Usability, mechanical characteristics and application criteria of pumice aggregates in the production of high performance lightweight structural concrete

This research study is inspired by artificial lightweight aggregates that have been used successfully in the construction industry abroad for many years. A comprehensive experimental research on lightweight concrete with pumice aggregate, which has wide range reserves in Turkey, was conducted in order to reveal the real performance of pumice aggregate and the availability of similar performance level comparing with using lightweight artificial aggregate. In these experiments; pumice has been investigated especially for the production of high strength high performance concrete. It is aimed to give value to pumice aggregate, which is in the unproductive situation and mostly used for insulation purposes (light block, plaster, etc.) in the construction sector, so as to contribute both to the construction sector with an innovative product and to contribute to the country's economy positively. With the use of the pumice aggregate, the earthquake loads will be reduced with decreasing dead weight of the structural system, which will enable more economical dimensioning of the structural system. It can also be used in the production of the members in the precast sector. In addition, due to the internal curing in concrete, the structural system members will be more durable to environmental conditions, especially civil structures where chloride impermeability is important. In precast elements produced with light-weight concrete, the transportation costs will be affected positively as well. A series of tests were carried out in April 2017-April 2018 with different mixes in R&D Laboratory of a Ready-Mixed Concrete Firm to determine the usability of pumice aggregates for high performance and high strength concrete production. Compared with normal aggregate concrete; physical tests such as slump, flow, unit weight, water absorption, chloride impermeability; and mechanical characteristic tests such as compressive tests on cubes as well as elastic modulus test on cylinders. The results obtained from the experiments have been evaluated together with those ones of artificial lightweight aggregates in the literature. It is realized that when the proper conditions are satisfied, the strength and performance equivalent to those ones of artificial lightweight aggregates can be achieved. Using pumice aggregate, 40-60 MPa cylinder strengths, elastic modulus above 20 GPa and chloride permeability less than 1000 Coulombs have been reached. While the results obtained in this study are the first one for the national literature, it is thought that it will find its place in the international literature. In the First Chaper of this Thesis, the literature survey, the purpose and method of this study used are given. In the Second Chapter; historical development of lightweight aggregate types and technologies as well as architectural applications are handled. In the Third Chapter; lightweight aggregate types and technical properties, artificial lightweight aggregate technologies and their use; pumice production- consumption and reserves in the world and Turkey, and the literature are examined. In the Fourth Chapter; the materials used in the experiments and their characteristics, mixtures, tests and results are presented in tabular form and also in graphical comparisons.