Performance-Related Assessment of the Potential Use of Sawing Sludge in Cementitious Fluidized Thermal Backfills

Abstract

The management of sawing sludge originated from cutting operations of ornamental stones represents a challenging task as a consequence of its peculiar composition that includes non-negligible amounts of heavy metals resulting from the wear and tear of cutting tools. The aim of the research work presented in this paper was to investigate the feasibility of using these by-products as supplementary constituents of cementitious mixtures employed for the formation of Fluidized Thermal Backfills (FTB). These mixtures are designed and produced for filling operations in pavement subgrades in which high-voltage electrical transmission cables are buried for protection purposes. Two different types of sawing sludge were thoroughly analyzed from a physical and chemical point of view and thereafter employed for the laboratory production of four FTB mixtures. Then, these were subjected to thermal, mechanical, and environmental tests in order to verify their suitability for their intended use. All investigated FTB mixtures exhibited a satisfactory and stable thermal conductivity, and they also displayed enhanced stiffness properties in comparison to standard subgrade and sub-base materials. Controversial results were obtained with respect to environmental properties resulting from leaching tests, thus suggesting that further investigations are needed before any full-scale application can take place.

A Sustainable Cold-Recycled Solution for the Surface Finishing of Unpaved Rural Roads

“…The aim of achieving an acceptable level of workability of the investigated CRMs suggested the adoption of an approach which is similar to that normally referred to in the design of self-compacting cementitious mixtures [ 35 , 45 , 46 , 47 , 48 , 57 ]. Thus, dosages of RA, sand and mineral sludge were obtained by considering the target size distribution proposed by Funk and Dinger [ 58 ], given by Equation (1): where D represents the diameter of aggregate particles (in mm), P(D)—expressed in %—is the cumulative percentage passing the sieve with opening equal to D; D max is the maximum diameter of aggregate particles in the mixture (in mm, fixed at 12.5 and corresponding to a P(D) equal to 100%); D min is the minimum diameter of aggregate particles in the mixture (in mm, assumed to be equal to 5 μm); and q is the so-called distribution modulus, which may vary between 0 and 1 and defines the balance of coarse and fine aggregates within the aggregate skeleton (as q decreases, the aggregate skeleton of the mixture becomes finer).…”

Life Cycle Assessment of Environmentally Friendly Solutions for the Construction of Unpaved Rural Roads

“…Recycled materials of different origins, such as construction and demolition waste [7][8][9][10][11][12][13], plastics [14][15][16][17][18][19][20], rubber [21][22][23][24][25][26], reclaimed asphalt [10,19,24,25,[27][28][29][30][31][32][33][34][35][36][37], and mineral sludge [38][39][40][41][42][43][44], have the potential for recycling in road pavement materials, making the performance of the corresponding mixtures in which they are employed comparable to those obtained with totally virgin components.…”