Experimental Study On Properties Of Green Concrete Containing Wood Ash,Silica Fume,Fly Ash,and Plastic Waste

The productions of wood ash,silica fume,fly ash and plastic waste are increasing daily,which makes it crucial to find a sustainable use for these wastes.We attempted to utilize a significant amount of these wastes in the manufacture of normal cement concrete(NCC),self-compacting concrete(SCC)and lightweight self-compacting concrete(LWSCC).Wood ash,silica fume and fly ash were used to partially replace cement while waste plastic powder and waste plastic coarse aggregate were used as partial replacements for fine aggregate and coarse aggregate,respectively.Thus,the resulting concretes are green product with significant environmental benefits,as they minimize the use of cement and natural resources such as sand and stone.There are twenty concrete mix design cases with various wood ash,fly ash,silica fume and waste plastic ratios.Numerous flow tests,including the slump flow test,the J-Ring test,the L-Box test and the V-Funnel test,were conducted to determine the flow characteristics of the above-mentioned concrete.Compressive strength,splitting tensile strength and flexural strength tests were performed on all designed mixes to determine the mechanical properties.The use of silica fumes as a cement substitute in the production of concrete produced beneficial results.Silica fume mass fraction was adopted as 0%,5%10%and15%for normal cement concrete.All strengths for normal cement concrete including CS,STS and FS increase when silica fume mass fraction increase from 0%to 10%while they all decrease when silica fume mass fraction increases from 10%to 15%.The maximum strength was obtained by substituting 10%SF for cement.Fly ash mass fraction was adopted as 0%,10%,20%and 30%for normal cement concrete.All strengths for normal cement concrete including compressive strength,splitting tensile strength and flexural strength decrease when fly ash mass fraction increases from 0%to 30%.Wood ash mass fraction was adopted as 0%,5%,10%and 15%for normal cement concrete.All strengths for normal cement concrete including CS,STS and FS decrease when wood ash mass fraction increases from 0%to 15%.The strength reduction is relatively small and acceptable when wood ash and fly ash are used as a partial replacement for cement.For self-compacting concrete cases,wood ash mass fraction was also adopted as 0%,5%,10%and 15%while silica fume mass fraction and fly ash mass fraction was adopted as 10%and 20%,respectively.All strengths for self-compacting concrete including CS,STS and FS decrease when wood ash mass fraction increases from 0%to 15%.The strength reduction is relatively small and acceptable.Meanwhile,the addition of wood ash to SCC reduces the flowing properties.However,all of the flowing properties meet EFNARC guidelines,and no visible blocking was observed during the flow characteristics test.For lightweight self-compacting concrete,plastic powder mass fraction adopted as25%,40%,55%,70%,85%and 100%while wood ash mass fraction,silica fume mass fraction,fly ash mass fraction and plastic aggregate mass fraction was adopted as 5%,10%,20%and 30%,respectively.The addition of plastic powder reduces their flowing properties,mechanical properties and density.However,all results conform to EFNARC guidelines,with no visible blocking observed during the flow characteristics tests.The density of all LWSC mixtures was determined to be less than 1950 kg/m~3,indicating that the addition of plastic powder and plastic coarse aggregate lightened the concrete.The strength reduction is relatively small and acceptable.The uses of wood ash,silica fumes,fly ash and waste plastic have good environmental protection significances.