Self-consolidating concrete (SCC) has been used extensively in the construction industry because of its advanced characteristics of a highly flowable mixture and the ability to be consolidated under its own weight. One of the main challenges is the high content of OPC used in the production process. This research focuses on developing sustainable, high-strength self-consolidating concrete (SCC) by incorporating high levels of supplementary cementitious materials. The overarching purpose of this study is to replace OPC partially by up to 71% by using fly ash, GGBS, and microsilica to produce high-strength and durable SCC. Two groups of mixtures were designed to replace OPC. The first group contained 14%, 23.4%, and 32.77% fly ash and 6.4% microsilica. The second group contained 32.77%, 46.81%, and 65.5% GGBS and 6.4% microsilica. The fresh properties were investigated using the slump, V-funnel, L-box, and J-ring tests. The hardened properties were assessed using a compressive strength test, while water permeability, water absorption, and rapid chloride penetration tests were used to evaluate the durability. The innovation of this experimental work was introducing SCC with an unconventional mixture that can achieve highly durable and high-strength concrete. The results showed the feasibility of SCC by incorporating high volumes of fly ash and GGBS without compromising compressive strength and durability.

Anti-washout concrete (AWC) is engineered for underwater constructions, with resistance to dispersion achieved through the use of anti-washout admixtures (AWAs). This study experimentally investigated the design of sustainable anti-washout concrete mixtures containing a high content of by-product waste materials. The study aims to evaluate sustainable underwater concrete mixtures with high supplementary cementitious materials content, analyze the influence of AWA on compressive strength, and assess the compatibility of anti-washout admixture with both SCMs and superplasticizers. However, the interaction of AWA with a high content of ground granulated blast furnace slag (GGBS) and microsilica in underwater concrete has not been previously investigated. Two groups of concrete mixtures were developed: the first group consisted of two sustainable mixtures, with and without AWA, containing 52.15% ordinary Portland cement (OPC), 43.5% GGBS, and 4.35% micro silica. The second group consisted of two conventional mixtures: one with 100% OPC and the other with 100% OPC plus AWA. Fresh properties, such as slump flow, viscosity (measured by the V-funnel), and air content, were evaluated. Compressive strength was measured to assess mechanical performance. Durability was investigated using four tests: rapid chloride penetration tests (RCPT), water penetration, water absorption, and initial surface absorption tests (ISAT). An anti-washout test was conducted to determine the effectiveness of AWC in minimizing the washout of cement particles. The mixture design introduces an innovative approach to utilizing high levels of SCMs for producing high-strength, durable, and sustainable AWC. The durability results showed that the ISAT test was ineffective for evaluating concrete performance underwater. This research contributes to understanding the effects of AWAs and their compatibility with superplasticizers and SCMs. AWA forms a thixotropic gel that protects cement particles from washout and is highly compatible with superplasticizers.