Properties and Microstructure of Cement Paste Including Recycled Concrete Powder

2017

APP

Self Cite

Abstract. Recycled concrete powder (RCP) mostly consisting of cement paste could be reused as partial cement replacement. The aim of this paper is to compare hydration and mechanical properties of RCP and two types of silica sand powder (SSP). Comparison of those materials combined with cement can highlight the binder properties of recycled concrete powder. Using of two types of SSP also show an influence of their fines on hydration process and mechanical properties. Particle size analysis and calorimetric measurement were carried out and mechanical properties such as bulk density, dynamic Young's modulus and compression strength were examine. Calorimetric measurement proves the presence of exposed non-hydrated particles in RCP that can react again. However lower density of old cement paste in RCP overweight the mentioned potential of RCP and mechanical properties are decreasing compared with reference cement paste and cement paste SSP.

Section: Introductionmentioning

confidence: 99%

Hydration Process and Mechanical Properties of Cement Paste With Recycled Concrete Powder and Silica Sand Powder

Topič

2017

APP

Self Cite

“…A set of instruments and devices was used to measure natural frequency of all samples in longitudinal, transverse [8,9]. The measurement of the dynamic modulus of elasticity and the dynamic shear modulus was taken from the work of J. Topič [10]. The flexural strength was measured at the end of the 28 days period by using three-point bending test on samples measuring 40 × 40 × 160 mm.…”

Section: Measurement Methodsmentioning

confidence: 99%

Mechanical and Chemical Activation of Blast Furnace Slag and Its Influence on the Mechanical Properties of the Resulting Cement Paste

Horych

Tesárek

2021

APP

The usage of waste materials is a very important global topic. The large amount of waste everywhere in the world needs to be processed or disposed. Landfilling is not an option anymore, because of European legislation and restrictions. A lot of studies are trying to develop new options or possibilities of using waste materials. This research is trying to find a way to process blast furnace slag. A high-speed mill was used for the mechanical activation. Chemical activation was used as the next step of activation. There are many materials that could be used, but in this study we used slaked lime and water-glass. Slaked lime had a positive effect on mechanical properties. Samples had higher compressive strength but the effect was limited only for 5 wt. %. Another used material was water-glass, but in this case, there was a significant negative effect. Compressive strength and flexural strength were significantly reduced.

“…The greater interest in this material is due to the large use of concrete in construction. The observation of the influence on mechanical properties in this area can be found in many researches by J. Topič, P. Tesárek et al [3], [4], [5].…”

Section: Introductionmentioning

confidence: 93%

The Influence of the Use of Recycled Gypsum on the Properties of Gypsum Products in Labor Conditions

Sekavová

Herrmann

et al. 2020

APP

The article presents the first results from research, which is deal with recycling of plaster boards and use of the resulting material. The research is carried out within the project MPO Trio c. FV30359 “Recyklace sádrokartonových desek a nová materiálová využití s pridanou hodnotou – GIPSRec”. The plasterboards are produced of stucco, which is calcinated of Flue Gas Desulfurization Gypsum (FGD Gypsum). There is possibility to replace a part of this stucco with recycled material. There is opportunity for saving costs for production. The question how this utilization can change the properties of the products is very important and it is necessary to find the possible improvement or deterioration. This is the objective of this research. The effect on properties was monitored on the samples which was prepared of only pure stucco and of stucco with part of recycled material. There was observed water ratio (splash test), setting times, volume changes, flexural strength, compressive strength and elasticity module.