Effects of waste glass and waste foundry sand additions on reclaimed tiles containing sewage sludge ash

The Use of Modal Analysis in Addition Percentage Differentiation, and Mechanical Properties of Ordinary Concretes with the Addition of Fly Ash from Sewage Sludge

Production cost reduction and constraints on natural resources cause the use of waste materials as substitutes of traditional raw materials to become increasingly important. The dynamic development of sewerage systems and sewage treatment plants leads to increases in the produced sewage sludge. According to the Waste Law, municipal sewage sludge can be used if it is properly stabilized. This process results in significant quantities of fly ash that must be utilized. This paper presents investigation results of partial cement replacement influence by the fly ash from sewage sludge on concrete parameters. The results confirm the possibility of fly ash waste applications as a cement substitute in concrete manufacturing. In the later parts of the publication, a pilot study was conducted using the modal analysis methodology and aimed at checking the hypothesis of whether vibration methods can be used in the assessment of the amount of the admixture used in concrete and the effect it has on concrete properties. This is the first time that vibration tests have been used to determine the diversity of the concrete mix composition and to distinguish the percentage of ash added. There are no studies using modal analysis to distinguish the composition of a concrete mix in the scientific literature. The article shows that the vibration test results show the differentiation of concrete composition and can be further improved as a method for determining the composition of mixtures and for distinguishing their mechanical properties. These are only pilot studies, which, in order to develop the target cognitive inference, should be performed in the future on a significantly enlarged number of the studied samples.

Fly Ash from Thermal Conversion of Sludge as a Cement Substitute in Concrete Manufacturing

Striving for reduction of production costs and constraints on natural resources cause the use of waste materials as substitutes of traditional raw materials to become increasingly important. Dynamic development of sewerage systems and sewage treatment plants observed over the recent years leads to increase of mass of the produced sewage sludge. According to the Waste Law, the municipal sewage sludge can be used if it is properly stabilized, e.g., through thermal processing. This process results in significant quantities of fly ash which must be properly utilized. The paper presents results of investigations of influence of partial replacement of cement by the fly ash from sewage sludge on concrete parameters. It was designed as a C20/25 class concrete mix, based on the Portland cement CEM I 42.5R with various ash content. Physical and chemical properties of the ash as well as frost resistance and the compressive strength of the concrete after 28, 56 and 365 days of curing were investigated. The obtained results of investigations confirm the possibility of application of fly ash wastes as a cement substitute in the concrete manufacturing. If a predefined quantity of cement is replaced by the fly ash, then one can obtain cement composite with good strength parameters.