Industrial minerals, today and tomorrow; the raw materials to build the upper Midwest [unknown]

P.K. Sims, Sarah Chadima, R.F. Biek, G.B. Sidder
1992 Antarctica A Keystone in a Changing World   unpublished
The significant problems we face today cannot be solved at the same level of thinking we were at when we created them. Albert Einstein Renewing America's infrastructure is more than patching potholes or pushing traffic along a bit faster. The task also bids us to repair the frayed connective tissue, both structural and spiritual, between us as Americans of different races, classes, and beliefs, between our cities, suburbs, and small towns, and between us as humans and our respective biota. We
more » ... pective biota. We need compelling images and principles, not "wish-lists" of projects, to guide public investment and to balance long-term growth in the face of increasingly austere economic and environmental realities and demographic changes. We need confidence that our investment choices will adequately support and sustain an unpredictable economy, as well as our families, our cities and towns, and the surrounding environment. Similarly, we need trustworthy information that our choices do not just divert a set of problems to another region or compound them for the next generation. While a determined chorus of voices intones for more investment, too few people seem to be talking critically and passionately about what a proper infrastructure is and does and what it means for the future. In a nutshell, no amount of capital or concrete substitutes for better understanding. Infrastructure renewal starts with a profound shared commitment to people and to places. The strength of this commitment, along with our individual values, efforts, and aspirations, and collective investment, is manifested in the quality of the public realm. As the commitment erodes, so go our bridges, public parks, and pump storage stations. A more hopeful version was offered recently by a resident of Los Angeles after his community erupted in riots: "We're not into just rebuilding what we had here before.... We want to finally build a community of hope." RESEARCH REQUIRED FOR IMPROVED QUALITY CONTROL Construction aggregates are extensively utilized in infrastructure construction as a "bulk material" or as the major ingredient (on a volume basis) in many "bound materials." Typical bulk material applications are pavement base and subbase layers and railroad ballast and subballast. Some widely used "bound" materials are asphalt concrete, portland cement concrete, and "cementitiously stabilized" mixtures. The pertinent aggregate properties and characteristics essential to ensure acceptable PERFORMANCE vary considerably for different applications. Many State Highway Agencies are in the process of adopting QA/QC programs where the contractor/materials supplier is responsible for the bulk of the physical testing. Rapid, but acceptably accurate and reproducible, test procedures expedite the QA/QC process. When aggregates are utilized in new applications, the testing procedures, specification requirements, and quality control procedures should be carefully considered. Current procedures and requirements may not be adequate, and appropriate and new approaches must be established. An excellent current example is the significant interest in Stone Mastic Asphalt (SMA), where coarse aggregate contact is accentuated. Current developments, quality control concerns, and research needs relating to such pertinent properties as DURABILITY, DEGRADATION, SHAPE-ANGULARITY-SURFACE TEXTURE, and STRIPPING POTENTIAL will be considered.
doi:10.3133/ofr92514 fatcat:ejwotzj6ijf4nlccdubgsgl2x4