Ultrasonic Evaluation of Cement-Based Building Materials Modified Using Marble Powder Sourced from Industrial Wastes

This paper presents an experimental study on the assessment of the cement-based materials properties made with marble powder (MP) at different replacement ratios (0%, 5%, 10%, and 15%) of cement by using the ultrasonic pulse velocity (UPV) test. The used MP has a Blaine fineness similar to that of Portland cement. The physical and the chemical characteristics of Portland cement and MP were determined. To determine the UPV values, cubic specimens (50 × 50 × 50 mm3) of cement paste and mortar were prepared and cured either in air at a temperature equal to 22 ± 2 °C and relative humidity equal to 20 ± 1%, or in water at a temperature equal to 20 ± 1 °C. The experimental tests including the UPV, the compressive strength (fcd), and the apparent density (ϒad) were conducted at 3, 7, 28, and 65 days, the relationship between each of these parameters were presented. Additionally, economic performance of cement and waste MP used in this study was performed. The results show that the use of MP as partial replacement of cement causes a decrease in the compressive strength and apparent density in both curing conditions. In addition, the results show a good relationship between the destructive test and non-destructive test adopted by UPV

Effectiveness of the Use of Polymers in High-Performance Concrete Containing Silica Fume

The incorporation of polycarboxylate ether superplasticizer (PCE)-type polymers and silica fume (SF) in high-performance concretes (HPC) leads to remarkable rheological and mechanical improvements. In the fresh state, PCEs are adsorbed on cement particles and dispersants, promoting the workability of the concrete. Silica fume enables very well-compacted concrete to be obtained, which is characterized by high mechanical parameters in its hardened state. Some PCEs are incompatible with silica fume, which can result in slump loss and poor rheological behavior. The main objective of this research is to study the influence of three types of PCEs, which all have different molecular architectures, on the rheological and mechanical behavior of high-performance concretes containing 10% SF as a partial replacement of cement. The results show that the carboxylic density of PCE has an influence on its compatibility with SF

The Utilization of Waste Marble Dust as a Cement Replacement in Air-Cured Mortar

The aim of this study is to assess the possibility of utilizing waste marble dust (WMD) as a partial cement substitution in air-cured mortar (ACM). Three different levels of cement replacement were analyzed: 5%, 10% and 15% by cement weight. The specimens were manufactured in a local laboratory at an air temperature of 22 ± 2 °C and a humidity equal to 20 ± 1%. The chemical and physical properties of ordinary Portland cement and WMD has been found to be the most crucial parameters. A variety of macroscopic tests, such as apparent density, porosity and compressive strength, were proposed in order to explain the effect of utilizing the WMD on the ACM. To confirm the results of the macroscopic properties, thorough microstructural analysis using scanning electron microscopy (SEM) was performed. The obtained results of this study indicate that replacing cement with WMD affects the physical and mechanical properties of air-cured mortar. The apparent density and compressive strength decrease while the porosity increases