Innovations in materials are influencing contemporary architectural practice. Today, the focus is primarily on new materials that exhibit enhanced properties. Therefore, advanced and composite materials, smart and responsive materials, and biologically inspired materials are gaining popularity in architectural design. Advanced materials are those that have enhanced properties (such as thermal performance, structural properties, durability and so on), and exhibit sensitivity to the environment in terms of production and use. Smart and responsive materials are those that exhibit properties that can be changed or altered, so that they act as sensors or actuators, responding to changes in the environment. These new emerging materials offer radical changes to the built environment in terms of energy usage, thermal behaviour, structural performance and aesthetics. This chapter provides an overview of emerging materials and discusses their use, performance, benefits and drawbacks.
Advances in physical sciences have led to a new understanding of changeable materials, particularly those compromising the acoustic, luminous and thermal environments of buildings. A smart structure can be defined as a non-biological physical structure that has a definite purpose, means and imperative to achieve that purpose, and a biological pattern of functioning. Smart materials are considered to be a subset, or components of smart structures, and act in such a way as to mimic the functioning of a biological or living organism and adapt to changing conditions in the environment. Smart materials can be classified into two general categories â materials that can sense and inherently respond to the changes in the environment, and materials that need control in a systematic manner in order to actuate based on a certain change. Different types of smart materials include piezoelectric, electrochromic, electrostrictive, magnetostrictive, electrorheological, shape-memory alloys and fibre-optic sensors. Piezoelectric materials exhibit significant material deformation in response to an applied electric field and produce dielectric polarisation in response to mechanical strains. Electrostrictive materials exhibit mechanical deformation when an electric field is applied. Magnetostrictive materials generate strains in response to an applied magnetic field. Electrorheological materials exhibit the âER responseâ or âWinslow effectâ, which refers to a significant and reversible change in the rheological behaviour of fluids subjected to an external applied electric field â low viscosity fluid converts into a solid substance. Shape-memory alloys are metal compounds that can sustain and recover large strains without undergoing plastic deformation under externally applied stress or thermal changes.
ADVANCES IN CONCRETE
Transforming the design and construction industries are new advances in concrete- and cement-based products. Among many new materials being used are superplasticising admixtures, high-strength mortars, self-compacting concrete and high-volume fly ash and slag concretes. A number of advances in new concrete technologies have been made in the past decade, including materials, recycling, mixture proportioning, durability and environmental quality. There are also diverse new methods and techniques in todayâs construction world, such as high-performance concrete (HPC) and fibre-reinforced concrete (FRC). Advanced composite materials have become popular in the construction industry for innovative building design solutions, including the strengthening and retrofitting of existing structures. The interface between different materials is a key issue of such design solutions, as the structural integrity relies on the bond between different materials. Knowledge about the durability of concrete/epoxy interfaces is becoming essential, as the use of these systems in applications such as fibre-reinforced plastic (FRP) strengthening and retrofitting of concrete structures is becoming increasingly popular.
Recycled materials are usually added to HPC, thereby reducing the need to dispose of them.1 Some of the materials include fly ash (waste by-product from coal burning), ground-granulated blast-furnace slag and silica fume. But perhaps the biggest benefit of some of these other materials is the reduction in the need to use cement, also commonly referred to as Portland cement. The reduction in the production and use of cement has many beneficial aspects, including a decrease in the creation of carbon-dioxide emissions and energy consumption. In addition, fly ash and furnace slag have properties that improve the quality of the final concrete and the use of them is usually more cost-effective than cement.
Todayâs concrete technologies have produced new types of concrete that have lifespans measured in the hundreds of years rather than decades. When compared with standard concrete, new concretes have better corrosion resistance, equal or higher compressive and tensile strengths, higher fire resistance, and rapid curing and strength gain. In addition, the production and life ...