Assessment of Optimum CaO Content Range for High Volume FA Based Concrete Considering Durability Properties

Abstract

There have been many studies on the effect of durability and compressive strength on the increase of the mixing rate of admixtures. However, there is no research that can provide a guide on the optimal mixture proportions for maintaining compressive strength and secure durability properties when using local materials. Therefore, the purpose of this article is to assess the durability and engineering performances of concrete based on local fly ash (FA), as well as to derive the optimum CaO content scope for ensuring durability. The results of this study were compared with the results of the previous study of high-volume ground-granulated blast-furnace slag (GGBFS) concrete. To achieve this, tests were carried out by increasing the admixture mixing rate in 10% increments from 0% to 70%. The unit water was set at 175 kg/m3 and the amount of binder was set at 330 kg/m3. It was found that the overall compressive strength of the hardened concrete decreased when the admixture mixing rate increased. In addition, the compressive strength of specimens tended to improve as all the CaO contents of the admixture types increased. When the durability properties were examined, it was found that the relative dynamic elasticity modulus and carbonation depth decreased, and the chloride penetration depth increased as the CaO content increased for both GGBFS and FA. The weight loss rate, however, remained similar. Based on the results of this study, the optimal CaO content that achieved satisfactory engineering and durability properties was found to be between 39% and 48% for FA. The results of this study will be able to offer guidelines for the mixture rates of FA when mixing durable concrete for use in the field. Additionally, these results are expected to be utilized as a basis for determining instructions relating to chemical composition in order to develop binders with improved durability.

An Experimental Assessment of the Water Permeability of Concrete with a Superplasticizer and Admixtures

“…The four different types of concretes used in this work were made with Portland cement (CEM I 32.5 R) complying with the European Standard EN 197-1 [ 29 ], a fossil sand (0–2 mm), and gravel (2–16 mm). One of them represented a conventional concrete mix and three were admixture-modified concrete mixes [ 30 , 31 ]. The aggregate properties and volumes were constant among the mixes, as was the water-to-cement ratio.…”

Carbonation rate of alkali-activated concretes and high-volume SCM concretes: a literature data analysis by RILEM TC 281-CCC

“…The database contains data for 125 GGBS-based AAC [6,8,; 12 FA-or MK-based AAC [8,[32][33][34][35][36]; 18 other AAC [36][37][38][39][40]; and 74 BCC [1,2,6,16,29,[41][42][43][44][45][46][47][48][49][50][51][52]. A plot of the SCM fractions of the binders of the materials (including the compounds dissolved in the activator solution as part of the binder in the calculation) is shown in Fig.…”

Valorization Potential of Polish Laterite Leaching Residues through Alkali Activation

“…-The SiO 2 and Al 2 O 3 content of the GLR were significantly higher (30.8 The PLR had a high content of sulfates (30.6 wt%), which were shown as SO 3 in Table 2 and confirmed by the presence of gypsum (Figure 3). Such sulfate compounds may have caused internal expansion during curing, ageing, and solidification [70]. The presence of gypsum in the precursors and its effect during alkali activation has been investigated in earlier studies, and the results varied.…”