of recycled aggregate.

• Lots of waste will be produced when buildings are torn down.

• They take up much room and bring unhealthy effects on the environment.

• They can be processed by washing, cracking and setting to produce concrete aggregate called recycled aggregate.

Tab.4.7.12 Definitions of Architectural

Waste in Foreign Countries Country Definition

Canada Construction waste: waste in every phase

Japan

Building Cube Sand and stone dug up can be recycled

Building waste

Recycled: concrete, damp concrete, silt, paper, metal and used wood

Non-recycled: poison waste, disseminated

USA

Unpolluted solid waste from cleaning of new construction, maintenance, reconstruction, tear-down, farm clearing-up, public property maintenance and seasonal or natural disasters.

Recycled aggregate

• Process: Scrap the aggregate then crack with jaw

crusherThe distance between jaw boards is sim

ilar with that of natural coarse aggregate

• Features:lower than natural aggregate specific

gravityhigher water absorption

• Standard: Referred to the requirements of natural aggr

egate (JGJ53-92)

Recycled aggregate

Fig.4.7.14 Natural and Regeneration Coarse Aggregate Gradation Curve

020406080100

0 5 10 15 20 25 30

(mm)筛孔尺寸

(%)

通过

百分

数RCA1RCA2RCA3NA1

Fig.4.7.15 Ordinary Concrete and Regeneration Concrete Strength Curve

01020304050

0 10 20 30 40 50 60 70 80 90 100

( )龄期 天

(MPa)

强度

N50000R50000N60000R60000N70000R70000

Fig. 4.7.16 Fly Ash-added Recycled Concrete Strength Curve

0

10

20

30

40

0 10 20 30 40 50 60 70 80 90 100

龄期（天）

MPa

强度

（） N60000

R60000R61000R62000R63000

Chapter 4