Betão Leve de Elevado DesempenhoHigh Performance Light Weight Concrete

Universidade do Minho Departamento de Engenharia Civil

Grupo: Mattos, C. Guimarães , Charles, E. Guimarães , Alshaghel

21/11/2015

OUTLINE : Introduction Definition- What is HPC Ingredients Properties Application Contribution to sustainability Conclusions

Introduction

Introduction

High performance ≠High strength

Regarding it as high Performance concrete :• High strength• High workability• High durability

Concrete is the most used material in the world by the human kind ..after water

Many kinds and types ..several options

• Economical advantages

INTRODUCTION

• High performance concrete exceeds the properties of normal concrete

• Specific characteristics • For Special environments and applications • To give excellent performance in the structure

INTRODUCTION

Heavyweight HPC Fiber reinforced HPC

Confined HPCLightweight HPC

High performance Concrete

Conventional Concrete

Light weight Concrete

Properties ?

HPLC is a concrete, which meets special performance, and uniformity requirements that cannot be always achieved by using only the conventional materials and normal mixing, placing, and curing practices, also it consist lower density (light aggregate)

Definition What is HPLC

HPC is a concrete in which some or all of the following properties have been enhanced (a) Ease of placement (b) Long term mechanical properties (c) Early age strength (d) Toughness(e) Density

Ingredients

Selecting High Quality Materials

• Cement• Fine aggregate• Coarse aggregate• Water• Mineral admixtures • Chemical admixtures

PROPRIEDADES

Betão Leve – γ < 2000kg/m³

Referência Massa específica (kg/m³)

RILEM (1975) γ < 2000CEB-FIP (1977) γ < 2000

NS 3473 E (1992) 1200 < γ < 2200ACI 213R-87 (1997) 1400 < γ < 1850CEN prEN 206-25

(1999)800 ≤ γ ≤ 2000

Betão Leve de Elevado Desempenho γ < 2000kg/m³ a/c < 0.4 elevada trabalhabilidade alta resistência elevada durabilidade

Composição Química

Agregrado grosso – leve argila expandia vermiculita xisto Ardósia

Agregado fino – convencional Aglomerante – CEM I 42.5 / 52.5

400 kg/m³ - 600 kg/m³ a/c < 0.4 Superplastificante Adições minerais: cinzas volantes,

silica ativa, metacaulino.

Propriedades Mecânicas

Betão como material compósito Lei das Misturas

Resistência à compressão do agregado grosso Resistência à compressão da matriz cimentícia

Resistência à compressão do BLED – favorável quando há proximidade entre as rigidezes dos seus constituintes

“Os agregados leves diminuem sua resistência à compressão com o aumento da sua dimensão” (Rossignolo, 2003)

Resistência à tração do BLED – inferior à do não leve

Módulo de Elasticidade do BLED – inferior ao do não leve

Propriedades fisico-químicas e limitações

Permeabilidade Densidade

Porosidade [-]

Trabalhabilidade

Condutividade térmica

Durabilidade

Resistência à compressão atinge valores mais baixos Menor Rigidez

Vantagens:

Baixos custos Redução do tempo de montagem Fácil manuseamento

APLICAÇÕES

Pré-fabricados

Chateau on the Lake, Branson, EUA Wellington Stadium, Wellington, Nova Zelândia Ponte James River, Richmond, EUA

Resistência à

compressão (MPa)

Massa específica (kg/m³)

41 γ = 1850

35 γ = 1850

35 γ = 1850

OUTRAS APLICAÇÕES

In loco

Ponte Nordhordland, Noruega Museu de Guggenhein, em Bilbau,Espanha Tanque South Arne, Noruega

Vantagens

Propriedas flutuantes Baixo peso

Resistência à

compressão (MPa)

Massa específica (kg/m³)

70 γ = 1900

25 γ = 1600

45 a 60 1850<γ <2250

CONTRIBUTION TO SUSTAINABILITYHistory

The benefits that have made using lightweight aggregate (LWA) economical for nearly 100 years are the same characteristics that make the material what is now being called “sustainable.” The use of LWA helps designers, contractors and owners optimize the design, construction and long-term performance of concrete structures.

LWA has been contributing to the sustainability of the site and structure of building projects long before the current green movement came to the forefront.

Lightweight aggregate stands on a 2000 year old Foundation of Sustainability.

Roman period: The first known use of lightweight concrete occurred more than 2000 years ago. There are several lightweight concrete structures in the Mediterranean region, but the three most notable structures were built during the early Roman Empire and include the Port of Cosa, the Pantheon Dome, and the Coliseum.

Masonry

Another early “sustainable” application that is still used today is the 1923 development of lightweight concrete masonry with a higher insulation value, normal shrinkage, ease of handling and a uniform compressive strength equal to normal weight concrete masonry.

the first sustainable case study for lightweight concrete. The Port of Cosa, built about 273 B.C., used lightweight concrete made from natural volcanic materials. These early builders learned that expanded aggregates were better suited for marine facilities than the locally available beach sand and gravel. They went 25 miles (40 km) to the northeast to quarry volcanic aggregates at the Volcano complex for use in the harbor at Cosa. Broken shards of calcined clay vases were also used in the piers.... the first usage of manufactured aggregate.For two millennia they have withstood the forces of nature with only surface abrasion. They only became obsolete because of siltation of the harbor.

