DESIGN AND MODELLING OF 222RN EMANATIONS IN BUILDINGS UTILISING BASIC BUILDING MATERIALS AND FOAMED LIGHT CONCRETE

 

DESIGN AND MODELLING OF 222RN EMANATIONS IN BUILDINGS UTILISING BASIC BUILDING MATERIALS AND FOAMED LIGHT CONCRETE

ABSTRACT

In this research 222Rn concentrations were measured for basic construction materials, concrete blocks group (concrete and light foamed concrete) and concrete room prototype group (concrete and light foamed concrete). 222Rn concentration measurements were obtained by using At Ease Radon Monitor Model 05-420 manufactured by Honeywell Incorporation and Continuous Radon Monitor model 1027 manufactured by Sun Nuclear Corporation.

 

Results from this research shows that the current 222Rn concentration level is directly proportional to temperature and inversely proportional to humidity. The used two different 222Rn detectors did not give any significant different (0.1 pCi/L) on current 222Rn concentration level. Basic construction material group consisted of granite stones gave highest mean 222Rn concentration level (3.3 pCi/L, 3.3 pCi/L) for the 2 detector, respectively, compared with river sand (0.8 pCi/L, 0.8 pCi/L), Portland cement (0.3 pCi/L, 0.3pCi/L) and foamed material (0.2 pCi/L, 0.2 pCi/L). For concrete group, concrete grade 7 showed as highest mean 222Rn concentration level (4.1 pCi/L, 4.1 pCi/L) compared with concrete grade 25 (3.5 pCi/L, 3.4 pCi/L), concrete grade 45 (2.3 pCi/L, 2.3 pCi/L), light foamed concrete 1 (1.7 pCi/L, 1.7 pCi/L), light foamed concrete 2 (1.4 pCi/L, 1.4 pCi/L) and light foamed concrete 3 (1.0 pCi/L, 1.0 pCi/L).

 

 

For concrete room prototype group, PKBG25 ground floor acquired highest mean 222Rn concentration level (4.5 pCi/L, 4.5 pCi/L) compared with PKRB2 ground floor (2.4 pCi/L, 2.5 pC/L). PKBG25 second floor also obtained high mean 222Rn concentration level (3.4 pCi/L, 3.5 pCi/L) compared with PKRB2 second floor (1.2 pCi/L, 1.3 pCi/L). PKBG25 ground floor with fan attached to the prototype concrete obtained high mean 222Rn concentration level (3.2 pCi/L, 3.3 pCi/L) compared with PKRB2 ground floor (fan) (1.2 pCi/L, 1.3 pCi/L). The same finding goes to PKBG25 second floor (fan), obtained high mean 222Rn concentration level (2.5 pCi/L, 2.6 pCi/L), compared with PKRB2 second floor (fan) (0.8 pCi/L, 0.9 pCi/L).

 

Moreover, there was a positive relationship for mean 222Rn concentration level between total material ratio (Portland cement, river sand and granite stones) which was used in concrete construction with ordinary concrete and available light foamed concrete sample.

 

This research found that the combinations of 3 factors, altitude, light foamed concrete and ventilation (fan) were identified as effective parameters to reduce 222Rn concentration level by 64.7%. Increasing the altitude, decreased current 222Rn concentration level. The used of fan in concrete room prototype reduced the current 222Rn concentration level compared with closed concrete room prototype. The results show application of light foamed concrete able to reduce current 222Rn concentration level significantly compared with using ordinary concrete as building material.

 

REKA BENTUK DAN PERMODELAN EMANASI 222RN DALAM BANGUNAN MENGGUNAKAN BAHAN ASAS BINAAN DAN KONKRIT RINGAN BERBUSA

 

ABSTRAK

 

Kajian ini dijalankan bagi mengukur paras kepekatan 222Rn bagi 3 kumpulan sampel yang dipilih dan direkabentuk terdiri daripada kumpulan asas bahan binaan, kumpulan konkrit (blok konkrit biasa dan konkrit ringan berbusa) dan kumpulan prototaip bilik konkrit (konkrit biasa dan konkrit ringan berbusa). Sebanyak 3 eksperimen dijalankan dengan menggunakan 2 alat pengesan paras kepekatan 222Rn iaitu At Ease Radon Monitor model 05-420 yang dikeluarkan oleh Honeywell Incorporation dan Continuous Radon Monitor model 1027 dari Sun Nuklear Corporation.

