Unfired brick is considered as a more environmentally friendly material than fired brick. It has lower mechanical properties than that of fired brick where humidity influences both bricks. Physical and mechanical properties of unfired bricks made of three kinds of mixtures were studied experimentally under three humidity conditions. The first kind of unfired brick was made only with soil and water while the second type was made of a mixture of soil, water and lime, and the third type was a mixture of soil, water, lime and uniform treated coir where 4% of lime mass was substituted with coir mass. Physical properties evaluation consisted of water content, absorption, volume shrinkage and density of those unfired bricks. Some variations occur in the third type of unfired bricks physical test results, where in general in more humid conditions there are tendency to have higher density, higher absorption, higher water content and less volume shrinkage compared to two other types of unfired bricks. Mechanical properties are evaluated by its modulus of rupture, compressive strength and modulus of elasticity. It is found that the addition of 4% treated 2.5 cm coir gives better mechanical properties in humid conditions compared to others types of unfired bricks. AbstrakEvaluasi Eksperimental Tiga Kondisi Kelembaban terhadap Properti Fisik dan Mekanik Tiga Campuran Bata Tidak Dibakar. Bata tidak dibakar dianggap lebih ramah lingkungan dibanding bata dibakar. Bata tidak dibakar memiliki properti mekanik yang lebih rendah daripada bata dibakar, dimana kelembaban berpengaruh pada keduanya. Properti fisik dan mekanik bata tidak dibakar yang dibuat dari tiga macam campuran dipelajari secara eksperimental terhadap tiga kondisi kelembaban. Tipe pertama dari bata tidak dibakar dibuat hanya dengan tanah dan air, sedangkan tipe kedua terbuat dari campuran tanah, air dan kapur; dan tipe ketiga terbuat dari campuran tanah, air, kapur dan serabut kelapa seragam yang sudah mendapat perlakuan sebelumnya dimana 4% dari massa kapur diganti dengan massa serabut kelapa. Evaluasi properti fisik terdiri dari kadar air, absorbsi, susut volume dan densitas bata tidak dibakar tersebut. Beberapa variasi muncul pada hasil tes fisik tipe bata ketiga, dimana secara umum pada kondisi lebih lembab terdapat kecenderungan untuk memiliki densitas lebih tinggi, absorbsi lebih tinggi, kadar air tinggi dan susut volume lebih kecil dibandingkan terhadap kedua jenis lainnya bata tidak dibakar. Properti mekanik dievaluasi oleh modulus keruntuhan, kuat tekan dan modulus elastisitasnya. Diketemukan bahwa penambahan 4% serabut memberikan properti mekanik yang lebih baik pada kondisi lembab dibandingkan tipe bata tidak dibakar lainnya.

The paper discusses strength-time relation of unfired soil-lime bricks in presence of different water content of soil as one of principal materials for the brick making. Two batches of soil-lime bricks were made with a mixture of lime, soil and water with a mass proportion of 1: 5.7: 1. Water contents of the first and second batch of soil are 30% and 40.581% respectively. Both batches of brick underwent compression and three point bending test. Absorption and physical change of bricks were also evaluated. Experimental investigation reveals that for both batches of bricks, up to 90 days compressive strength decreases a little but modulus of rupture rapidly decreases with time. The study shows that unfired soil-lime bricks with lower soil water content resulted in better strength performances compared to those with higher soil water content.

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