About half of the cost of deep soil stabilization installation works is attributed to the cost of binder materials, mainly cement. Wastepaper sludge ash (WSA) is considered as a potential substitute for cement in construction of lime-cement columns. Suitability and performance of lime-WSA mixture in deep stabilization of quick clay are presently investigated at NTNU, Norway. Mineralogical and chemical analyses of WSA, laboratory mixing methods and proportioning and strength and deformation characteristics using unconfined compression tests were performed on lime-WSA mixtures and compared with the commonly applied lime-cement mixtures. The results show that equal proportions of lime and WSA produce the best results, with higher unconfined compressive strength, stiffness and unit weight for samples with 100 kg/m3 binder dose rate compared to samples with 150 kg/m3 . Stabilizing effects produced by lime-WSA mixtures are comparable to those of lime-cement binders, in addition to economic and environmental advantages of reusing WSA. However, it takes about 75 days for lime-WSA mixtures to achieve engineering properties equivalent to 28-days old lime-cement mixtures. Eighteen months old field samples from actual lime-cement and lime-cement-WSA columns were tested, where the lime-cement-WSA samples tested about five times stronger and fifty times less permeable, compared with the corresponding lime-cement samples. Key words: Deep stabilization, lime-cement column, wastepaper sludge ash, quick clay
