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 work was conducted to develop two types of controlled low strength materials (CLSM) or flowable slurry utilizing post-consumer glass (broken glass or glass cullet) aggregate and fly ash. Type A CLSM consisted of glass, fly ash, cement, and water; and Type B CLSM consisted of glass, sand, cement, and water. All mixtures were proportioned to achieve the 28-day compressive strength of 0.7 MPa (100 psi). The Type A CLSM mixtures consisted of a control mixture (100% fly ash without glass) and five other mixtures with glass, as a replacement of fly ash in the range of 20 to 80 percent. The Type B CLSM mixtures were composed of a control mixture (without glass) and two other mixtures at 30 to 75 percent replacement of sand with glass. The flowable slurry developed in this project satisfied the ACI Committee 229 definition of CLSM. Decreasing the amount of fly ash and increasing the glass content led to increased bleeding and segregation at high replacement levels of 60% and 80%. Permeability of Type A CLSM remained essentially unchanged except at high glass contents it was lower. For Type B CLSM, the permeability was about the same.

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