This research evaluated, from the ecological and economical points of view, the potential use of high volumes of incineration ash from sewage sludge in CLSM (Controlled Low Strength Materials). Moreover, a dust powder from crushed stone production is used as a fine aggregate. This new type of green CLSM will be a promising sustainable cementitious material for reducing CO2 emissions. In-situ early-age strength estimation of CLSM was proposed with applying simple cone penetration method (so-called YCP Test, Yamanaka Cone Penetration Test), which has been used for soil strength estimation. Test result showed that the YCP Test is found to be effective for estimating the in-situ early-age compressive strength of CLSM. Test results also showed the adequate strength development and reasonable flowability are confirmed if the mixture proportion is carefully selected. Although, the compressive strength decreases with increasing level of incineration ash, this strength reduction is easily compensated for increasing a small amount of cement content. From these tests results it is confirmed that a wide range of municipal solid waste is applicable for the materials of a new green CLSM.

This paper discusses the physical properties and leachate characteristics of a newly developed CLSM (Controlled Low Strength Materials) with a special type of cement as well as aggregate made from municipal solid waste. Eco-Cement, so-called in Japan, is the latest green cement made primarily from municipal refuse incineration ash and sewage sludge. Aggregate used in this paper was also made from the slag of municipal solid waste incinerator. High-volume off-specification fly ash was also used. This new type of green CLSM will he a promising sustainable material to reduce CO2 emissions. Test results showed an adequate strength development and reasonable flowability, especially when the mixture proportion is carefully designed. The leachate characteristics of this new CLSM are evaluated in this paper. Two types of standard tests showed acceptable leachate levels. From these tests results it was confirmed that a wide range of municipal solid waste may be applicable for the materials of the new green CLSM.

Three series of flowable slurry mixtures were made, each series with three different sources of wood ash (W-1, W-2, and W-3). The series of mixtures were: low-strength (0.3 to 0.7 MPa), medium-strength (0.7 to 3.5 MPa), and high-strength (3.5 to 8 MPa) mixtures. Tests were performed for flow, air content, unit weight, bleeding, settlement, compressive strength, and water permeability. Wood ashes W-1 and W-3 caused expansive reactions in CLSM mixtures resulting in little or slight (average 1%) net shrinkage of CLSM. Wood ash W-2 caused either significant net swelling (15% for Mixture 2-L, and 21% for Mixture 2-M) or no shrinkage (Mixture 2-H) of CLSM. The 91-day compressive strength of low-strength, medium-strength, and high-strength slurry mixtures was in the ranges of 0.38 to 0.97 MPa, 1.59 to 5.28 MPa, and 4.00 to 8.62 MPa, respectively. Overall, the slurry mixtures showed an average increase in strength of 150% (range: 25% to 450%) between the ages of 28 days and 91 days. This was attributed to pozzolanic and cementitious reactions of wood ash. In general, water permeability of CLSM mixtures decreased with age.

This research evaluated, from the ecological and economical points of view, the potential use of off-specification fly ash plus non-standard clinker ash (bottom ash or coal ash) in CLSM (Controlled Low Strength Materials). The effect of mixture proportions on the short-term as well as long-term compressive strength of CLSM is mainly investigated. A wide range of fly ash/clinker ash ratio was evaluated in order to provide a cost effective mixture design for various material costs. Two different sources of fly ash including off specification fly ash and three different sources of clinker ash were used with three levels of mixture combinations. A total of 20 mixtures was tested for the flowability, bleeding and short-term and long-term compressive strengths (strength developments up to 91 days were reported in this study). Test results showed that there is an optimum combination of fly ash clinker ash ratio on the physical properties of CLSM. Compressive strength improved with increasing the rate of replacement of clinker ash up to 5 0 percent in the case. It is found that there was no disadvantage of using off-specification fly ash and non-standard clinker ash in the physical properties of CLSM. CLSM with off-specification fly ash plus non-standard clinker ash showed excellent performance on the physical properties indicating the ecological and economical applicability to CLSM.

bleeding; bottom ash; CLSM; compressive strength; deterioration; durability; flowability; fly ash; freezing and thawing; frost heaving; mix proportioning; slump flow; used foundry sand