Utilization of EPS Beats and Polypropylene Fiber in Controlled Low Strength Material

Controlled low-strength material (CLSM) is a self-levelling cementitious material. It is not concrete nor soil-cement, however, it possesses properties similar to both. CLSM is widely used as a replacement for soil-cement material in many geotechnical applications such as structural backfill, pipeline beddings, void fill, pavement bases and bridge approaches. This paper study potential possibility of polypropylene fiber in CLSM. Harden and fresh properties compressive strength , flowability and density for the proposed CLSM were investigated. This CLSM mix design with different percentage of polypropylene fiber and pond ash, cement and water. EPS beats and polypropylene add 0 %, 0.5%, 1.0% and 1.5% of total weight is added in CLSM MIx. Results show that the CLSM incorporating EPS beats and polypropylene satisfies compressive strength requirement as per the requirements of ACI committee 229. polypropylene decreases the flowability of CLSM mix and at the same tine by adding EPS beats the density of CLSM mix are reduce which become lightweight CLSM mix. from this it can conclude that polypropylene fibers is less effective in CLSM mix and EPS beats make CLSM mix lightweight which create lightweight CLSM mix applicable for filling application.

Deltaic Lateritic Soil in 1:5:11 Mix Design for Producing Controlled Low-Strength Material (CLSM) for Pavement Backfill

Deltaic lateritic soil obtained from Emohua in Rivers State, Nigeria was studied to ascertain its suitability as a substitute to sand in concrete for producing controlled low-strength material (CLSM). Cement, coarse aggregate, as well as lateritic soil which replaced sand was combined in ratio 1:5:11 to produce lateritic concrete using varying water-cement (w/c) ratios at varying curing durations. Variation in the w/c ratios ranging from 0.2 to 0.5 at 0.1 intervals and the curing periods which varied between 7, 14 and 28 days were examined. As with the case with conventional concrete, strength development, as well as cement hydration took place after casting over the curing periods. Recent applications using CLSM recommends that a compressive strength of 8.3 N/mm2 or less is required for materials used as conventional compacted backfill soil or structural fillings. In a situation where future excavation is envisioned, it is recommended that the maximum long-term compressive strength of CLSM should generally have an upper limit of 2.1 N/mm2 for compacted backfill material hence, the lateritic concrete produced in this study using the 1:5:11 mix design at 0.2 w/c ratio, cured for 28 days which gave strength of 5.3 N/mm2 can be used as CLSM which primarily, can be utilized as a substitute for compacted backfill to sub-base and/or subgrade of flexible pavements. Where necessary, super plasticizer can be introduced to increase flowability of the lateritic concrete.

Experimental study on the application of red mud to controlled low strength material made of excavated soil

To improve the resource utilization of solid waste, excavation abandoned soil and red mud, a by-product of alumina industry, were introduced into the preparation of controlled low strength material (CLSM). By carrying out the flowability test, bleeding test and compressive strength test, the relationship between properties of CLSM mixture and the amount of red mud was analysed. The experiment results indicate that the flowability and bleeding rate of the mixture decrease with the increase of red mud content. When the red mud content is less than 20%, the mixture shows good flowability. The addition of red mud can accelerate the completion time of bleeding and play a positive role in the bleeding stability of the mixture. When the red mud content is 10%, the strength of the mixture reaches the maximum, while the strength of the mixture with other contents decreases with the increase of red mud content. For the CLSM made of excavated soil, red mud has a good application prospect in terms of bleeding stability and strength.

Effect of Fly Ash on Strength and Stiffness Characteristics of Controlled Low-Strength Material in Shear Wave Monitoring

Fly ash, the main component for controlled low-strength material (CLSM), has physical and chemical characteristics according to the resources used in the thermal power plant, and thus fly ash type can influence the physical and strength properties of CLSM. This study investigates the effect of fly ash type on the engineering properties of CLSM and establishes relationships between mechanical properties of CLSM and shear wave velocity (SWV) for long curing times. Six fly ashes with different physical properties and chemical components are used for preparing the CLSM mixtures. The air content, unit weight, flowability, and setting time of CLSM are measured. Unconfined compressive strength (UCS) and elastic modulus (E) are obtained from unconfined compressive tests, and SWV (Vs) is determined using a bender element-based wave measurement system. Experimental results show that the stiffness and strength characteristics of CLSM are relevant to the contents of two oxides (SiO2 and Al2O3) and the fineness of fly ash. Because the evolution of SWV is influenced by the fly ash type, the relationships UCS-Vs and E-Vs are well established. Thus, considering the fly ash type, shear wave monitoring may be effectively used for estimating strength and stiffness characteristics of CLSM.