Comparative Experimental Study of Sustainable Reinforced Portland Cement Concrete and Geopolymer Concrete Beams Using Rice Husk Ash

Abstract

The ordinary Portland cement (PC) manufacturing process emits toxic carbon dioxide into the environment. Minimizing cement consumption in the construction industry is a major scholarly priority. This paper studies the comparison of reinforced Portland cement concrete and geopolymer concrete beams, in which rice husk ash (RHA) is used as a partial replacement for cement. The study aims to determine the optimum mix proportion of Portland cement concrete with RHA (PC-RHA) and geopolymer concrete with RHA (GC-RHA) for compressive strength that meets the requirements for normal strength concrete of 18, 25, and 32 MPa and compares to ones of the control PC without RHA. Then, the load behaviors and the failure modes of the reinforced PCC beam and reinforced GC beam using RHA as partially PC (PC-RHA beam and GC-RHA beam) were investigated. The obtained experimental load capabilities were also compared to ones predicted by the equation for designing reinforced concrete beams developed by ACI Committee 318. According to the test results, the compressive strength of the PC-RHA and GC-RHA decreased when there was a higher proportion of RHA replacement in the concrete. In terms of the structural behavior, all the PCC, PC-RHA, and GC-RHA beam curves are bilinear up to the first crack load and before the yield load, then become nonlinear after the yield load of the beam specimens. The maximum crack width of the GC-RHA beam was less than that of the PC-RHA beam. Furthermore, the GC-RHA beam was more ductile than the PC-RHA beam. Finally, the ACI equation provides reliable predictions with a margin of error of 4 to 7%. This concludes that the experimental load capabilities of the PC-RHA beam and GC-RHA beam were consistent with the ACI design equation.

Flexural Behavior of Steel and FRP-Reinforced Geopolymer Concrete Beams : Numerical Modeling and Analytical Study

“…Where: M u is the flexural capacity of the normal section of the tested beam, f c is the concrete compressive strength (MPa), f y is the tensile strength for steel (MPa), The parameters of each tested beam are substituted into the above equation to calculate the ultimate moment capacity Mu. The calculated and experimental results are listed in Table 5, together with results obtained by Thumrongvut et al [27]. It is observed that the predicted values of the beam's ultimate flexural capacity Mu are close to the experimental values, therefore the presented formula can be effectively applied to determine the ultimate capacity of GC flexural elements.…”

Safety and Effect of Fly Ash Content on Mechanical Properties and Microstructure of Green Low-Carbon Concrete

“…Large amounts of CO 2 emission leads to the greenhouse effect and aggravates global warming. A large portion of the waste produced in the manufacturing process is dumped and disposed of in landfills, damaging the soil and causing environmental pollution [4]. Since the sustainable development model of the social economy has been proposed, the protection of the environment and ecology is required in the production, use, maintenance, and reuse of concrete [5].…”

Review of Recent Developments Regarding the Durability Performance of Eco-Friendly Geopolymer Concrete

“…Both FA and GGBS undergo suitable treatment processes before being utilized as geopolymer materials in construction projects [47]. In addition, other waste materials were used to produce GPC, such as rice husk ash [63], waste glass [64], palm oil fuel ash [65], ceramic waste [66], bagasse ash [39], illitic clay [67], Moroccan clays [68], clay minerals [69], and smectite clay [70], silica fume [65], waste clay brick [71], waste bricks powder [72], sewage sludge ash [73], and basalt powder [74]. Alkali-activated materials can generally be divided into two groups: (a) the high calcium system, where GGBS is a representative precursor and results in the formation of a C-A-S-H type gel as the main reaction product; and (b) the low calcium system, where class F FA and metakaolin are representative raw materials and produce N-A-S-H type gels within a three-dimensional network as the main reaction product [75].…”