Effect of Walnut-Shell Additive on the Structure and Characteristics of Concrete

Abstract

The partial replacement of the mineral components of concrete with natural renewable analogues in full possession of the performance characteristics of the final material, allows not only the concrete-production process to be made more environmentally friendly and inexpensive, but also to solve an important task for the agricultural industry, which is that associated with waste disposal. The scientific novelty of the work is in the obtaining of new concrete compositions by the partial replacement of coarse aggregate with a natural analogue in the form of a walnut shell, which has the maximum ratio of the strength of the composite to its density, as well as in identifying new dependencies of strength and density and their ratio on the amount of replacement of mineral coarse-aggregate walnut shell. The main goal of this article was to analyze the effect of composition factors on characteristics of concrete with partial replacement of large aggregates with walnut shells and to search for the optimal compound that would make it possible to obtain concrete with a minimum decrease in strength characteristics with a maximum decrease in concrete density. Cubes and prism laboratory samples were made from concrete of normal density with the replacement of coarse aggregate by 5, 10, 15, 20, 25 and 30%, by volume. The main mechanical properties, such as density, strength (compressive, tensile, tensile strength in bending) of the concrete samples were studied. The investigation used standard methods and scanning electron microscopy. An increase into strength characteristics up to 3.5%, as well as the maximum ratio of strength to density of concrete, was observed at a walnut-shell dosage of 5%. Effective partial replacement of coarse aggregate with walnut shells leads to a reduction in the consumption of crushed stone by up to 10% and a decrease in the mass of concrete by up to 6%.

Alteration of Structure and Characteristics of Concrete with Coconut Shell as a Substitution of a Part of Coarse Aggregate

“…The designs of the concrete mixture of the control composition and the mixtures with different CS contents are compiled in Table 6. The choice of the proportions of the concrete mixtures (water-cement ratio, percentage of CS and other parameters) was based on the concrete compositions already selected by us in previous works [14,15] and the works of other authors [33,34,46], with their adjustment related to the properties of the components used [51].…”

“…At the same time, materials scientists are faced with the question of studying the fundamental nature of the processes and physicochemical processes that take place during the formation of the structure and properties of building materials using plant waste. Of particular difficulty and at the same level of interest is the determination of the most rational quantities and the degree of compatibility and effectiveness of the combination of plant wastes in the body of mineral components of other materials, including concrete [ 5 , 13 , 14 , 15 ]. Recently, the question of the inconsistency of the concept of sustainable development with this approach of using natural mineral resources, for example river sand and crushed stone, for the needs of the construction industry has been increasingly raised [ 16 ].…”

“…It is becoming promising to develop technologies that can reduce the rate of depletion of natural non-renewable components of concrete [ 4 , 17 , 18 ]. One of the most promising methods to solve this problem is the complete or partial substitution of the mineral components of concrete with natural renewable plant analogues that are industrial and agricultural waste; this solves a number of problems for these industries [ 14 , 15 , 19 , 20 ]. However, new renewable materials should not reduce the strength characteristics of concrete or adversely affect its durability [ 21 ].…”

Valorization of Cork Stoppers, Coffee-Grounds and Walnut Shells in the Development and Characterization of Pectin-Based Composite Films: Physical, Barrier, Antioxidant, Genotoxic, and Biodegradation Properties

“…It can be incinerated or used as a raw material in different industrial processes, such as flours and bases for soaps [ 16 , 21 ]. More recently, Beskopylny et al [ 22 ] used walnut shells as an additive in the production of concrete. In another study, Sowińska-Baranowska et al [ 23 ] showed the potential application of walnut shells as biofillers for natural rubber composites.…”

Experimental Study on the Durability Performance of Sustainable Mortar with Partial Replacement of Natural Aggregates by Fiber-Reinforced Agricultural Waste Walnut Shells

“…The test results showed that when coarse and fine aggregates were replaced with walnut shells separately, the dry density and mechanical properties of the mortar decreased except for water absorption, and the overall performance was best when coarse and fine aggregates were replaced together. Alexey N. Beskopylny et al [23] utilized walnut shells as equal volume replacements for coarse aggregates in concrete (5% to 30%), and the density, compressive, flexural, and tensile properties of the concrete were studied. The test results showed that at 5% replacement of walnut shells, the strength properties of the concrete increased by 3.5%, the strength-to-density ratio reached its maximum value, a 10% reduction in crushed stone consumption, and a 6% reduction in concrete mass.…”