Experimental investigation of mix design for high-strength alkali-activated slag concrete

The Effect of Mixture Proportion on the Performance of Alkali-Activated Slag Concrete Subjected to Sulfuric Acid Attack

“…The main reason is that when the A/S ratio increases from 0.4 to 0.6, the amount of binder is reduced. Thus, there is not enough binder to cover aggregates and form an integrated structure which was also reported in [ 16 , 47 , 48 ].…”

“…Alkaline activation of different industrial byproducts such as slag, fly ash, and natural minerals produce these alternative binders that possess cementitious properties [ 15 ]. Activation of slag with an alkaline solution such as sodium silicate (Na 2 SiO 3 ) and sodium hydroxide (NaOH) can produce alkali-activated slag concrete (AASC) that has been reported to have superior acid resistance performance [ 16 , 17 ]. Properly designed AASC mortars showed sulfuric acid resistance, but the addition of GGBFS led to the formation of expansive calcium sulfate resulting in a decrease in acid resistance of AASC samples [ 18 ].…”

“…The type of ion in alkali activator [ 21 ], the application of nano-silica or micro silica modifications that improve the microstructure of the matrix [ 22 ], and the chemical composition of aluminum silica materials such as slag, fly ash, and micro-silica [ 4 , 17 , 23 , 24 ] are some of the underlying factors that can influence the acid resistance of AASC. The most effective activator used in development of high-strength AASC is Na 2 SiO 3 solution [ 16 , 25 , 26 ]. Previous research efforts confirmed that using Na 2 SiO 3 with proper Na 2 O content and silica modulus creates high-strength AASC [ 16 , 25 , 26 ].…”

“…The most effective activator used in development of high-strength AASC is Na 2 SiO 3 solution [ 16 , 25 , 26 ]. Previous research efforts confirmed that using Na 2 SiO 3 with proper Na 2 O content and silica modulus creates high-strength AASC [ 16 , 25 , 26 ]. The predominance of CSH and the volume of pores in the size of the mesopores range characterize the blast furnace slag concrete activated with sodium silicate.…”

“…Hence, the development of high-strength concrete using Na 2 SiO 3 and NaOH is recommended [ 27 , 28 ]. AASC is reported to achieve a compressive strength of more than 80 MPa at 28 days [ 16 , 26 , 29 ]. Although the application of alkaline solutions contributes to CO 2 emissions [ 30 , 31 , 32 ], the AASC emission level could be significantly lower than OPC concrete if formulated properly [ 33 ].…”