TECB 213
Assignment 3 (15 %)
Instructions: The following is a part of the Results and Discussion section to a research examining the hardened properties comprising density, compressive and flexural strengths, tensile bond strength and drying shrinkage. Rewrite it by making changes to the language aspects and referencing style only. Use IEEE referencing style. The main objective is to show your ability to use words introduced. Use different words, but belong to the same category, to replace the following words that can be found in the results and discussion:
1. Quantity words
2. Invitation to view result vocabulary
3. Causality words
4. Comparison with previous studies vocabulary
5. Recommendations for improvement or future study vocabulary
3. Results and discussion
3.1. Density
The average ( mean ) density (mould-cast) of the optimum mix was 2250 kg/m3.Whilst that of well-printed specimens was a little higher( little larger) at 2350 kg/m3. This was likely because the concrete hopper was gently vibrated before delivery of the fresh concrete, and the pipe and pump system also provided a small pressure during extrusion. A similar trend occurred in a previous study on wet-spayed mortars (Austin et al., 2000; Goodier et al., 2008). Although this high performance printing concrete has only a sand aggregate, the density is much higher( much larger ) than that of ordinary mortars (1800 kg/m3) and sprayed mortars (Austin et al., 2000) (i.e. 1800–2000 kg/ m3 on average). The high density is also attributed to the grading and homogeneity resulting in high strengths and low shrinkage.
3.2. Compressive strength
The mould-cast cube compressive strength at 28 days was typically 107 MPa but varied with the admixtures and their dosages. The superplasticiser appeared to delay the hardening of concrete at an early age. However, as expected and also in agreement with previous work (American Concrete Institute, 1998; UK Cement