Master Builders mixes mortar for Manhattan monarchs

Material science behind lightweight concrete and self-consolidating mixtures yields a principal element of the Monarch Sanctuary, a 15-ft. “vertical butterfly meadow” prototype on display at the Cooper Hewitt Smithsonian Design Museum, New York City.


Built from wood, plastic, and high performance mortar, the Monarch Sanctuary will be on display at the museum, located on 91st Street at Fifth Avenue in Manhattan, through early next year. Exhibit sponsor BASF summarizes prospects for the Sanctuary template in real world architecture: “Thanks to art, design and chemistry intersecting in one project, a community will one day be able to look out their windows and see a garden of butterflies—a haven for the monarchs benefit[ting] humans who live and work in and around the building.” PHOTOS: BASF Corp.

The diagrids’ energy and material efficiency owes to light surface characteristics and strength development from optimized mortar mix design. BASF Construction Chemicals Technical Center scientists cast the mortar elements—flowers (shown here at pouring), squiggly mazes, sand castles and peaks—earlier this spring on a tight timetable dictated by the May 2019–January 2020 Cooper Hewitt Monarch Sanctuary exhibit schedule. Casting necessitated material with spread properties similar to self-consolidating mixes, and included alignment of bracket hardware with which the diagrid elements could be readily mounted on the exhibit’s wooden frames. Live monarchs were brought in to test the initial exhibit layout.

Maze preferred cropPeaks preferred crop

A team from Terreform ONE, a Brooklyn design and architectural firm, sought to craft a habitat that would support monarchs going from larvae to chrysalis to adult butterflies that lay eggs and reset the whole cycle, and provide them a way station and opportunity to have their population restored in a dense urban environment. BASF Corp., sponsor of the Sanctuary and companion Cooper Hewitt Triennial exhibition works, enlisted its Master Builders Solutions unit to formulate a mortar mix for 20 diagrids—paned diamond shapes constructed from interlocking beams, reminiscent of a honeycomb, and bearing curved, circular and triangular geometric forms.

A concrete-like formulation could net white diagrids with characteristics friendly to monarchs such as heat reflectance and nooks to accommodate nectar sponges. “We agreed upon the design intent and specifications for the material: [It] needed to be lightweight, white-colored, extremely flowable and raise the bar on sustainability characteristics,” notes Terreform ONE Executive Director Vivian Kuan. “BASF rose to the challenge, taking our designs and then figuring out how to achieve mutual goals.”

BASF Construction Chemicals Product Development Manager Dr. Lesley Suz-Chung Ko and colleagues developed a specialty mortar with fine aggregate, portland cement, supplementary cementitious material and water, plus Master Builders Solutions Products. Mimmicking Self Consolidating Concrete mixes, the diagrid material proved equal to creating uniform surfaces and intricacies indicative of 3D-printed silicon molds Terreform ONE shipped to the BASF Construction Chemicals lab outside Cleveland. With 2-ft. sides and geometric forms 2- to 6-in. deep, the Sanctuary elements weigh between 20 and 40 lbs.

The Monarch Sanctuary provides a template for a ground level-to-roof structure accompanying an eight-story building planned in Manhattan’s Nolita neighborhood, and envisioned as a breeding ground for monarch butterflies, populations of which have dwindled in the Big Apple. — Adapted from a report by Laura Buchwald and Anna Spiewak of BASF Corp., Florham Park, N.J.

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