Includes Bibliographical References

This study was conducted to determine the effect of sizes of uncrushed gravel on the compressive strength of concrete. The gravels used were taken from Galungan River Quarry at Bulaga, Aluling, Cervantes, llocos Sur to Arena, Tadian Campus, Tadian, Mountain Province for the study.
The measuring, mixing, pouring and curing of concrete cylinder samples were conducted at the Arena, Tadian Campus; while the testing was conducted at the Provincial Engineering Office Laboratory, Bontoc, Mountain Province.
Based from the results of the test, uncrushed gravel passing through % inch sieve and retained at inch sieve (maximum size) has the highest mean compressive strength (13.205 MPa) compared to the other sizes. The analysis of variance also showed that there is a significant difference among the different gravel sizes. Further analysis using Scheffe's Test explained that there are no significant differences of the means between T,T2 and Ta. This means that the uncrushed aggregate sizes of % inch, 1 inch and unsieved gravels give more likely the same compressive strength.
In the light of the results and conclusions of the study, the researchers are recommending that uncrushed aggregate sizes of 4 inch, 1 inch and unsieved gravels be used for construction purposes. Moreover, further study on concrete samples using another Universal Testing Machine (following the correct procedure) is recommended.

Bachelor of Science in Civil Engineering