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Extrusion-based digital construction (DC) approaches make it feasible to overcome constraints of conventional construction, namely, high formwork costs, long total construction times, low productivity and geometrical inflexibility. However, to date, no satisfactory solutions for extruding strongly inclined and horizontal elements are available. A wood-starch-composite has been systematically developed as a sustainable support material (SM) for extrusion-based DC.

Material and process-specific requirements were identified for this purpose, and a feasible process chain was developed. A parametric study was conducted to determine the influence of SM composition on its extrusion feasibility and compressive strength. Various compositions with two starch types and two wood particle shapes were tested. New, specific testing methods were developed. Selected compositions were tested using a 3D-printing device to verify extrudability and form stability.

Relationships between material compositions of SM and its rheological and mechanical properties were identified. All mixtures showed sufficient compressive strength in respect of the loading conditions analysed. However, their flow properties varied significantly. A mixture of native maize starch and wood floor was identified as the best variant (compressive strength 2.3 MPa).

Comprehensive investigations of possible process chains, as well as full-scale demonstration and optimisation of the process parameters, were not in the scope of this paper. Such investigations are intended in further studies.

The general applicability of wood-based SM for DC with cement-based construction materials was proved.

The findings offer a novel and promising solution for 3D-printing of non-vertical concrete elements. Experimental setup and material compositions are detailed to ensure reproducibility.

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All items listed may be borrowed from the Aslib Library, except those marked, which may be consulted in the Library.

All items listed may be borrowed from the Aslib Library, except those marked *, which may be consulted in the Library.

This paper evaluates the effectiveness of cognitive-behavioural therapy (CBT) in the treatment of social anxiety with a 19-year-old man with intellectual disabilities (ID) and autistic spectrum disorders.

The intervention was evaluated using an A-B single case design. An idiosyncratic measure was developed to measure anxiety symptoms on a daily basis. The brief symptom inventory (BSI; Derogatis, 1975) measured symptom patterns across nine psychological dimensions and was administered at initial assessment, pre-intervention and post-intervention.

Visual and statistical analysis of the data showed that anxiety severity dramatically reduced throughout the course of therapy, reaching and maintaining zero and this was statistically significant. Data seemed to show that sudden gains in the reduction of anxiety severity occurred during the relaxation and cognitive phases of intervention. This sudden gain coincided with an increase in daily activities, and exposure to more anxiety provoking events which was also statistically significant. Global anxiety scores, as measured by the BSI, showed a notable reduction at post-treatment.

This paper demonstrates that CBT can bring about meaningful improvements in the treatment of anxiety in people with ID and autism and suggests that further exploration with the wider population is needed.