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Reactive powder concrete (RPC) consuming a large amount of Portland cement results in high cost. To reduce the cement used in RPC, the silica fume and ground granulated blast-furnace slag have been used as cement replacement. However, those materials are not available in Aceh Province - Indonesia. The objective of this research is to propose the mix design of RPC composed of locally available materials. In this paper, the mix design of RPC using calcined diatomaceous earth powder as partial cement replacement is presented. The iron ore powder was used as filler, and river sand with a diameter of less than 1 mm was used as aggregate. To maintain the workability of concrete, superplasticizer was added. The bulk density, specific gravity as well as particle size distribution of Portland cement, diatomaceous earth powder, iron ore powder and river size were tested. The modified Andreasen and Andersen model was utilized. The mix proportion of materials was determined using an optimization algorithm based on the least-squares method. Furthermore, all materials were mixed to produce RPC; and then the properties of fresh and hardened concrete i.e. workability, air content, compressive strength, splitting tensile strength, and flexural strength, were tested. The relative slump flow decreases with the increase of diatomaceous earth binder. The RPC with diatomaceous earth powder has a lower 7 days compressive strength but high flexural strength and splitting tensile strength.

In this study, the effects of calcined diatomaceous earth (CDE), polypropylene fiber (PF), and glass fiber (GF) on the mechanical properties of ultra-high-performance fiber-reinforced concrete (UHPFRC) were observed, and a total of 33 UHPFRC mixtures, consisting of 3 mixtures without fiber, 15 mixtures with PF, and 15 mixtures with GF were prepared. Subsequently, the fresh concrete mixtures were tested for flow, while the hardened concrete specimen’s mechanical properties were analyzed. These tests include compression, splitting tensile, and flexural tests. The test results showed that the use of 5 and 10% CDE as a binder for cement replacement improved the compressive strength, splitting tensile strength, and flexural strength of the UHPFRC. Furthermore, the addition of PF and GF contents of up to 1% of the concrete volume increased the compressive strength of the UHPFRC, while their contents of up to 1.5% improved their splitting tensile strength and flexural strength. It is also important to note that the workability of the UHPFRC reduced as the fiber and CDE contents increased. Finally, based on the experimental data tested in this study, the relationship between splitting tensile strength, flexural strength, and compressive strength of the UHPFRC containing PF and GF were proposed. Moreover, the reduction in flow value, which is a function of the volumetric content of both PF and GF, with the CDE contents was also proposed.

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This study aimed to determine the mechanical properties and absorption of high-strength fiber-reinforced concrete (HSFRC), using sustainable natural fibers. In this analysis, two types of fibers were used, namely, ramie and abaca. Two different HSFRC mixtures were also designed, where one composition emphasized ordinary Portland cement (OPC) as a binder, and the other prioritizing calcined diatomaceous earth (CDE) as a mineral additive to replace 10% weight of OPC. Furthermore, ramie and abaca fibers were separately added to the mixtures at three different volumetric contents. Based on the results, the addition of these fibers in the concrete mixtures improved the mechanical properties of HSFRC. The improvements of compressive strength, splitting tensile strength, and flexural strength, due to the addition of ramie fiber were 18%, 17.3%, and 31.8%, respectively, while those for the addition of abaca fiber were 11.8%, 17.2%, and 38.1%, respectively. This indicated that the fibers were capable of being used as alternative materials for sustainable concrete production. The effects of ramie and abaca fibers on the absorption of HSFRC were also not significant, and their presence for the same amount of superplasticizer reduced the flow speed of fresh reinforced concrete mixtures.