chapter  66
10 Pages

LONG-TERM DURABILITY OF GRC

ByA.J.MAJUMDAR, B.SINGH

The first commercial alkali-resistant (AR) glass fibre for cement reinforcement, trademarked Cem-FIL, was launched by Pilkington Brothers PLC in 1971 following pioneering work by Majumdar and Ryder (1968) a few years earlier. Using the spraydewatered method several glass reinforced cement (grc) boards containing nominally 5 wt% of 34−38 mm long Cem-FIL fibres were fabricated at the Building Research Establishment at that time using neat ordinary Portland cement (OPC) as the matrix. After moist curing in the Laboratory for the first seven days the boards were cut into specimen coupons, 150×50 mm and approximately 10 mm thick, and distributed to three

different environments-dry air 40% rh) at 20°C, under water at 20°C and natural weathering on the BRE site at Garston. The specimen coupons were tested for their mechanical properties after pre-determined intervals and the results up to 10 years have been published (Building Research Establishment 1976, 1979). A limited number of specimens were kept for a longer time study and these have been tested recently, 20 years after they were made. The results are given in this report.