GLENDALE : Teen Scientist Faults Concrete for Quake Loss

Eighth-grader Linda Khatchaturian was looking for a concrete way to honor her Armenian ancestors and to help the country devastated by an earthquake in 1988.

Linda’s Armenian grandparents escaped from the Soviet Union to Iran. Her parents moved from Iran to the United States just before she was born 14 years ago.

Linda, who researched Armenia’s history as a student at Chamlian Armenian School in Glendale, decided to try to discover why many concrete buildings crumbled to the ground in the Dec. 7, 1988, disaster. The quake, which measured 6.8 on the Richter scale, killed more than 55,000 people in Armenia.

Her concern led Linda to win first prize last month in the junior division, applied mechanics, of the California State Science Fair for an experiment testing the effects of temperature and cement content on concrete.

Using a myriad of concrete samples with different variations of gravel, sand and cement--the major components, along with water, of concrete--Linda showed that concrete buildings deteriorate quickly in climates as cold as Armenia’s unless extra cement is used in the structure.

Most buildings in Armenia were built of concrete, but because the Armenian government--then part of the Soviet Union--had little money and cement was very expensive, it skimped on the amount of cement used in the mix. This, in conjunction with construction during cold weather, further weakened concrete structures, Linda concluded.

She suggested that Armenian contractors find some way to heat sand and gravel in concrete to ensure the water content does not freeze, expand and break the concrete. Linda is the first of Chamlian’s 430 first- through eighth-grade students to win a state science competition, said Chamlian Principal Vazken Madenlian. She will graduate from Chamlian next week and attend Providence High School in Burbank in the fall.

The teenager, who wants to become a pediatrician and to visit Armenia some day, used two tests in her experiment.

In Test A, Linda placed three samples--all containing two parts sand to three parts gravel to two parts cement--in the oven at 110 degrees, three in the freezer at 30 degrees and three outdoors at between 60 and 70 degrees.

She allowed the samples to cure for 24 hours, took them outside and left them for 20 days then took them to a lab and used a professional press to test their strength.

When the samples she had frozen crumbled under the weight of the press, Linda proved the first part of her hypothesis: Because Armenia has an unusually cold climate, buildings were built in cold weather out of necessity, weakening the concrete’s strength.

Water used to keep the sand, gravel and cement moist for better mixing had expanded in the frozen samples, cracking the concrete, she said.

For test B, Linda changed the cement content in each of three samples that used varying proportions of sand, gravel and cement.

She left these samples outside for 20 days and then took them to the lab to test them with the press. The tests showed the second portion of Linda’s hypothesis was correct: The sample with the most cement was the strongest.