Effects of Alternate Wet and Dry Conditions on the Mechanical and Physical Performance of Limestone Calcined Clay Cement Mortars Immersed in Sodium Sulfate Media

Abstract

Sulfate attack in concrete structures significantly reduces their durability. This article reports the experimental findings on the effects of sodium sulfate on limestone calcined clay cement (LC3) in an alternate wet and dry media. The samples underwent wet–dry conditions of 28 cycles. Two types of LC3 were studied, one made from clay (LC3-CL) and the other made from fired rejected clay bricks (LC3-FR). The composition of each LC3 blend by weight was 50% clinker, 30% calcined clay, 15% limestone, and 5% gypsum. The reference compressive strength was evaluated at 2, 7, and 28 days of age. Then, ordinary Portland cement (OPC) and LC3-CL blends were subjected to alternate wet–dry cycle tests, immersion in a 5% sodium sulfate solution, or in water. For all exposed samples, sorptivity tests and compressive strength were done. The results showed that LC3 blends met the requirements for KS-EAS 18-1:2017 standard, which specifies the composition and conformity criteria for common cements in Kenya. The LC3 blend also had a lower rate of initial absorption compared to OPC. Additionally, LC3 blend also showed good resistance to sodium sulfate when exposed to alternating wetting and drying environment. OPC showed higher compressive strength than LC3 blends for testing ages of 2, 7, and 28 days. However, the LC3 samples utilized in the sodium sulfate attack experiment, which were later tested after 84 days, exhibited higher compressive strengths than OPC tested after the same period.

Effects of Aloe Vera Mucilage as a Superplasticizer on Limestone Calcined Clay Self-Consolidating Concrete Performance

“…LC 3 -50 was successfully introduced by partially substituting limestone and calcined clay for clinker to make pozzolana cement of gypsum (5%), limestone (15%), calcined clay (30%), and clinker (50%) in these studies [12][13][14]. Marangu et al [15] and Odhiambo et al [16] pointed out that the inception of LC 3 binder has benefited the concrete industry by saving on the energy of producing clinker from 1500 °C to about 800 °C of calcining clay as the clinker substitute. By adding suitable admixtures, this new type of green cement could be adapted to the production of SCC.…”

Aloe Vera-Based Concrete Superplasticizer for Enhanced Consolidation with Limestone Calcined Clay Cement

“…LC 3 -50, incorporating gypsum (5%), limestone (15%), calcined clay (30%), and clinker (50%), has demonstrated success in replacing traditional pozzolana cement [12][13][14]. LC 3 's introduction has saved energy in clinker production, as noted by Marangu et al [15] and Odhiambo et al [16]. This innovative cement can be adapted to SCC production with suitable admixtures.…”