Direct sustainable contribution and impact for using light weight concrete.

Thermal Insulation

Fire insulation

Durability

Water absorption

Acoustics properties

Thermal Insulation

Thermal insulation efficiency is defined as resistance to heat flow either through conduction or radiation. Lightweight concrete has a

high heat insulation resistance Such as porous concrete walls 150mm to provide four times better insulation than 225mm thick brick wall.

Fire insulation

Fire prevention is associated with thermal insulationFire Resistance, Lightweight concrete is more fire resistant than

ordinary normal weight concrete because of its lower thermal conductivity, lower coefficient of thermal expansion, and the inherent

thermal stability of an aggregate.

Durability

It is defined as the ability to bear the effects of environment such as the effects of the chemical, physical stress and mechanical effects.

The intended effect of the chemical, including ground water containing sulfate, air pollution and reactive liquid spills.

Water absorption

Absorption water by the concrete is high and more than that found in solid concrete. This is because the lightweight concrete has holes in

it.

Penetration of rain water: it is an important element to the wall.

Acoustics properties

The key factor is the density of the sound insulation material. Therefore for sound insulation, lightweight concrete cannot show the

desired characteristics.

Indirect sustainable contribution and impact for using light weight concrete.

Embodied Energy

Energy performance

Lowering the Environmental Impact of Construction

Sustainability of the Workforce

Internal Curing, Cracking, Elastic Compatibility, and Permeability

Green Roof and Horticulture

Storm Water Management and Water Treatment

Embodied Energy

The embodied energy to manufacture lightweight aggregate includes mining, manufacturing, and transporting the material to the jobsite,

soil blender, or building product manufacturer. The cost of this embodied energy is often paid back in a very short period of time, because less overall material is used, or due to improved thermal

performance, lower transportation costs, and reduction of labor costs associated with the building elements.

Energy performance

The use of LWA lowers the thermal conductivity of concrete and provides significantly better insulating qualities for thermally sensitive applications such as cryogenic applications or high

temperature petroleum storage structures reducing the concrete density increases its thermal resistance.

This energy cost reduction extends over the life of the structure. The life cycle cost savings are many times greater than the potential

higher first cost of the block.

Lowering the Environmental Impact of Construction.

Construction requires transportation! And there is a direct correlation

between transportation, weight and environmental impact. Transportation requirements are directly related to

weight and demonstrate an economic and environmental advantage when

using lightweight aggregate in precast, ready-mix concrete and masonry.

Table 1 includes two trucking studies conducted at a U.S. precast plant. These

studies demonstrated that the transportation cost savings were seven times greater than the additional cost of

lightweight aggregate used to reduce the concrete density. Fewer trucks in

congested cities are not only an environmental necessity but will also

generate fewer public complaints.

Sustainability of the Workforce

Ergonomics. One of the best examples of lightweight concrete and ergonomics is concrete masonry. “Some masons must retire early due to the heavy lifting, and many masons experience crippling back and

shoulder injuries before retirement”. This continual loss of skilled labor is expensive to replace and can hardly be considered

“sustainable or green”.At the same strength, lightweight concrete products are up to 40%

lighter than traditional concrete. Lower weight reduces the physical demands on labor and equipment, resulting in fewer injuries and

worker’s compensation claims, as well as extending equipment life. Repeatedly lifting less weight extends a worker’s career, and allows

women and men to work efficiently.

Internal Curing, Cracking, Elastic Compatibility, and Permeability

Lightweight fine aggregate batched at a high degree of saturation may be substituted for an equal volume of normal weight sand to

provide internal curing in concrete. Field experience has shown that High Strength Concrete is not necessarily High Performance

Concrete and that High Performance Concrete need not necessarily be high strength. A frequent, unintended consequence of concrete

and especially high strength concrete is early-age cracking.

Green Roof and Horticulture.

Lightweight concrete helps to reduce heat island effects by amending soils to improve landscaping and through its use in both intensive and extensive roof top gardens. LWA reduces dead load and is non-toxic, odorless, 100% inert and will not compress, degrade, decompose, or

react with agricultural or horticultural chemicals.Lightweight concrete resists compaction, improves aeration and is

incorporated into engineered structural soil to support healthy plant growth and improve drainage while allowing access by heavy

emergency vehicles to the edges of buildings. LWA enhances soil resiliency to climate changes by reducing nutrient loss and improving

moisture retention.

Storm Water Management and Water Treatment.

The use of lightweight aggregate in site development has assisted designers in addressing the important issue of storm water

management with on-site treatment. LWA can be used to construct vegetated filter strips, rain gardens, rain basins, constructed

wetlands and bios wales to treat and reduce the amount of storm water runoff.

 

CONCLUSÕES

• In the weight, the operational and the economical factor, it is a great alternative

• More HPLC usages are predicted in the civil engineering structures

• the reduced unit mass is a critical advantage.

• higher price of the HPLC is compensated with the construction reduced costs.

• HPLC characteristics as low permeability and high durability significantly extend a structures’ service life

• It cannot be stronger than the normal weight HPC that has the same water/cement ration

• The sustainable role that HPLC play gives it a great advantage

Thank you