Paving blocks from ceramic tile production waste

This paper presents the use of waste mud from ceramic tile production as the main component in paving blocks. Compressive strength values of the blocks were compared with the standard value as prescribed by the Thailand Industrial Standard. The waste mud was first characterized using XRD, XRF, SEM, Laser diffraction particle size analyzer and sieve analysis. Paving blocks were subsequently prepared by mixing the waste mud with Ordinary Portland cement (OPC) and compacted using a hydraulic press. Water was added to the cement–mud mix to assist compaction and to strengthen the blocks by hydration of OPC. Effects of water and cement content, immersion in water, as well as compaction pressure on compressive strength were subsequently studied. Increasing compaction pressure and also immersion in water for 5 min every 24 h were found to enhance densification and thus compressive strength of the test samples. The blocks containing 15 wt% cement required a long curing period of up to 28 days for their compressive strength to reach the standard requirement while the compressive strength of the blocks containing 25–30 wt% cement exceeded the standard requirement after curing for only 7 days.