Engineering characteristics of modified roller- compacted concrete pavement / Mohammad Hashemi

Mohammad , Hashemi (2019) Engineering characteristics of modified roller- compacted concrete pavement / Mohammad Hashemi. PhD thesis, Universiti Malaya.

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Abstract

In order to investigate new characteristics of roller-compacted concrete pavement (RCCP), the first part of the study dealt with the analysis of fresh and hardened properties of RCCP subjected to applying different coarse to fine aggregate (C/F) ratio, the use of low fines content sand and study on optimum moisture content in RCCP production. Test results showed that the most suitable C/F ratio for RCCP may appear to be from 1.2 to 1.4. The use of low fines content sand in RCCP for both cement contents of 12% and 15% did not significantly affect the mechanical properties of RCCP at all ages. In addition, the study on optimum moisture content of RCCP concluded that a workable, high-strength, and durable RCCP can be made with a moisture content less than the optimum moisture content, which is corresponding to the maximum dry density. In the second part of the study, a comprehensive numerical comparison between normal vibrated concrete (NVC) and RCCP was presented. Test results showed that mechanical properties of RCCP was higher than that of NVC. Durability performance of RCCP is also better than NVC at the same mix proportions. The effect of using different amount of superplasticizer on the fresh and hardened properties of two RCCPs with cement contents of 12% and 15% showed that with the use of superplasticizer, the 28-day compressive strength for RCCP containing 12% and 15% cement increased by 9% and 14%, respectively. Also, Ultrasonic pulse velocity, field emission scanning electron microscope and thermal conductivity test results showed that the use of superplasticizer in RCCP may lead to denser structure. Finally, the results of experimental program showed that the incorporation of lightweight expanded clay aggregate (LECA) by 50% as coarse aggregate in RCCPs with 12% and 15% cement contents can cause 15% and 13% lesser density, 9% and 13% higher workability, respectively, with suitable results in terms of hardened properties and durability.

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