(March, 2019)
9”x7”x4”
The Concrete
Infrastructure was built to be destroyed, and therefore seen. A mixture of Portland cement, gravel aggregate, and water was formulated for efficient curing and hardening, cast, and soaked in a heated, supersaturated salt solution for two months. Its surface is peeled and crumbling, and salt crystals have grown, taking advantage of the loss of integrity. Infrastructure breakdown makes visible the hidden constructions that create and delineate space within the built environment, maintaining societal or personal function. Cement, through its presence in concrete structures, is utilized to manipulate the interface between beings and the built environment, controlling the way the geologic exists in both time and space, forcing it into determined forms and a human’s timescale. This depends on a concrete’s formulation. Structures of Roman cement, crafted from hydrated lime and volcanic ash, set and hardened slowly, haven’t shown a single crack in two thousand years1. Seventy eight human generations. Modern concrete structures, produced from energy-intensive Portland cement, are designed for a fifty year service life[1]. Two human generations. In an urban, coastal environment like Houston, they deteriorate in twenty to thirty years1 under the action of heavy use and saltwater. One human generation.
Cement is a cycle masquerading as a state. It reduces stone formed over millions of years to its base elements, hydrates and reforms them in a weaker, less stable arrangement, from which they eventually crumble back into dust[2]. This cycle is not self-contained; its boundaries are not crisp, muddied by affecting and being affected by its environment. It is permeable, able to be infiltrated, while simultaneously pervasive, emitting contaminants and impurities under chemical, thermal, or physical stress[3]. The thing that builds also degrades.
Multiple research groups have voiced concern over cementitious materials leaching toxic trace metals into water used by humans. Vanadium[4] has been shown to leach from the surface of poorly cured concrete, while arsenic, beryllium, cadmium, chromium, mercury, nickel, lead, antimony, selenium, and thorium have been shown to leach in detectable concentrations from all cured Portland cement when crushed and agitated3,[5],[6]. CaO, SiO2, Al2O3, manganese, zinc, barium, arsenic and other heavy metals are the main components[7] that leach heavily from commercial cement into saline water, as seen in the concrete structures along the Houston coast. These heavy metals are also present in the crystals of Infrastructure, leached from its weak matrix by its heated, corrosive solvent.
Cement dust stifles life, reducing plant cover, height, and leaf generation in a variety of taxa[8]. It clogs the plants’ pores and produces active growth reduction, not just suppression of future growth. It shapes the biosphere around it in a way that is actively designed; altering soil pH, it affects which plants grow where, forest and ecosystem strata, and manipulates the use of these ecosystems by animals and humans. Cement dust emitted by manufacturing plants contains toxic compounds7, mostly heavy metals: fluoride, magnesium, lead, zinc, copper, beryllium as well as hydrochloric and sulfuric acid. In its solid state and throughout its creation and deterioration, cement permeates and is permeated by its environment.
The cement that makes up the infrastructure of the built environment is the geologic forced into a human timeframe, its destruction or dissipation hastened by the manipulation of its form. This begs the question: which structures within the environment will exist beyond this timeframe? What could a planetary infrastructure look like?
<< 1. Miasma ----- 3. Lamina >>
[1] Mehta, P. K. (2001, October). Reducing the Environmental Impact of Concrete. Concrete International, 61–66.
[2] What’s the Difference Between Cement and Concrete? (n.d.). Retrieved March 2, 2019, from Concrete Contractors Association of Greater Chicago website: https://www.ccagc.org/resources/whats-the-difference-between-cement-and-concrete/
[3] Hillier, S. R., Sangha, C. M., Plunkett, B. A., & Walden, P. J. (1999). Long-term leaching of toxic trace metals from Portland cement concrete. Cement and Concrete Research, 29(4), 515–521. https://doi.org/10.1016/S0008-8846(98)00200-2
[4] Lu, H., Wei, F., Tang, J., & Giesy, J. P. (2016). Leaching of metals from cement under simulated environmental conditions. Journal of Environmental Management, 169, 319–327.
[5] Kanare, H. M., & West, B. W. (1993). Leachability of selected chemical elements from concrete. Presented at the Symposium on Cement and Concrete in the Global Environment, Chicago, Illinois.
[6] Rankers, R. H., & Hohberg, I. (1991). Leaching tests for concrete containing fly ash - evaluation and mechanism. London, UK: Elsevier Science.
[7] Yang, Z., Ru, J., Liu, L., Wang, X., & Zhang, Z. (2018). Long-term leaching behaviours of cement composites prepared by hazardous wastes. RSC Advances, 8(49), 27602–27609. https://doi.org/10.1039/C8RA02773K
[8] Iqbal, M. Z., & Shafig, M. (2001). Periodical Effect of Cement Dust Pollution on the Growth of Some Plant Species. Turkish Journal of Botany, 25, 19–24.