Microstructure and Mechanical Property Evaluation of Dune Sand Reactive Powder Concrete Subjected to Hot Air Curing

Abstract

The use of different sustainable materials in the manufacture of ultra-high-performance concrete (UHPC) is becoming increasingly common due to the unabating concerns over climate change and sustainability in the construction sector. Reactive powder concrete (RPC) is an UHPC in which traditional coarse aggregates are replaced by fine aggregates. The main purpose of this research is to produce RPC using dune sand and to study its microstructure and mechanical properties under different curing conditions of water curing and hot air curing. The effects of these factors are studied over a long-term period of 90 days. Quartz sand is completely replaced by a blend of crushed and dune sand, and cement is partially replaced by using binary blends of ground granulated blast furnace slag (GGBS) and fly ash (FA), which are used alongside silica fume (SF) to make a ternary supplementary binder system. Microstructural analysis is conducted using scanning electron microscopy (SEM), and engineering properties like compressive strength and flexural strength are studied to evaluate the performance of dune sand RPC. Overall, the results affirm that the production of UHPC is possible with the use of dune sand. The compressive strength of all mixes exceeded 120 MPa after 12 h only of hot air curing (HAC). The SEM results revealed the dense microstructure of RPC. However, goethite-like structures (corrosion products) were spotted at 90 days for all HAC specimens. Additionally, the use of FA accelerated the formation of such products as compared to GGBS. The effect of these products was insignificant from a mechanical point of view. However, additional research is required to determine their effect on the durability of RPC.

Compressive Strength Development of Dune Sand Reactive Powder Concrete (RPC) Under Different Curing Conditions

“…The strength for the control mix increased only up to 24 hours and then started to decrease while for the other mixes the strength continued to increase until 48 hours. For the control mix, the decrease observed after 24 hours, may denote that there is an optimal crystallization limit which when exceeded, crystallinity becomes undesirable, and the strength decreases [17]. Such behavior has previously been reported in studies that investigated the effect of autoclave curing on RPC strength [18], [19].…”

Evaluation of Workability and Structuration Rate of Locally Developed 3D Printing Concrete Using Conventional Methods

“…Moreover, the SP dosage used to adjust the extrudability of the D-GB mix was lower than that of the D-CM mix. This was expected as, unlike cement, only a few water molecules get absorbed by the GB particles due to their dense surface, thus enhancing its workability [ 3 , 39 ].…”

Experimental and Statistical Study of Flexural Strength in Ternary Blended High-Performance Concrete using Alcofine

“…As the construction industry strives to reduce its carbon footprint and optimize resource utilization, the exploration of alternative materials and mix designs becomes essential. Alccofine, a byproduct of industrial processes, offers a sustainable solution by utilizing waste materials and enhancing the performance of concrete , 01012 (2024) E3S Web of Conferences https://doi.org/10.1051/e3sconf/202449101012 491 ICECS'24 [13]. The study aims to contribute to the body of knowledge surrounding ternary blended concrete, providing insights into the flexural strength characteristics and establishing a comparative framework against traditional concrete [14].…”