คุณสมบัติด้านกำลังอัดและการหดตัวแบบแห้งของปูนฉาบที่ผสมเปลือกหอยบด

Abstract

This research investigated the use of ground seashells including short-necked clam, green mussel, oyster and cockle for developing plastering cement suitable for general usage. This work was focused on the influence of variables on the properties of plastering mortar in accordance with the Thai Industrial Standard (TIS 1776) compared with ordinary Portland cement (OPC) mortars. Also the properties studied include the compressive strength and drying shrinkage. The parameters are the percentage replacement of ground seashells at the levels of 5%, 10%, 15% and 20% by weight of total binder. The results indicated that the amount of calcium carbonate (CaCO₃) of ground short-necked clam shell, green mussel shell, oyster shell and cockle shell are comparable and not much different. The increased amount of ground seashells caused the decrease in strength of plastering mortar, the decrease of water requirement and the increase of setting time of the mixture. For the drying shrinkage of mortar, using ground short-necked clam shell and ground oyster shell in the mixture caused the decrease in shrinkage of plastering mortar compared with an OPC mortar. In conclusion, all of the mortar mixtures containing ground seashells yielded the properties passing the TIS standard for plastering mortar.