This study aims to evaluate the physical properties of non-sintering cement (NSC) concrete by adding phosphogypsum (PG) and waste lime (WL) to granulated blast furnace slag (GBFS) as sulfate and alkali activators. The study measured changes in the physical properties of fresh concrete using NSC, and the compressive, flexural and tensile strength of the hardened concrete for 360 days. In the results of the experiment, concrete using NSC was superior to that using Ordinary Portland Cement (OPC) or blast-furnace slag cement (BSC) in terms of fluidity and hydration heat characteristics. In addition, the early strength of concrete using NSC was relatively low at around 85% of the strength of concrete using OPC on day 3, but this was reversed from day 7 and the difference between OPC and BSC grew steadily larger over time until day 360. The strength of concrete using NSC develops continuously because the GBFS component eluting as GBFS is activated by PG and WL, and due to their reaction, ettringite, C-S-H gel, etc. are generated steadily for a long time, and there is no transition zone in the interface between the aggregate and paste because Ca (OH) 2 is hardly generated from the hydration process, and as a result, interfacial adhesion is reinforced with aging.
Carbonation has been considered as a deterioration factor in concrete because it reduces the pH of concrete from between 12.6 and 13.5 to about 9. However, carbonation can have some positive consequences. Because CaCO 3 occupies a greater volume than Ca(OH) 2 , which it replaces, the porosity of carbonated concrete decreases. On the other hand, carbonation turns bound chloride into free chloride. The results verify that carbonation has some beneficial effects by enhancing compressive strength and volume safety and reducing permeability and chloride ion penetration. In general, carbonation enhances concrete performance.
This study investigates the effects of the emulsifier content and monomer ratio on the typical properties of the polymer-modified mortars with methyl-methacrylate-butyl-acrylate (MMA/BA) and methyl-methacrylate-ethyl-acrylate (MMA/EA) latexes and obtains basic data necessary to develop appropriate latexes for cement modifiers. The polymer-modified mortars using the MMA/ BA and MMA/EA latexes polymerized with emulsifier contents and at various monomer ratios are prepared for different polymer-cement ratios, and tested to obtain the particle size of the polymer latexes, the glass transition temperature of the polymer film, air contents, water-cement ratios, flexural and compressive strengths, water absorption, and chloride ion penetration. From the test results, the polymermodified mortars using MMA/BA and MMA/EA latexes with the mix proportions of synthesis having emulsifier contents of 5-6% and monomer ratios of 50 : 50 to 60 : 40 for the appropriate mix proportions can be recommended for practical applications. The basic properties of the polymermodified mortars are more affected by the polymer-cement ratio rather than the monomer ratio and emulsifier content, and are improved over unmodified mortar.
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