Browsing by Author "Msambichaka, J, J & Mboya, H, A,"

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    Evaluation of Pumice Lightweight Concrete as Material for Thin-Shell Structures
    (Mbeya University of Science and Technology Journal of Research and Development (MJRD), 2022-06-07) Shiganza, O,J; Msambichaka, J, J & Mboya, H, A,
    The properties of concrete depend on cement content, water-cement ratio, and the types and mechanical properties of aggregates used. The strength of pumice lightweight concrete is governed by the strength of mortar and pumice aggregates in the mixture. The properties of fresh and hardened pumice lightweight concrete, such as workability, density, compressive and flexural strengths, are among the parameters required in the design of thin shell structures. These parameters, which involved two batches, were dealt with in this research, and the results are in line with American Concrete Institute 318 requirements. Absolute volume methods as stipulated by American Concrete Institute Committee 211.2-98 were used for selecting and adjusting proportions for lightweight concrete. The two hand mixed batches were used to evaluate the concrete. As a result, the excessive pumice lightweight aggregates content of batch No.1 proved to have poor strength. The reduced pumice lightweight aggregates content of batch No. 2 established satisfactory strength results. The average specific gravity and water absorption of pumice lightweight aggregates were 1.1 and 98.3%, respectively. Pumice lightweight concrete achieved a compressive strength of 23.6 N/mm2 measured at 28 days as compared with American Concrete Institute 318, which requires at least 17 N/mm2. Pumice lightweight concrete satisfies the requirements of the code for the design of thin shell structures. Therefore, pumice lightweight aggregates can be used as a partial replacement of normal weight aggregates for the design and construction of thin shell structures up to 18.75%.