These two sessions will explain how silica fume lends to heightened sustainable and resilient construction. License design professionals, contractors, producers, and students will learn how silica fume lends to the overall lowered embodied carbon in structures. Topics will include extending service life through enhanced durability with silica fume, reducing member size in design when using silica fume concrete, increasing particle packing in concrete mixtures (SCC and HPC), and reducing water and cementitious material content when using silica fume in concrete pumping. In addition, case studies will exemplify the lowered embodied carbon and sustainable and resilient benefits to construction projects.
(1) Sustainable and resilient design requires an integrated, long-term holistic view of all phases of the project: planning, designing, constructing, maintaining, operating, repair/rehabilitation, then final decommissioning and disposal at the end of its service life;
(2) Silica fume can assist in mitigating distress mechanisms that shorten the life of structures or increase the cost of ownership through increased maintenance or repairs;
(3) Enhancing structures' robustness, durability, longevity, disaster resistance, and safety can be accomplished with silican fume concretes, construction practices, and appropriate inspection and maintenance strategies;
(4) The increased emphasis on life cycle cost analysis (LCCA) for projects requires attention to the service life and durability of concrete structures, including costs of initial construction, continued maintenance, and eventual demolation or deconstruction.
Concrete for a Millennium
Presented By: Robert Lewis
Affiliation: Ferroglobe PLC
Description: In 1988 a request was made for a concrete that would last 1,000 years, to be placed, by volunteer labor, some 8,7000 feet up in the Rocky Mountains. This was at least an hour run from the nearest ready-mixed concrete plant and the concrete would have to be manhandled up the hill from the end of the road. This was to be a religious edifice, a place of worship, venerating a key person of the Buddhist community. It would be a solid construction of large concrete elements and feature delicate facia decoration to make it beautiful to behold. Being pre-Life 365 and high powered PCE’s, designing such a concrete had no precedents, and many deemed it impossible. However, a few concrete technologists called up some formulas and equations and began work. This is the story of The Great Stupa of Dharmakaya.
Enhance Resilience and Sustainability by Incorporating Silica Fume to Improve Performance and Increase Service-Life
Presented By: WILLIAM THOMPSON
Affiliation: GCP APPLIED TECHNOLOGIES
Description: As there is increased focus on global greenhouse gas generation and particularly the current level of CO2 liberated by the production of portland cement, the cement and concrete industry has made commitments to make continued improvements with the goal of achieving carbon neutrality over a relatively short period. The National Ready Mixed Concrete Association (NRMCA), American Concrete Association (ACI) (which recently established NEU: An ACI Center of Excellence for Carbon Neutral Concrete) and others, are supporting the Portland Cement Association (PCA) Roadmap to Carbon Neutrality and the Global Cement & Concrete Association Roadmap to Zero.
These commitments have and will increasingly result in; changes to portland cement, use of increased volumes of existing Supplemental Cementitious Materials (SMC), introduction of new SCMs and pozzolanic materials as well as non-hydraulic cement. Many of these changes will generate the need for strength enhancement, reduction of size and volume of concrete elements as well as durability and extension of design-life of concrete structures and pavements. Silica Fume should and will play an important part in each of these areas.
The proposed presentation will concentrate on the following:
1. The negligible, 1-2 kg/m3 (1.7-3.4 lb/yd3) CO2 contribution of Silica Fume in concrete.
2. Benefit of the use of post-industrial by-products such as Silica Fume.
3. The significant improvement to concrete performance and heat reduction in Silica Fume concrete when combined with other SCMs.
4. Reduction in dimensions and weight of structural members using Silica Fume concrete.
5. Potential for reduction of the volume of reinforcing steel in structures containing Silica Fume.
6. Ability of Silica Fume to enhance the early and ultimate strength of concrete mixes containing higher volumes of limestone, inert materials and less reactive pozzolans.
7. Dramatic increase in durability, density, permeability and extension of service-lifE.
Sustainable Concrete Pavements with Blended Cements
Presented By: Julie Buffenbarger
Affiliation: Beton Consulting Engineers
Description: Transportation infrastructure management has traditionally focused on the safety and reliability without deliberately incorporating sustainability considerations. Recently, national, state and municipal governing bodies, the engineering community and society as a whole, are realizing the enormous investment of materials, energy, capital, and social costs affiliated with infrastructures system design, construction and maintenance. Approaches to help achieve higher infrastructure sustainability and resiliency include design and construction techniques to provide longer-lasting pavements, use of recycled materials in construction, and increasing the use of supplemental cementitious materials (SCMs) and portland limestone cements in concrete mixture designs. Concrete materials manufactured with blended cements intrinsically reduce greenhouse gas emissions by reducing portland cement usage. In addition, blended cement concretes containing SCMs may substantially increase the pavement service life providing the most cost-effective method to reducing the economic, environmental and societal impacts (triple bottom line) of surface transportation.
Performance-Based Concrete Mixtures for Durable, Long-Life Bridges
Presented By: Kevin MacDonald
Affiliation: Beton Consulting Engineers LLC
Description: Worldwide, the state of transportation infrastructure has reached a critical stage. Aging bridges and other infrastructure assets are currently supporting the demands of increases in use far beyond the originally engineered capacity and well beyond the intended service life expectations.1-2 With this increased capacity and usage -in conjunction with increased climate change instabilities (natural or man-made) comes accelerated deterioration of bridges and the compromised safety of its users.
Capital investment of new infrastructure systems is economically intensive. Transportation agencies are challenged to plan, build, and operate “sustainable” transportation systems that – in addition to achieving the important goals of mobility and safety – support a variety of asset management, environmental stewardship, climate mitigation/adaptation, and resilient infrastructure objectives.
Concrete is one of the most widely used building materials in the construction of infrastructure. Approaches to help achieve higher concrete infrastructure sustainability include design and construction techniques to provide longer-lasting structures, increasing the use of supplemental cementitious materials (SCMs), and most importantly enhancing the durability and increasing the service life.
Two US projects, a concrete-segmented, cable-stayed bridge and an extradosed bridge utilizing performance-based concrete mixtures to meet expedited constructability, enhance long-term durability and increase service life are discussed.