Industrial scale study of red gypsum paver as green construction material / Muhammad Faisal Baderolhissam

Faculty of Chemical and Process Engineering Technology

Thesis (Master of Science) -- Universiti Malaysia Pahang – 2021

Includes bibliographical references

Red Gypsum (RG) is one of the most abundant industrial solid wastes, classified as scheduled wastes, amounting to more than 8 million tons accumulated at designated landfills within the vicinity of the waste generators. At present, no effective method of RG utilization has been adopted to significantly reduce the accumulated solid waste at sites. In relation to this, the current study was conducted to investigate suitability of using RG in paver manufacturing thereby offers a solution which can significantly reduce the piling of RG at sites should the study showed positive results. In order to give a more realistic results, the study was conducted using small scale industrial facility with a capacity of around 5,000 pavers per day production. Initial study was conducted by varying the percentage of sand replacement from 20% up to 100%, at sand to cement (s/c) ratio of 1:1 and water to cement (w/c) ratio of 0.4. The results showed a decreasing trend of compressive strength in relation to increasing percentage of sand replacement by RG. Since 20% replacement complied with class 4-5 of MS 76:1972, study was further conducted within the range of 0 – 20% replacement to identify the best operating condition for the system. Paver with 5% sand replacement was found to have the highest compressive strength, recorded at 39.8 MPa and 42.3 MPa or the 7thand 28th day curing, higher than the 0% sand replacement which recorded at 40.0 MPa for 28th day curing. Since RG is not a pozzolanic material, it was clear that the increase in compressive strength at 5% sand replacement was due to the filling of fine RG particles in the void between sand particles making the interlocking tighter. Further increase of RG content in the paver resulted in reducing the compressive strength since excess fine RG particles sipping through the interfaces between the interlink sand particles, hence weaken the interlocking arrangement. The results and explanation were supported by the UPV readings which recorded highest value at 5% sand replacement, and with all samples of RG presence recorded higher value than the pure sand-cement paver sample. Commercial aspect of RG paver manufacturing was studied based on the optimum operating condition, and the analysis on the effect of water/cement ratio on the cost effectiveness and marketability of the product. As an impact of this industrial scale study, RG were found suitable to be used as sand replacement material in paver which can be utilized as construction material rather than dumped at designated landfill. Replacement of sand by RG also lowering the cost per unit of paver with a saving of RM52,000 yearly for paver manufacturing plant with production of 50,000 units of paver per day.