Properties of Lightweight Papercrete Made with Pumice

This study assessed the strength and other properties of papercrete (a paper and mortar composite) produced by using pumice as fine aggregate instead of sand. Papercrete samples containing ordinary Portland cement (OPC), paper sludge and pumice as fine aggregate were produced (Sample PP) and compared to control samples containing OPC, paper sludge and 2 sand (Sample SP). The experimental results show that Sample PP (3.86N/mm ) recorded a 2 55% increase in compressive strength over Sample SP (1.74N/mm ) at 28 days. Sample PP (563Kg/m ) also increased in density over Sample SP (555Kg/m ) at 28 days. In other tests, Sample PP showed a similar response to water absorption and fire reaction as Sample SP.  Additionally, Sample PP recorded a lower thermal conductivity  (0.630W/moK) than Sample SP (0.657W/m oK). It was concluded that when pumice is used as fine aggregate to produce papercrete, it substantially improves strength and lowers thermal conduction in addition to behaving in similitude to ordinary papercrete in other properties. Keywords: Pumice, Papercrete, Compressive strength, Density, Thermal conductivity &nbsp

Assessment of natural radioactivity levels in stony sand from Black Stone Beach of Kuantan, the Peninsular Malaysia

Black Stone Beach (or Pantai Batu Hitam) of Kuantan, Malaysia is a windy but unique beach located on the coastal strip, and has become an attraction for tourists from within and outside the country for many years due to its scenic dark rock formations. Considering the radiological safety of human health, a study was conducted to assess the concentrations of naturally occurring radioactive materials in the beach environment. Activity concentrations of primordial radionuclides 226Ra, 232Th, and 40K in the stony sand samples collected from the beach area were assessed by using HPGe γ-ray spectrometry. The measured external gamma radiation dose rates and the activity concentrations were found to ranges 22–31 nGy.h−1 and 9.8 ± 0.6 to 12.4 ± 0.7 Bq.kg−1, 6.8 ± 0.5 to 8.8 ± 0.6 Bq.kg−1 and 209 ± 11 to 354 ± 17 Bq.kg−1 for 226Ra, 232Th and 40K, respectively. The mean values of typical radiological indices such as radium equivalent activity (Raeq) and annual effective dose were found to be 17.82 Bq.kg−1 and 10.86 × 10−3 mSv.year−1 which were far below the world average values of 370 Bq.kg−1 and 2.4 mSv.year−1 set by the UNSCEAR, respectively. Present results served as an important reference for any future radiological study in Kuantan, Malaysia