 

Hasil daripada kajian menunjukkan bahawa paras kepekatan 222Rn semasa berkadar terus dengan suhu dan berkadar songsang dengan kelembapan. Kajian ini juga mendapati, penggunaan dua pengesan 222Rn yang dari model berbeza tidak memberi kesan signifikan kepada paras kepekatan 222Rn semasa kerana nilai perbezaan bacaan yang kecil iaitu sebanyak 0.1 pCi/L. Hasil daripada eskperimen 1 mendapati, kumpulan asas bahan binaan yang terdiri daripada batu granit menghasilkan paras kepekatan 222Rn min tertinggi bagi dua pengesan 222Rn yang digunakan, (3.3 pCi/L, 3.3 pCi/L) berbanding pasir sungai (0.8 pCi/L, 0.8 pCi/L), simen Portland (0.3 pCi/L, 0.3 pCi/L) dan bahan busa (0.2 pCi/L, 0.2 pCi/L). Manakala bagi kumpulan konkrit, konkrit biasa gred 7 mencatat paras kepekatan 222Rn min tertinggi (4.1 pCi/L, 4.1 pCi/L) berbanding konkrit biasa gred 25 (3.5 pCi/L, 3.4 pCi/L), konkrit biasa gred 45 (2.3 pCi/L, 2.3 pCi/L), konkrit ringan berbusa 1 (1.7 pCi/L, 1.7 pCi/L) konkrit ringan berbusa 2 (1.4 pCi/L, 1.4 pCi/L) dan konkrit ringan berbusa 3 (1.0 pCi/L, 1.0 pCi/L). Bagi kumpulan prototaip bilik konkrit, Prototaip Konkrit Biasa Gred 25 (PKBG25) tingkat bawah menghasilkan paras kepekatan 222Rn min tertinggi (4.5 pCi/L, 4.5 pCi/L) berbanding Prototaip Konkrit Ringan Berbusa 2 (PKRB2) tingkat bawah (2.4 pCi/L, 2.5 pCi/L). PKBG25 tingkat atas juga menghasilkan paras kepekatan 222Rn min tinggi (3.4 pCi/L, 3.5 pCi/L) berbanding PKRB2 tingkat atas (1.2 pCi/L, 1.3 pCi/L).

 

Hasil daripada eksperimen 2 dan 3 mendapati, PKBG25 tingkat bawah (kipas) menghasilkan paras kepekatan 222Rn min tinggi (3.2 pCi/L, 3.3 pCi/L)

berbanding PKRB2 tingkat bawah (kipas) (1.2 pCi/L, 1.3 pCi/L). Begitu juga PKBG25 tingkat atas (kipas) menghasilkan paras kepekatan 222Rn min tinggi (2.5 pCi/L, 2.6 pCi/L), berbanding PKRB2 tingkat atas (kipas) (0.8 pCi/L, 0.9 pCi/L). Selain daripada itu, terdapat hubungan secara positif bagi paras kepekatan 222Rn min antara jumlah nisbah bahan (simen Portland, pasir sungai dan batu granit) yang digunakan dalam pembuatan konkrit dengan sampel konkrit biasa dan sampel konkrit ringan berbusa yang telah siap dibina.

 

Kajian ini mendapati, faktor paras ketinggian, penggunaan konkrit ringan berbusa dan kaedah aliran udara (kipas) adalah dikenalpasti sebagai satu alternatif yang amat berkesan untuk menurunkan peratusan paras kepekatan 222Rn sesuatu sampel konkrit sehingga 64.7 %. Semakin tinggi faktor ketinggian semakin kurang paras kepekatan 222Rn semasa. Begitu juga dengan penggunaan kipas dalam prototaip bilik konkrit dapat menurunkan paras kepekatan 222Rn semasa berbanding prototaip bilik konkrit yang tertutup. Hasil kajian ini menunjukkan penggunaan konkrit ringan berbusa dapat mengurangkan paras kepekatan 222Rn berbanding penggunaan konkrit biasa yang sering digunakan dalam sektor pembinaan.