Investigation of Workability and Compressive Strength of Wood Ash Cement Concrete Containing Nanosilica

Abstract

Studies have revealed that wood ash cement concrete just like other pozzolanic cement concrete has lower early strength compared to plain cement concrete. Nanoparticles have been found to improve the early strength of concrete due to its small size and large surface area. This paper reports the findings on influence of nanosilica on the workability and compressive strength of wood ash cement concrete. Wood ash was obtained as a waste product from Ladoke Akintola University of Technology (LAUTECH) bread bakery, Ogbomoso. Biological synthesis of nanosilica using kola pod extract and silica precursor (1:5) was conducted at Nanotechnology research group laboratory at LAUTECH. The chemical composition, specific gravity and grading of wood ash, fine and coarse aggregate used were determined. Concrete with 10% wood ash replacement for cement was produced using 1:2:4 mix proportion and water to binder ratio of 0.5. Nanosilica was added at 0.5, 1.0, 1.5 and 2.0% levels. Concrete with no wood ash and nanosilica served as the control. Workability and compressive strength of the plain and composite concrete were determined. The results showed that concrete workability was enhanced with introduction of nanosilica. The compressive strength also increased with the addition of nanosilica. Maximum compressive strength of 27.53MPa was achieved at 90 days with 1.5% nanosilica addition. It was concluded that nanosilica enhanced workability and improved both early and later strength development in wood ash concrete with 1.5% as the optimum addition.

Effect of nano-materials on mechanical properties of cement and concrete

“…However, the compressive strength for 15% of fly ash in concrete at 90 days of age has increased slightly compared to the control sample. Rahim et al investigated the effect of adding nanosilica in concrete containing cement with wood ash on its compressive strength [6] . It contains a sample containing 2% nanosilica in the presence of wood ash (0.WA 10 NS 2 ).…”

“…Addition of 1, 3 and 5% NanoSiO 2 and NanoTiO 2 to ordinary concrete indicates a 12% increase in compressive strength in a sample containing 1% nano-silica and an 18% increase in the sample containing 1% nanotitania [4,5] . In another study Zr, Fe, Ti and Al nano-oxides were used in the amount of 1.5% by weight of cementitious materials in super-reinforced concrete and the best improvement in compressive strength of 55% was reported in samples containing nano-alumina [6] Addition of nano-silica and nano-alumina by 0.5 to 2% and curing in both water and lime water showed that in both cases nano-silica had a better effect than nano-alumina and also the results of the treated samples. In lime water, they showed a better improvement than 7 [7] .…”

“…The use of silica and titanium nanoparticles and PP (polypropylene) fibers in concrete showed a 31 and 18% improvement in chloride penetration resistance in samples containing 1% titanium nano dioxide and 1% nanosilica, and PP fibers had a negative effect on resistance to chloride penetration; also in this study, samples containing low percentages of nanomaterials) showed 1% (better improvement than samples containing higher percentages) 3 and 5% (against chloride penetration [4] . Nanoparticles of NZrO 2 , NFe 3 O 4 , NTiO 2 and NAl 2 O 3 were used in 1.5% HPC concrete, 80% improved in water absorption of samples containing NFe 3 O 4 and NTiO 2 , and 70% improved in the penetration of NZrO 2 chloride with NAl 2 O 3 (70%) [6] . In a study on porous concrete, nano-silica with values of 1, 3, 5 and 7% and micro-silica with 3, 5 and 8% were used separately.…”

Characteristics of Wood Ash Cement Mortar Incorporating Green-Synthesized Nano-TiO2

“…As reported by Stenfanidou and Papayianni (2012), nanoparticles act as fillers in empty spaces and as crystallization centres of hydrated products, thereby increasing the rate of hydration and strength development. Nanomaterials that are commonly used in concrete and mortar are nano-SiO 2 , nano-TiO 2 , nano-Al 2 O 3 , nano-Fe 2 O 3 , nano-ZnO and carbon nano-tubes (Mohamed 2016;Heikal 2013;Sharobim and Mohammedin 2013;Ren 2018;Raheem and Ikotun 2019). Several of the available studies had focused on the effect of nano-SiO 2 on properties of cement pastes, mortar and concrete.…”