Self-compacting concrete between workability performance and engineering properties using natural stone wastes

Abstract

The current work aims at studying the chemical and mineralogical composition in addition to the physical properties of natural stone wastes as cement replacement and their effect on the fresh and hardened properties of self-compacting concretes (SCC). In the present study, two types of natural stone wastes were used: carbonaceous stone wastes (C) and siliceous stone wastes (S). The chemical, mineralogical, and physical characterization of the different wastes were performed using X-ray fluorescence (XRF), X-ray diffraction (XRD), water pycnometer, and Specific surface area.Nine SCC mixes coded (Ref., C10, 20, 30, 40% - S10, 20, 30, 40%) were formulated by incorporating four proportions of each type of the stone wastes other than the reference mix. The initial and final setting times, fresh density, air content, flowing - ability by slump flow, filling ability by T500 and V-funnel time, passing ability by L-box, U-box, and block assessment by J-ring were measured for the fresh mixes. For the hardened mixes, the water absorption, density, voids, compressive, flexure, and splitting tensile strengths were tested, in addition to their resistances against water penetration and chloride ion penetration, as well as sulfuric acid attack.The results revealed a slight to noticeable enhancement in the workability performance of SCCs with increasing stone wastes proportions. Using up to 40% stone wastes led to an increase in the flow- and passing-abilities by not less than (1.45%, 4.88%), while decreasing in the filling times by not less than (7.14%, 30%) as compared to the reference mix with a slight sign of bleeding and lacking an evidence of segregation or blocking.Using up to 10% stone wastes has an insignificant drop in the water absorption and density, compressive, flexure, and splitting tensile strengths values by not more than (1.64%, 0.42%, 3.65%, 3.88%, 10.51%), respectively at late age. A better resistance toward the sulphuric acid attack, in terms of strength and mass loss, was noticed for all replacement levels by not less than (17%, 13%), respectively at maximum exposure time, as compared to the reference mix.