Use of Prefabrication, Construction and Demolition Wastes as an Aggregate in Vibropressed Precast Concrete Blocks Production

The aim of current study was to determine the recycled concrete aggregate (RCA) applicability in the production of concrete mixture for vibropressed concrete blocks. The experiments were focused especially on the crushed waste material from the same concrete elements producing plant.  For this type of precast elements only some finer fractions can be implemented and the “earth-moist” consistency of fresh mixture is required. The series of samples was prepared in which the mixture of natural aggregates was partially or totally substituted by recycled concrete aggregate. The 0/4 RCA fraction, which is usually rejected in ready mix concrete technology, plays a role of 0/2 sand.  The substitution of sand fraction was from 20% to 100% respectively. The substitution of the coarser aggregate fractions by 4/16 RCA was also done. The standard properties of vibropressed elements, such as the degree of densification, the density of material, the compressive and splitting tensile strength and the water absorption capacity according to the relevant standards were determined. The parameters of materials with the natural aggregate substitution by RCA are affected by the ratio of recycled concrete aggregate. In most cases the results do not decline specially from those for reference samples, when only the natural sand (0/2) fraction is substituted by the 0/4 recycled aggregate. As one could expect, as lower the substitution, as better the test results. The partial substitution of natural aggregate by coarser fractions requires experimental verification; over 20% substitution of natural aggregate by 4/8, 8/16 or 0/16 RCA should be excluded

Odpad z płukania kruszywa dolomitowego jako surowiec podstawowy w produkcji ceramiki budowlanej

The amount of waste from washing dolomite aggregates increases continuously. Aggregates are washed to remove clayey pollutants. They consist of a large amount of clay minerals and carbonates. Their properties and amount depends on the type of raw material and type of washing technology. Utilization of waste from washing aggregates is common problem and has not been sought out yet. Their usage as the raw material in ceramics might be environmentally friendly way to utilize them. This paper presents technological properties, phase composition and microstructure analysis of materials made of waste sludge from washing dolomite aggregates. Research was divided into three parts: technological properties analysis, phase composition analysis and microstructure analysis. Samples made of waste dolomite sludge were formed in laboratory clay brick vacuum extruder and fired at 900, 1000 and 1100°C. For final materials, apparent density, open porosity, water absorption, compressive strength and durability were examined. Results of technological research suggest the possibility of the application of the waste sludge from washing aggregates in building ceramics technology as bricks materials. Waste sludge from washing dolomite aggregates can be used as the main raw material of building ceramics masses. Without any additional technological operations (e.g. drying or grinding), the material with satisfactory properties was obtained. According to durability results all obtained materials can be used for masonry protected against water penetration and without contact with soil and ground water and also for masonry subjected to passive exposure (F0 – according to the standard EN 771-1).Ilość odpadów z płukania kruszyw dolomitowych stale wzrasta. Kruszywa płucze się w celu usunięcia zanieczyszczeń ilastych. Odpady z płukania charakteryzują się wysoką zawartością minerałów ilastych oraz węglanów. Ich właściwości zależą od charakterystyki płukanego surowca oraz zastosowanej technologii płukania. Problem utylizacji szlamów z płukania kruszyw wapiennych nie został rozwiązany do dzisiaj. Ich zagospodarowanie w ceramice budowlanej może przynieść korzyści ekologiczne i ekonomiczne. W pracy przedstawiono właściwości technologiczne, skład fazowy i analizę mikrostruktury materiałów wykonanych z odpadu z płukania kruszywa dolomitowego. Badania podzielono na trzy części: analizę właściwości technologicznych, analizę składu fazowego i analizę mikrostruktury. Próbki wykonane z odpadowego szlamu dolomitowego formowano w laboratoryjnej próżniowej prasie ślimakowej i wypalono w 900, 1000 i 1100°C. Dla otrzymanych tworzyw wyznaczono: gęstość pozorną, porowatość otwartą, absorpcję wody, wytrzymałość na ściskanie oraz trwałość. Wyniki badań technologicznych sugerują możliwość zastosowania odpadu z płukania kruszywa dolomitowego jako surowca mas w technologii wytwarzania ceramiki budowlanej. Bez zastosowania dodatkowych operacji technologicznych w przygotowaniu surowca uzyskano materiał o zadowalających właściwościach. Stwierdzono, że otrzymane tworzywa mogą być stosowane w murach zabezpieczonych przed przenikaniem wody, nie mających kontaktu z glebą i wodą gruntową, a także w warunkach obojętnych (wyrobach kategorii F0 zgodnie z normą EN 771-1)

Mélange, Flysch and Cliffs in the Pieniny Klippen Belt (Poland): An Overview

The Pieniny Klippen Belt (PKB) is located in the suture zone between the Central and Outer (Flysch) Carpathians. Its structure is an effect of prolonged processes of the Cretaceous–Miocene folding, thrusting and uplifting. In this zone, tectonic components of different ages and features, including strike-slip-bounded tectonic blocks, thrust units, as well as toe-thrusts and olistostromes, result in the present-day mélange characteristics of the PKB, where individual tectonic units are difficult to distinguish. In the PKB, both tectonic and sedimentary events triggered the mélange creation. The name “Klippen Belt” is derived from cliffs (German Klippen). These cliffs form harder, more erosion-resistant elements of the mélange, residing within less competent clastic deposits, sandstones, shales and marls that form flysch complexes. The cliffs often represent olistoliths, which glided down from elevated areas to the deeper basinal zones. Two olistostrome belts were distinguished. The older one resulted from subduction of the southern part of the Alpine Tethys, and the younger originated in response to the northward shift of the accretionary wedge. The other cliffs were placed within the surrounding clastic by tectonic deformational processes. The flower structure of the PKB was formed during the collision and strike-slip movement of the lithospheric plates. This structure is limited on both sides by deep-rooted faults. Several evolutionary stages could be distinguished in these areas. The rift-related stage is expressed by the opening of the Alpine Tethys that contains two major basins—Magura and Pieniny (Złatne) basins, separated by Czorsztyn Ridge. The reorganization of the Alpine Tethys basins and the development of the accretionary prism happened during the synorogenic stage. This process was initiated by the movement of the Central Carpathians. Thick flysch sequences with olistostromes were deposited in these basins. The Czorsztyn Ridge was destroyed during the late orogenic stages