This review deals with the state-of-the-art of waste tyre pyrolysis for the first time in literature. Pyrolysis has been addressed as an attractive thermochemical process to tackle the waste tyre disposal problem while allowing energy recovery. Pyrolysis enables the separation of carbon black from tyres and the volatile matter released (condensable and non-condensable compounds) has the potential of renewable energy recovery given the significant proportion of natural rubber present in the tyre. Given this waste-to-energy pathway, a comprehensive review has been carried out in order to show the effects of the main process conditions (heating rate, temperature, pressure, carrier gas flow rate and type, volatiles residence time and pyrolysis time) on the physicochemical properties and distributions of the resulting products (gas, liquid and solid fractions). It has also been reviewed the influence of the size and composition of the feedstock. All reported results have been framed regarding the type of reactor as well as the experimental conditions used to avoid contradictions among the large number of publications on the subject. It is shown that the occurrence of secondary reactions is very sensitive to the interaction of the aforementioned variables. Also, the main properties of the pyrolytic products are pointed out. The liquid and gaseous fractions obtained are a valuable fuel source; while the solid fraction (char) has the recovery potential of low- grade carbon black or as carbon adsorbent after applying an activation step. Special attention has been given to the liquid fraction, highlighting its properties as alternative fuel in compression ignition engines.

Waste tyre pyrolysis – A review

Progress in used tyres management in the European Union: A review

Concrete made with recycled tire rubber: Effect of alkaline activation and silica fume addition

Recycling of waste tire rubber as aggregate in concrete: durability-related performance

Assessment of mechanical and durability properties of concrete containing waste rubber tire as fine aggregate

The main objective of this study was to investigate the potential utilisation of rubber waste in cementitious matrix, as fine aggregates, to develop lightweight construction materials. Composites containing different amounts of rubber particles, as partial replacement to cement by volume, were characterised by destructive and non-destructive testing. Five designated rubber contents varying from 10% to 50% by volume were used. The 28-days physical, mechanical and hydraulic transport properties of the cement composite were determined. Analyses included dry unit weight, elastic dynamic modulus, compressive and flexural strengths, strain capacity, and water absorption. Test results of the physico-mechanical behaviour indicated that the increase in rubber content decreases the sample unit weight with a large reduction in the strengths and elastic modulus values of the composites. Results have only shown that the introduction of rubber particles significantly increases the strain capacity of the materials. However, rubbers into cement paste enhances the toughness of the composite. Although the mechanical strengths were reduced, the composite containing 50% of rubber particles satisfies the basic requirement of lightweight construction materials and corresponds to “class II”, according to the RILEM classification. Test-results of the hydraulic transport properties revealed that the addition of rubber particles tends to restrict water propagation in the cement matrix and reduces water absorption of the composite. The decrease of the sorptivity-value is favourable to the durability of the specimen structures.

Physico-mechanical properties and water absorption of cement composite containing shredded rubber wastes

Characterization of flax lime and hemp lime concretes: Hygric properties and moisture buffer capacity

Characterization and comparison of hygric properties of rape straw concrete and hemp concrete

Effect of moisture and temperature on thermal properties of three bio-based materials

This paper focuses on the assessment of the hygrothermal performance of a straw bale house in the Picardie, a region of France. The house was built using a wooden load bearing frame filled with straw bales. Laboratory and in situ tests were carried out in this study. In the first part, the thermal conductivity of straw bales was measured in relation to the orientation of the straw fibers. The thermal resistance of a wall built in the laboratory, respecting the real construction parameters, was assessed. The obtained U-value was compared to those of different walls used in civil field engineering. The second part of this paper continues with an assessment of the hygrothermal performance of a real straw bale house. Temperature and relative humidity measurements were recorded during more than one year, using sensors that were placed in indoors and outdoors, and at various depths of the walls and floors. Finally, this paper is completed by a dynamic thermal simulation of the house, based on experimental laboratory investigations. During winter the simulated heating requirements are estimated at 59 kW h/m2. Moreover, the simulation under summer conditions shows the major influence of the building envelope on the thermal comfort. Thus, straw bale walls seems to provide significant thermal inertia in summer.

T. Langlet

Papers

Physico-mechanical properties and water absorption of cement composite containing shredded rubber wastes

Characterization of flax lime and hemp lime concretes: Hygric properties and moisture buffer capacity

Characterization and comparison of hygric properties of rape straw concrete and hemp concrete

Effect of moisture and temperature on thermal properties of three bio-based materials

Hygrothermal performance of a straw bale building: In situ and laboratory investigations