Utilization of shredded waste rubber tire as fine aggregate of lightweight concrete / by John Klinton F. Abena and Ian Paul P. Atienza.

Thesis (Bachelor of Science in Civil Engineering) Cavite State University.

Includes bibliographical references.

College of Engineering and Information Technology (CEIT), Department of Civil Engineering

ABENA, JOHN KLINTON F. and ATIENZA, IAN PAUL P. Utilization of Shredded Waste Rubber Tire as Fine Aggregate of Lightweight Concrete. Undergraduate Thesis. Bachelor of Science in Civil Engineering. Cavite State University, Indang, Cavite. June 2019. Adviser: Engr. Cene M. Bago.

Waste rubber tires disposed of in landfills constitute a major environmental issue in all parts of the world. It could also bring serious harm to the health of people living nearby the landfills. Fire hazard is one of the possible serious threats since the cheapest method of tire disposal is by burning. Soil and water can also be polluted because of the oil generated from melting the tires. One of the best ways to lessen the hazard brought by waste rubber tires is by recycling. But to ensure the safety of human welfare, recycled rubbers could not be used for vehicles anymore so humans has to think of different ways to utilize waste rubbers. An alternative way to address such problems is to develop and utilize waste rubber tires as a resource material in making concrete. The main goal of the study was to determine the behavior of concrete with shredded waste rubber tires when used as fine aggregate.

Given that rubber tire itself is already a tough product, chemicals used in manufacturing rubber products made it even better. Four treatments were conducted (0%,10%, 20%, and 30%) and the results revealed that the treatment with fine shredded waste rubber tires had potential to become an alternative aggregate in the construction industry. Utilization of shredded waste rubber tire as a fine aggregate in concrete yielded significant results in terms of increasing the compressive and flexural Strength of the concrete. On the other hand, the researchers found out that freshly mixed concrete with more shredded waste rubber tire was less workable and has slower setting time.

The unit weight of concrete with waste rubber tires was determined and it was considered as lightweight concrete since all the specimens were less than 2200 kg/m? refer to Table 8. It was observed that at the 7" curing day, as the amount of shredded rubber tire increased, the compressive strength also increased. The compressive strength of treatment 1 to 4 at 7" day curing day is 996.67 psi, 1046.67 psi, 1176.67 psi, and 746.67 psi, respectively. Shredded waste rubber tire and compressive strength were also directly proportional in the 28" curing day but its compressive strength decreased on treatment 4 which is 70 percent sand — 30 percent rubber tires. The compressive strength of treatment 1 to 4 at 28" day curing day is 1516.67 psi, 1223.33 psi, 1663.33 psi, and 1340 psi, respectively. On the other hand, the researchers noticed that there was inconsistency with the results of the flexural strength of the beams. Treatment 1 has higher flexural strength than treatment 2. Then, treatment 3 and 4 increased again. The flexural strength of treatment 1 to 4 at 7" day curing day is 273.67 F, 143 F, 288.67 F, and 321.33 F, respectively while at 28" curing day is 414 F, 321.67 F, 293.33 F, and 426.33 F, respectively.

After analyzing the results, the researchers identified that the most economical mixture was treatment 3 which has 80 percent — 20 percent ratio. It showed the highest compressive and flexural strength. Therefore, the researchers observed that the behavior of concrete with rubber tire as a fine aggregate really affects the overall performance of a concrete. Since the rubber tires' fine aggregates were not rounded as sand, it cannot totally fill all the voids to strengthen the concrete.

As per Cavite Testing Center, other types of concrete ratio can be utilized in the future study. Since class A is not always recommended for concrete cylinders and beams.

The use of rubber as a fine aggregate for concrete may be increased for future research to evaluate the limit and its effect on the results of compressive and flexural strength. Lastly, since the researchers conducted paving blocks with rubber as fine aggregate, the results still showed that the 20 percent specimen of rubber has still better compressive strength. So, further study about paving blocks with rubber is also recommended.

Submitted to the University Library 09/19/2019 T-8504