Evaluating the Durability of Green Cement Mortar Using Ultrasonic Pulse Velocity

Abstract

Various experimental studies have highlighted the negative consequences of Portland cement on health and the environment, such as toxic emissions and alkaline sewage. The development of environmentally acceptable substitutes for cement is thus one of the objectives of current investigations. The proposed environmental alternatives to cement, nevertheless, might have detrimental impacts on the concrete’s characteristics. This investigation intends to study the suitability as alternatives to cement in cement mortar, using industrial wastes like silica fume and cement kiln dust. As a replacement for cement, the cement mortars developed in this research continue from 0% to 60% silica fume and cement kiln dust. Ultrasonic pulse velocity tests at 1 to 4 weeks of age were conducted on hardened specimens. The findings showed that a low reduction in the pulse velocity resulted from high proportions of silica fume and cement kiln dust replacements, whereas an improvement in the characteristics of the mortars with low replacement ratios. Using low kiln dust and silica fume of 20 to 40%, the durability of mortars may increase.

Effect of low-calcium fly ash inclusion on long-term mechanical properties and durability of ground granulated blast furnace slag-based cement-free mortars

“…The reduction of the total charge pass could be attributed to the additional formation of hydration products which reduced porosity in the samples. 49 The total charge passed in all the CFM samples was in the range of 836–1503 C while the cement-based mortar sample (C100) had a total charge passed from 1270 to 1838 C. It indicates that the C100 and all the CFM samples exhibited low chloride ion penetrability as indicated by ASTM C1202. When compared with the C100 sample, the CFM samples had a lower total charge passed regardless of curing age, demonstrating the effectiveness of low-calcium FA at a high replacement level in the CFM samples based on GGBFS.…”

“…This tendency was also confirmed in several existing studies. 48,49 This may be explained that the curing age positively affects the gain and growth of hydration products, decreasing interior voids and increasing the density of such samples. 49 As a result, the UPV value at 120 days was 1.03–1.07 as much as that at 28 days of the mortar samples.…”

“…48,49 This may be explained that the curing age positively affects the gain and growth of hydration products, decreasing interior voids and increasing the density of such samples. 49 As a result, the UPV value at 120 days was 1.03-1.07 as much as that at 28 days of the mortar samples. The UPV value of the CFM samples was in the range of 3899-4437 m/s while that of the control sample (C100) was from 3797 to 3945 m/s which was higher than 3660 m/s, indicating that the control samples had good quality as indicated by Ullah et al 50 The UPV value of the CFM samples was higher than that of the control sample (C100), irrespective of curing age.…”