It didn’t matter whether Caitlin Clavette was teaching Milton students about classic painting, biking the last mile of a triathlon, or volunteering with abused animals. She brought the same joy and enthusiasm to all her endeavors, according to those close to her.

Clavette, 35, was killed Friday when a manhole cover on the Southeast Expressway became airborne and crashed into her car. Friends and family are preparing to lay her to rest this week and remembering her as an enthusiastic elementary school teacher, a determined athlete, and an encouraging teammate.

A funeral Mass will be said at 11 a.m. Tuesday at Saint Eulalia Parish in Clavette’s hometown of Winchester. She will be buried at Mount Pleasant Cemetery in Arlington, the town where she lived.

“When I think of her, one of the things I think about is her constant smile,’’ said Anne Traer, one of Clavette’s teammates on a Boston-area triathlon group. “She could be running at her race pace and if she saw you, she’d still smile.’’

In lieu of flowers, the family has asked that donations be made to the Massachusetts Society for the Prevention of Cruelty to Animals, where Clavette often volunteered. She loved animals, including her cat, Gizmo, her family wrote in a death notice printed in The Boston Globe.

State Police are investigating the event that caused her death.

Clavette taught art in elementary schools for several years, first in Scituate and then in Milton, where she worked since 2011.

In a letter to parents Friday afternoon, Milton Public Schools officials said Clavette’s death was a “tremendous loss.’’

“She was a talented and valued member of our faculty,’’ wrote the principal of Glover Elementary School, Sheila Kukstis, in a message to the school community. “Our thoughts and prayers are with her family and friends.’’

Clavette graduated from Winchester High School and received her bachelor’s degree in art from the College of William and Mary in Virginia. She held a master’s degree in teaching from Tufts University in conjunction with the School of the Museum of Fine Arts in Boston.

An athlete since her time on the varsity lacrosse, soccer, and indoor track teams in high school, Clavette also enjoyed competing in triathlons. She joined the Wheelworks Multisport Triathlon team three years ago and was already winning races in her age group.

But what really made her a great team member was how she was always cheering for others, Traer said.

“She had a tremendous positive impact on so many people,’’ Traer said.

Mike Nislick, another triathlon teammate, said Clavette’s caring personality was clear from the first time he met her.

Team members were having dinner together when they saw a bird lying on the sidewalk. Clavette was immediately concerned, Nislick recalled.

She contacted several rescue groups, and eventually decided to care for the bird herself. She tried to coax the bird into a box to carry it home, but it flew away. It turned out the bird was fine.

But the incident reflected Clavette’s compassion, Nislick said. “It’s a thing that really stood out as a first impression — what a kind and sweet person she was,’’ he said.

Traer said she is reeling from Clavette’s death.

“It’s shocking and horrible when someone so vibrant and so young is lost in just a senseless tragedy,’’ Traer said.

Aneri Pattani can be reached at aneri.pattani@globe.com.