Bulletin of the Geological Society of Malaysia, Volume 53, June 2007, pp. 81 – 88

Potential alkali-silica reaction in aggregate of deformed granite

Ng Tham Fatt¹ and Yeap Ee Beng²

¹Department of Geology, Universiti Malaya, 50603 Kuala Lumpur, Malaysia

²No 45, Jalan SS15/6A, 47500 Subang Jaya, Selangor, Malaysia

Abstract: Granite is the most important source of construction aggregate in Peninsular Malaysia and is widely used in concrete. Granite aggregate is generally considered as not alkali-silica reactive. However, deformation by faulting has generated a diverse variety of deformed granites that may contain deleterious minerals. Petrographic examination and mortar-bar test were carried out to assess potential alkali-silica reactivity. Strained quartz and microcrystalline quartz are the main potentially deleterious mineral in deformed granites. The mortar-bar test recorded marginally deleterious to deleterious expansions. The expansion values can be related to the total strained and microcrystalline contents. Deformed granites with over 12% of total strained and microcrystalline quartz is expected to cause marginal to deleterious expansion and this should be verified by the mortar bar test. The deformed granites generally will not pose serious problems in the production of concrete aggregates as they constitute only a small proportion of the extracted rocks.

https://doi.org/10.7186/bgsm53200713

Abstrak: Batuan granit adalah sumber agregat pembinaan yang paling penting di Semenanjung Malaysia yang lazim digunakan dalam konkrit. Secara amnya, agregat granit dianggap tidak mempunyai kereaktifan alkali-silika. Sesar yang berlaku pada batuan granit telah menghasilkan pelbagai jenis batuan tercangga yang mungkin mempunyai mineral mudarat. Ujian petrografi dan bar mortar telah dijalankan untuk menilai potensi reaktiviti alkali-silika. Kuarza yang mengalami terikan dan kuarza mikrokristalin adalah mineral mudarat yang utama dalam granit tercangga. Ujian bar mortar menunjukkan terdapatnya pengembangan yang marginal hingga mudarat yang boleh merosakkan konkrit. Nilai pengembangan boleh dikaitkan dengan jumlah kandungan kuarza terikan dan mikrokristalin. Granit tercangga yang mengandungi lebih daripada 12% kuarza terikan dan mikrokristalin dianggap boleh menyebabkan pengembangan dan ini perlu ditentukan melalui ujian bar mortar. Secara amnya granit tercangga tidak akan menyebabkan masalah yang besar dalam penghasilan agregat konkrit kerana kandungannya dalam batuan adalah sedikit.